An experimental investigation into the pre-treatment of synthetic membranes using sodium hydroxide solutions

In this paper the effect of two pre-treatment methods are compared experimentally for the filtration of (i) a spent sulphite liquor (17.8 wt.% dry solids) using a 20 kg mol⁻¹ molar mass cut off (MMCO) fluoropolymer membrane and (ii) a molasses solution (45° Brix) using a polysulphone (Psf) membrane (1.5 μm pore size). Both feeds are industrially relevant, and subject to severe fouling issues when membranes are used in their subsequent processing. The pre-treatment methods evaluated were: (i) conditioning with water at 60 °C only [Protocol 1], and (ii) conditioning with water at 60 °C followed by cleaning with 0.5 wt.% NaOH [Protocol 2]. Results are presented that confirm the benefits of sodium hydroxide preconditioning upon performance, supporting the suggestion by some membrane manufacturers that this step be included as part of the pre-treatment protocol.     

A tree-structured crash surrogate measure for freeways

In this paper, we propose a novel methodology to define and estimate a surrogate measure. By imposing a hypothetical disturbance to the leading vehicle, the following vehicle’s action is represented as a probabilistic causal model. After that, a tree is built to describe the eight possible conflict types under the model. The surrogate measure, named Aggregated Crash Index (ACI), is thus proposed to measure the crash risk. This index reflects the accommodability of freeway traffic state to a traffic disturbance. We further apply this measure to evaluate the crash risks in a freeway section of Pacific Motorway, Australia. The results show that the proposed indicator outperforms the three traditional crash surrogate measures (i.e., Time to Collision, Proportion of Stopping Distance, and Crash Potential Index) in representing rear-end crash risks. The applications of this measure are also discussed.     

The perils of foreign intervention: the Nile perch disaster for Lake Victoria

The present study involved the use of a pilot scale water treatment plant to treat turbid surface water from a stream using processed Moringa oleifera seed and alum as primary coagulants. At low initial turbidity of 21.5 to 49.3 NTU, residual turbidities of 2.7, 1.8 and 1.4 NTU were achieved after treatment using Moringa oleifera, alum, and alum with Moringa oleifera as coagulant‐aid, respectively. For medium turbidities varying from 51.8 to 114 NTU, lowest residual turbidities of 2.9, 1.2 and 1.4 were achieved after treatment using Moringa oleifera, alum, and alum with Moringa oleifera as coagulant‐aid, respectively. For high turbidity varying from 163 to 494 NTU, minimum residuals of 1.4, 1.9 and 0.9 NTU were achieved after treatment using Moringa oleifera, alum, and alum with Moringa oleifera as coagulant‐aid, respectively. The proposed mechanism for turbidity removal by Moringa oleifera seed in this study is a combination of partial‐charge neutralization and micro‐bridging or an electrostatic patch mechanism based on the results of zeta potential measurements.     

中国煤层气开发利用前景及其未来战略地位

中国煤层气资源十分丰富，埋深小于2000m的煤层气资源量为22.5万亿m^3，我国许多地区煤层气地面勘探开发和井下抽放已经迅速展开，并且取得了突破性的进展，显示了煤层气的良好的开发利用前景。随着我国能源结构的进一步的调整，天然气在一次能源消费中的比重将由目前的不到3％增加到7％，到2020年将有80～220亿m^3供需缺口，届时煤层气产量将达到220亿m^3，形成独立的煤层气产业，成为常规天然气的战略补充资源。     

植物纤维打浆及其对无石棉胶乳抄取板强度的影响研究

研究了植物纤维的打浆性能及其在特种纸无石棉胶乳抄取板中的应用，结果表明：随着磨浆转数的增加，植物纤维的zeta电位逐渐增大，打浆度逐渐增加；在磨浆转数为20000r时，纤维长度和纤维粗度减小明显，细纤维化程度显著，此时的无石棉胶乳抄取板的抗张指数迟到最大值。因此，植物纤维磨浆转数以20000r左右为宜、此时的打浆度为60°SR．     

油田采出水Zeta电位和中值粒径对絮凝效果条件研究

该研究依据动态电泳光散射理论进行Zeta电位测定,利用多个激光源的光束投射测定中值粒径,采用絮凝沉降测定胶体颗粒的絮凝体积及沉降速度.着重考察不同采出水添加剂、聚醚类破乳剂、杀菌剂1227、阻垢剂EDTMP、咪唑啉类缓蚀剂与聚合氯化铝(PAC)复配对颗粒聚集Zeta电位、中值粒径、絮凝体积、沉降速度与颗粒聚集之间的关系...     

圆网浓缩机在文化纸机打浆配料系统中的应用

介绍了圆网浓缩机在文化纸机打浆配料系统中对自制草浆进行二次洗浆中的应用。采用圆网浓缩机洗浆处理后,造纸机湿部系统Zeta电位趋于平衡,有效解决造纸机生产障碍,提高化工辅料使用效率。     

甘蔗渣纤维表面Zeta电位变化特性及其对酶水解效果的影响

将纤维素原料降解为可发酵糖是木质纤维素生物质生物转化乙醇过程中的重要环节,通过对原料的预处理可以提高纤维素酶的催化效率.本文通过改变甘蔗渣纤维的尺寸、添加多聚磷酸盐等方法,发现均能改变蔗渣纤维的表面Zeta电位.初步研究了其Zeta电位变化规律及Zeta电位的变化对纤维素酶水解效果的影响,并对Zeta电位的变化影响纤维...     

Rheological characterization and electrokinetic phenomena of charged whey protein dispersions of defined sizes

A multi-step processing technique produced large colloidal particles from whey proteins, prompting instantaneous thickening upon hydration. Analysis of the rheological characteristics and zeta potential of the modified whey suspensions of defined particle sizes allowed investigation into the role of size on ingredient functionality. Preliminarily, the modified protein powders were sieved to achieve three size ranges, and analyzes were conducted on each of the three distributions and the non-sieved fractions. Following hydration, steady and oscillatory shear analyzes were performed using a controlled stress rheometer to determine rheological characteristics. Intrinsic viscosity was determined with a capillary viscometer and application of the Huggins equation. Zeta potential was calculated from colloidal electrophoretic mobility, measured with a ZetaPALS analyser. After thorough hydration, particle-size analysis revealed a size increase of >1.3 times for each fraction. When analysed on a protein basis, increasing particle size yielded an increase to intrinsic viscosity, flow behavior index, zero shear viscosity, and a decreased zeta potential and consistency coefficient. Knowledge of the interrelationship between zeta potential, rheological properties, and particle size of the modified whey ingredient will further advance an understanding of the functionality of this protein ingredient.     

拒水整理对棉织物洗涤效果的影响研究

为研究拒水整理对棉织物洗涤效果的影响,以不同结构的氟碳拒水拒油整理剂和碳氢类拒水整理剂为研究对象,考察了织物表面能、织物表面Zeta电位、织物的沾污性能等因素对洗涤效果的影响。结果表明,拒水整理后织物表面能的变化与污渍的洗净力大小相关,水溶性污渍的洗净力随着织物表面能的降低而提高;油溶性污渍在未整理的纯棉织物上洗净力最高,而在较低表面能的拒水整理织物上的洗净力最低;随着拒水整理后织物与污渍Zeta电位和绝对值的减小,油溶性污渍的洗净力也有降低的趋势;拒水整理后织物沾污性能的变化也会影响织物的洗涤效果。