一种聚四氟乙烯毛细管Ubbelodhe粘度计

改进型乌式粘度计;高分子溶液;一种聚四氟乙烯毛细管Ubbelodhe粘度计;聚电解质粘度效应     

以六氟异丙醇为溶剂的聚甲醛凝胶渗透色谱研究

研究了均聚和共聚甲醛在六氟异内醇中的凝胶渗透色谱（ＧＰＣ）。对共聚甲醛出现的缔合现象从主链结构作了解释，并找到了避免缔合的方法；对共聚甲醛ＧＰＣ淋洗曲线上的异常小峰从聚合机理角度进行了探讨，推测得到小峰所对应的物质。确定了以六氟异丙醇为溶剂的聚甲醛的凝胶色谱表征方法，并探索采用凝胶色谱－粘度计联用法得到分子量和分子量分布结果。     

垂直落球粘度计

介绍垂直落球粘度计的结构原理,进行了不确定度分析,并利用国家一级标准物质进行了验证。     

Experimental Study of the Effect of Temperature,Pressure and Concentration on the Viscosity of Aqueous NaBr Solutions

The viscosity of 10 (0.049, 0.205, 0.464, 0.564, 0.820, 1.105, 1.496, 2.007, 2.382, and 2.961 mol ċ kg⁻¹) binary aqueous NaBr solutions has been measured with a capillary-flow technique. Measurements were made at pressures up to 40 MPa. The range of temperature was 288–595 K. The total uncertainty of viscosity, pressure, temperature and composition measurements were estimated to be less than 1.6%, 0.05%, 15 mK, and 0.02%, respectively. The effect of temperature, pressure, and concentration on viscosity of binary aqueous NaBr solutions were studied. The measured values of the viscosity of NaBr(aq) were compared with data, predictions and correlations reported in the literature. The temperature and pressure coefficients of viscosity of NaBr(aq) were studied as a function of concentration and temperature. The viscosity data have been interpreted in terms of the extended Jones–Dole equation for the relative viscosity (η/η₀) to calculate accurately the values of viscosity A- and B-coefficients as a function of temperature. The derived values of the viscosity A- and B-coefficients were compared with the results predicted by the Falkenhagen–Dole theory of electrolyte solutions and calculated with the ionic B-coefficient data. The physical meaning parameters V and E in the absolute rate theory of the viscosity and hydrodynamic molar volume V k were calculated using the present experimental viscosity data. The TTG model has been used to compare predicted values of the viscosity of NaBr(aq) solutions with experimental values at high pressures.     

R143a气相黏度的实验研究

采用振动盘黏度计对制冷剂R143a的气相黏度进行了实验研究,温度范围为299～338 K、压力范围为0.1～2.69MPa,黏度测量的不确定度为±2.0%.利用得到的实验数据,拟合了R143a的气相黏度方程,黏度实验数据与方程的平均绝对偏差为0.20%,最大偏差为0.97%,可以满足工程应用.     

Zur Darstellung der Verkleisterungseigenschaften der Stärke in Rotationsviskosimetern

Zusammenfassung Das Verkleisterungsverhalten einer Stärke oder eines stärkehaltigen Materials (Mehl) wird üblicherweise mittels einer kontinuierlichen Viskositätsmessung bei definiert steigenden Temperaturen in einem Rotationsviskosimeter mit Relativ-Meßkörpern erfaßt. Die Strömungsverhältnisse in einer solchen Meßeinrichtung werden phänomenologisch beschrieben, der Einfluß der Konzentration der Mehlsuspensionen und der Teige (15–60% Trockensubstanz) und der Temperatursteigerungsgeschwindigkeit (0,5–3,0 °C/min) auf das Meßergebnis wird untersucht. Beide Meßparameter bewirken deutliche Veränderungen sowohl in der Viskosität der Suspension bzw. der Teige, als auch in der Temperatur als Zeitfunktion, bei der die Viskositätsveränderungen stattfinden. Dieses Verhalten wird mit dem zeitabhängigen Wasserbindevermögen, der Quellung und der Verkleisterung der Korninhaltsstoffe gedeutet, und es wird auf die Notwendigkeit hingewiesen, diese Tatsache bei der Auswertung und dem Vergleich der Verkleisterungskurven zu berücksichtigen.

