如何正确使用标准物质对DNJ—1型旋转粘度计进行检定

本文探讨了对DNJ-1型旋转粘度计进行检定过程中，正确使用标准物质应注意的问题。     

JJG 1002-2005《旋转黏度计检定规程》不适合血液黏度计检定的原因分析

血液是一种非牛顿体，血液粘度作为预防和判断高血压、中风、心肌梗塞等病的一个重要参数已经越来越受到医药、生化、环境科学等领域的关注。目前，测定血液粘度的仪器选择、实施测定方法、评判标准等方面大多留于学术界的讨论。当今临床检测中，血液流学仪器的种类繁多，但方法原理不一，参数设置，软件特点不同等情况，造成测定结果的可比性较差，所以对该类仪器检测的技术规范和评判标准的统一是相当重要和紧迫的。 最近颁布的JJG1002-2005《旋转黏度计检定规程》涵盖了各种旋转粘度计的检定要求，其中虽然提及了测定非牛顿体的血液粘度计的相关内容，但从测量范围、标样选取、环境要求、结果评判等方面还存在着一些有争议的问题。 《JJG1002-2005〈旋转黏度计检定规程〉不适合血液粘度计检定的原因分析》一文及时地提出了这些问题，文中的许多技术内容是由作者在长期的实践中总结而来，比较客观，更重要的是作者由此提出了一个以往很少提及但又非常必要的问题，即应该尽快专项制定关于血液粘度计的检定规程或校准规范以确保该参数在其应用领域里量值的准确和统一。 本刊刊登下文，旨在引发业内人士更多的讨论，在介绍检测方法，分析数据或实例，在提出问题同时表明技术上的解决方案等方面提供更多更好的经验。[编者按]     

流出杯式粘度计校正系数不确定度评定分析

本文根据JJG743-91流出杯式粘度计检定规程,对影响流出杯式粘度计校正系数的因素进行逐一分析。并以实验数据为基础对该校正系数进行测量不确定度评定,给出不确定度结果。     

旋转粘度计使用中必须注意的几个问题

旋转粘度计广泛应用于测定油脂、油漆、涂料、塑料、食品、药物、胶粘剂等各种流体的动力粘度。该仪器结构简单、价格便宜、方便实用,因而广受欢迎。在长期从事该类仪器的检定过程中我们发现许多用户,特别是中小企业的测试人员在使用过程中存在许多问题,往往我们检定的仪器性能优于国家计量检定规程的要求,但是用户在测试样品时数据偏差很大。现就如何正确使用该类仪器获得准确可靠的测量结果分析如下。     

流出杯式粘度计校正系数的测量不确定度评定

文章介绍了流出杯式粘度计校正系数的不确定度评定并给出结果.     

如何正确使用标准物质对NDJ-1型旋转粘度计进行检定

本文探讨了对NDJ -1型旋转粘度计进行检定过程中 ,正确使用标准物质应注意的问题     

可用于多种测量对象的在线粘度计／密度计

可用于多种测量对象的在线粘度计／密度计盐田健１．前言粘度计／密度计过去大多是在实验室中使用，近年来随着各种工厂的自动化，与用于工程管理和产品管理的压力计和流量计一样，有必要开发出作为工业测量器具能够在线使用的粘度计／密度计。对粘度计／密度计以及在线使...     

T-bar转子在刻度盘式旋转粘度计上应用的研究

刻度盘式旋转粘度计作为经典的标准粘度计配有相应的常规转子,T-bar转子作为非常规转子未在刻度盘式旋转粘度计上得到应用。现对此类非常规转子在刻度盘式旋转粘度计上应用的可行性进行理论分析。经过优化设计将T-bar转子应用在了刻度盘式旋转粘度计上,给出了一种T-bar转子校准的有效方法。将T-A、TB、T-C转子校准为04、05、06号转子,其扩展不确定度均为1%。实现了T-bar转子在刻度盘式旋转粘度计上的应用。     

