Li M, Brasseur J G, Kern M K, Dodds W J
Department of Mechanical Engineering, Pennsylvania State University, University Park 16802.
Dysphagia. 1992;7(1):17-30. doi: 10.1007/BF02493417.
Detailed viscosity measurements have been made of barium sulfate mixtures over a wide range of viscosities for use in radiography of the esophagus, stomach, and duodenum. A new methodology was developed for more accurate estimation of viscosity in non-Newtonian fluids in conventional cylinder-type viscometers. As base cases, the variation of viscosity with shear rate was measured for standard commercial mixes of e.z.hd (250% w/v) and a diluted mixture of liquid e.z.paque (40% w/v). These suspensions are strongly shear thinning at low shear rates. Above about 3s-1 the viscosity is nearly constant, but relatively low. To increase the viscosity of the barium sulfate mixture, Knott's strawberry syrup was mixed to different proportions with e.z.hd powder. In this way viscosity was systematically increased to values 130,000 times that of water. For these mixtures the variation of viscosity with temperature, and the change in mixture density with powder-syrup ratio are documented. From least-square fits through the data, simple mathematical formulas are derived for approximate calculation of viscosity as a function of mixture ratio and temperature. These empirical formulas should be useful in the design of "test kits" for systematic study for pharyngeal and esophageal motility, and clinical analysis of motility disorders as they relate to bolus consistency.
已对硫酸钡混合物在广泛粘度范围内进行了详细的粘度测量，用于食管、胃和十二指肠的放射造影。开发了一种新方法，用于在传统圆柱型粘度计中更准确地估计非牛顿流体的粘度。作为基础案例，测量了标准商业混合物e.z.hd（250% w/v）和液体e.z.paque稀释混合物（40% w/v）的粘度随剪切速率的变化。这些悬浮液在低剪切速率下具有强烈的剪切变稀特性。在约3s-1以上，粘度几乎恒定，但相对较低。为了提高硫酸钡混合物的粘度，将诺特草莓糖浆与e.z.hd粉末按不同比例混合。通过这种方式，粘度系统地提高到水的粘度的130,000倍。记录了这些混合物的粘度随温度的变化以及混合物密度随粉末-糖浆比例的变化。通过对数据进行最小二乘法拟合，得出了用于近似计算粘度作为混合物比例和温度函数的简单数学公式。这些经验公式在设计用于系统研究咽部和食管运动以及与食团稠度相关的运动障碍临床分析的“测试试剂盒”时应会很有用。