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The glutinization behaviour of starch or starch-rich materials (such as flour) is usually determined by means of the continuous measurement of viscosity at a defined rate of temperature increase in a rotational viscometer providing relative measurements. The flow behaviour in such a measuring device is described phenomenologically and the influence of the concentration of the flour slurries or doughs (15–60% dry substance) and the rate of temperature increase (0.5 to 3.0 °C/min) on the results is investigated. Both parameters cause distinct changes in the viscosity of the slurries or doughs as well as in the time-dependent behaviour of the temperature at which the changes in viscosity occur. This behaviour is explained in terms of the swelling, the glutinization and the time-dependent water absorption capacity of the flour. It is pointed out that these facts must be considered when evaluating and comparing glutinization curves.

Veröffentlichung Nr. 5077 der Bundesforschungsanstalt für Getreide- und Kartoffelverarbeitung in Detmold, vorgetragen auf der Jahrestagung der Deutschen Rheologischen Gesellschaft in Ulm vom 7.–10. März 1983.     

A new instrument for measuring the viscoelastic properties of dilute polymer solutions

A new oscillating capillary viscometer has been developed and used for measuring viscoelastic flow properties of dilute polymer solutions. These flow properties are determined from measurements of the pressure to volume flow relationships for sinusoidal flow in cylindrical glass capillaries. The theory for this measurement procedure is based upon the known theory for oscillatory flow of a viscoelastic fluid in circular tubes and which is presented with a few supplementations in this paper.The oscillatory flow is generated by a piezoelectric driver which is dipped directly into the aqueous solution. The advantage of this driver is that the excitation voltage for the piston is a direct measure of the motion of the piston. Changes in pressure are measured with a sensitive low-pressure quartz tranducer.The viscometer was tested with aqueous glycerol solutions and a gelatin gel. The viscoelastic flow properties of dilute polymer solutions (gelatin, gelatin/color-coupler, polyacrylamide) were then investigated in the frequency range 5 Hz to 150 Hz at very small volume flow amplitudes. The results presented illustrate the suitability of the method. The results are also evaluated with regard to the stabilizing action of slightly viscoelastic gelatinous coating liquids in the high-speed coating process in the manufacture of photographic materials.     

Experimental Study of the Effect of Temperature,Pressure, and Concentration on the Viscosity of Aqueous KBr Solutions

The viscosity of five (0.1240, 0.2378, 0.4645, 0.9440, and 2.2310 mol⋅kg⁻¹) binary aqueous KBr solutions have been measured with a capillary flow technique. Measurements were made at pressures up to 30 MPa for the temperature range 298 to 577 K. The total uncertainties of the viscosity, pressure, temperature, and composition measurements were estimated to be less than 1.6%, 0.05%, 15 mK, and 0.02%, respectively. The temperature and pressure coefficients of the viscosity of KBr(aq) were studied as a function of molality and temperature. The measured viscosities were compared with data, predictions and correlations previously reported in the literature. The viscosity data were used to accurately calculate the physical-meaningful parameters (viscosity A- and B-coefficients) of the extended Jones-Dole equation for the relative viscosity (η/η ₀). Various theoretical models {absolute rate theory, Tammann-Tait-Gibson (TTG) model, and extended Einstein model} were used to accurately represent the measured viscosities. Values of hydrodynamic molar volume V _k (effective rigid molar volume of the salt) were calculated using the present experimental data. The high-pressure viscosity measurements were used to test the predictive capability of the TTG model.     

Ion Migration and Frequency-Dependent Dielectric Loss

Abstract

The frequency-dependent dielectric loss due to ion migration in a solvent with a given dielectric function ?(ω) is calculated explicitIy within the following framework:

i) The solvent is treated in the dielectric continuum model

ii) The Navier-Stokes equation is solved for the velocity field

iii) The limiting cases of (a) large ion radius (weak coupling) and (b) point ions (strong coupling) are treated explicitly.

The most clearcut prediction of the theory is that the incremental frequency-dependent conductivity is proportional to ω^¼ at high frequencies, the power law being independent of the form of ?(ω). For arbitrary frequencies, in the limits (a) and (b) above, the incremental frequency-dependent conductivity can be calculated explicitly given the dielectric function of the solvent.