NDJ-1型旋转黏度计常见故障及处理办法

旋转黏度计广泛应用于测定油脂、油漆、塑料、食品、药物、黏胶剂、化妆品膏霜类等各种流体的黏度。现以常见的NDJ—1型旋转黏度计(共轴圆筒旋转黏度计)为例，向大家介绍其常见故障的维修。     

高温双毛细管粘度计恒温系统研究

准确测定热力学温度是制定国际温标的基础,在温度计量研究中具有重要的科学意义.声学共鸣法是当前最有影响的基准热力学测温方法之一,该方法最大测量不确定度来源于实际气体粘性作用所造成的能量耗散效应,故准确地测定实际气体粘度,对声学共鸣法热力学温度计的应用具有关键影响.在120℃以下的实验研究证实,双毛细管粘度计具有最小的气体粘度测量不确定度.在此基础上,设计建立了一套高温双毛细管粘度计,优化了恒温装置结构设计,研究了该恒温器控温方法,使得恒温系统在室温至400℃,5h的温度稳定性达到±3mK,满足双毛细管粘度计测量高温气体粘度实验要求.     

Surface-tension effects in suspended-level capillary viscometers

The results of an experimental study of surface-tension effects in kinematic capillary viscometers of the suspended-level type are presented. These results are deduced from a comparison with measurements obtained with a special Ostwald viscometer in which surface-tension effects are negligibly small. It is shown that surface-tension effects in suspended-level viscometers are sensitive to the shape of the capillary exit. Recommendations how to minimize these effects are discussed.     

Magnetic rotating disk viscometer

A rotating disk viscometer has been developed aiming at measuring the viscosity at the critical consolute point of binary mixtures in the true hydrodynamic limit. The viscometer consists of a small magnetized disk set into slow rotation by a uniformly rotating magnetic field. The liquid is continuously sheared and no frequency effects should manifest even at the critical point. The phase delay between field and disk depends on the torques acting on the disk, including that of viscous nature. The viscosity can be calculated from the knowledge of the viscous torque obtained after calibration of the viscometer using literature data for ethanol. Preliminary testing results obtained with this novel apparatus are reported.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

采用拟牛顿流体原理确定冶金熔体流动特性的方法

根据冶金熔体的物理化学性质，可以确定冶金熔体是属于性流体，利用同一牛顿流体在任何剪切速率下的粘度桢的这一特点，给出了一个用拟牛顿流体原理检验冶金熔体的流动特性的方法。钭普通固定转速高温粘度计改造为可调转速，可同熔体的流动特性，进而能确定熔体是否为牛顿流体。     

Transversely Oscillating MEMS Viscometer: The “Spider”

The analysis of a new viscometer that takes the form of an oscillating plate, fabricated from silicon using the methods of micro-electro-mechanical-systems (MEMS) is considered. The instrument is designed principally for experimental use in the oil industry. The plate is 1.6 mm wide, 2.4 mm long, and 20μm thick. It is suspended from a 0.4 mm thick support by 48 square cross-section legs, each of length 0.5 mm width and depth of 20μm. The process of lithography is used to deposit layers atop the silicon. These layers can then be formed into resistors and metallic tracks. The tracks traverse the supporting legs to provide connections between the plate and external electronics. The oscillating plate is a mechanical element that can be set in motion by the force produced by the interaction between an electric current flowing in the plate and an externally applied magnetic field. The viscometer can be operated either in forced or transient mode and is intended for use in both Newtonian and non-Newtonian fluids. The motion of the viscometer is analyzed for incompressible fluids, using the Navier–Stokes equations to model the flow for both a Newtonian viscous fluid and a viscoelastic fluid where the stress is modeled by a reduced form of Maxwell’s equations.Paper presented at the Seventeenth European Conference on Thermophysical Properties, September 5–8, 2005, Bratislava, Slovak Republic.     

