Modeling Viscosity of Multicomponent Electrolyte Solutions

A comprehensive model for calculating the viscosity of aqueous electrolyte solutions has been developed. The model includes a long-range electrostatic interaction term, contributions of individual ions, and a contribution of specific interactions between ions or neutral species. The long-range electrostatic term is obtained from the Onsager–Fuoss theory, whereas the individual ionic contributions are calculated using the Jones–Dole B coefficients. A technique for predicting the temperature dependence of the B coefficients has been developed on the basis of the concept of structure-breaking and structure-making ions. The contribution of specific interactions between species, which is dominant for concentrated solutions, has been found to be a function of the ionic strength. The model reproduces the viscosity of aqueous systems ranging from dilute to concentrated solutions (up to ca. 30m) at temperatures up to 573 K with an accuracy that is appropriate for modeling industrially important systems. In particular, the viscosity of multicomponent systems can be accurately predicted using parameters obtained from single-solute systems.     

壳聚糖的酯化反应研究

讨论了壳聚糖乙酯／甲酯的制备以及反应温度、反应时间、反应试剂用量对酯化反应的影响。测定了产物的粘度、取代度、溶解性能。实验结果表明，反应产物的溶解性能随取代度的增加而提高。     

粘度测量的几种方法

文章介绍了粘度测量的过程毛细管技术以及几种直接或间接测量粘度的新方法。     

阳离子型有机高分子絮凝剂性能表征及应用

针对阳离子型有机高分子絮凝剂的应用性能，采用胶体滴定和黏度测定简单实用的方法进行表征。介绍了该絮凝剂的阳离子电荷密度和相对黏度指标对高色度废水脱色效果的影响和规律，并介绍了絮凝剂在工业化装置上的应用。     

河流相储层油藏无因次采液指数计算的典型通用公式

目的准确认识油田动态变化规律，为油田的开发设计，开发调整及开发分析提供重要依据。方法：根据建立的河流相储层渗透率一面非均质抽象模型以及河流相储层的典型参数，考虑油水粘度比、油水井数比、井距不均匀系数、井网密度、平面渗透率对数正态分布变异系数、     

RHEOLOGICAL AND PHYSICOCHEMICAL BEHAVIOR OF FORTIFIED YOGURT, WITH FIBER AND CALCIUM

Yogurt systems were prepared from whole milk, adding 50 mg of calcium/100 mL of yogurt, and three levels of fiber from two wheat‐bran sources. In comparison with a plain yogurt, the presence of fiber and calcium augmented the consistency, diminished the syneresis and the pH was higher. Fiber increased the consistency, and all the formulated samples exhibited a non‐Newtonian response. During 3 weeks of storage time, the consistency reduced (from 2.0 to 0.32 Pa·s ⁿ ), syneresis increased (from 20 to 48%) and pH decreased (from 4.5 to 4.2) as a function of the system formulation.     

Laminar nanofluid flow in microheat-sinks

In response to the ever increasing demand for smaller and lighter high-performance cooling devices, steady laminar liquid nanofluid flow in microchannels is simulated and analyzed. Considering two types of nanofluids, i.e., copper-oxide nanospheres at low volume concentrations in water or ethylene glycol, the conjugated heat transfer problem for microheat-sinks has been numerically solved. Employing new models for the effective thermal conductivity and dynamic viscosity of nanofluids, the impact of nanoparticle concentrations in these two mixture flows on the microchannel pressure gradients, temperature profiles and Nusselt numbers are computed, in light of aspect ratio, viscous dissipation, and enhanced temperature effects. Based on these results, the following can be recommended for microheat-sink performance improvements: Use of large high-Prandtl number carrier fluids, nanoparticles at high volume concentrations of about 4% with elevated thermal conductivities and dielectric constants very close to that of the carrier fluid, microchannels with high aspect ratios, and treated channel walls to avoid nanoparticle accumulation.     

木质素磺酸盐/有机硅氟共聚物复合降黏剂研究

为了适应环保和复杂地质钻探要求,采用木质素磺酸盐、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酸(AA)和二甲基二烯丙基氯化铵(DMDAAC)接枝共聚,合成AMPS/AA/DMDAAC-木质素磺酸盐接枝共聚物,再将该接枝共聚物与有机硅氟共聚物复配成无毒、无污染、高效的钻井液复合降黏剂,对其在钻井液中的降黏性能进行了室内评价。结果表明,复合降黏剂可使淡水钻井液的表观黏度和动切力明显降低,可获得较好的降黏效果;复合降黏剂在盐水钻井液、聚合物钻井液和含钙钻井液中也具有较好的降黏作用;复合降黏剂在不同钻井液中老化后钻井液的表观黏度、动切力均未有明显的增加。研究结果表明,该复合降黏剂是一种热稳定性好、降黏和抗温抗盐能力强的降黏剂。     

Viscosity correlation for aqueous polyvinylpyrrolidone (PVP) solutions

Polyvinylpyrrolidone (PVP) is characterized by its K‐value, which is a function of the average molecular weight, the degree of polymerization, and the intrinsic viscosity. The viscosity was measured for aqueous PVP solutions with K‐values ranging from 92.1 to 95.4 and with concentrations from 2 to 3 weight percent. A correlation was determined that relates solution viscosity to the K value and weight percent PVP, which is particularly useful in its use as a photoresist in the manufacture of high resolution display screens. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1153–1155, 2003