一种适用于低沸点混合制冷剂粘度测量装置的研制

针对混合制冷剂等挥发性混合物粘度测量的需要,研制了一种新的适用于测量低沸点混合物粘度的旋转式毛细管粘度计。该新型粘度测量装置在压力容器内嵌入旋转式毛细管粘度计,将旋转法升液和压力容器承压结合起来,避免了传统密封型毛细管粘度计由于抽放气的升液方式而导致混合物成分的变化,可以实现在较高压力下循环测量挥发性混合物溶液的粘度。采用R22和R290对旋转式毛细管粘度计进行了标定,并用R410A对粘度计的测量精度和性能进行了评价,粘度测量值与文献值最大相对偏差为0.81%。     

A High-Temperature Viscometer for Molten Materials

An oscillating-cup viscometer for the measurement of the viscosity of molten materials from room temperature to 1400 K was developed. The instrument is described in detail and the working equations are presented. The operational behavior was tested with water at room temperature. Preliminary measurements show that the new viscometer is capable of measuring the viscosity of water at room temperature to within 0.2%. As the primary objective of this work is the establishment of standard reference data for high-temperature viscosity measurements in molten salts, molten metals, and molten semiconductors, references of earlier viscosity measurements of molten KNO₃ are given.     

Application of in-line viscometer for in-process monitoring of microcrystalline cellulose-carboxymethylcellulose hydrogel formation during batch manufacturing

Physical stability and consistent dose delivery of pharmaceutical suspension formulations comprised of microcrystalline cellulose (MCC) and sodium carboxymethylcellulose (NaCMC) hydrogels is dependent on their rheological properties. To obtain the desired rheological characteristics, good control of the hydrogel dispersion in water is required. The goal of this study was to evaluate whether the XL7-100 Process Viscometer could be employed as a process analytical technology (PAT) tool to monitor the dispersion process in real time during batch manufacturing. Using this instrument, viscosity profiles were measured during the hydrogel processing for a range of operating conditions. It was confirmed that viscosity obtained by the XL7-100 Process Viscometer in the off-line mode, could be linearly correlated to that of the conventional Brookfield viscometer. In addition, the XL7-100 Process Viscometer was able to detect variations in the hydrogel concentrations as well as process conditions in real time. Under fixed operating conditions, the dynamic viscosity profile showed low variability and good inter-batch reproducibility for a properly dispersed hydrogel. For a well-validated mixing process, an off-trend in-line viscosity reading may be indicative of batch failure or poor dispersion homogeneity. Therefore, the in-line viscometer can be used in manufacturing to monitor the batch to batch consistency. However, it is not proven to be able to characterize the real-time structure formation of the hydrogel. It is recommended that the in-line viscometer be used as a complimentary tool along with the off-line rheometer for both efficient and effective in-process quality control of the MCC & NaCMC hydrogel dispersion.     

A New High-Temperature Oscillating Cup Viscometer

A new oscillating cup viscometer for temperatures up to 2,300°C has been constructed. A vacuum furnace with a graphite heater is used for heating the sample. The temperatures of the furnace and sample are measured by both a thermocouple and a pyrometer. The temperature is controlled with a stability better than 1 K. The oscillation of the cup is measured with a reflected laser beam using a position sensitive detector. The measured values of angle and time are then fitted to an analytical oscillation function. From the parameters of this function, the viscosity values are calculated using the Roscoe formalism. Measurements were carried out on pure metals at temperatures up to 1,700°C because of limitations of the thermocouple. The obtained viscosity values showed good agreement with literature data.     

The viscosity of liquid water at pressures up to 32 MPa

The paper reports new, preliminary measurements of the viscosity of liquid water along two isotherms as a function of pressure up to 32 MPa. The measurements have been performed with a vibrating-wire viscometer especially modified for the purpose. The instrument has been calibrated with respect to the viscosity of water at a pressure of 0.1 MPa and a temperature of 293.15 K, for which an accurate reference value is available. With due regard to the precision of the determination of individual quantities and the accuracy of the calibration data, it is estimated that the accuracy of the present results is one of ±0.3% under all conditions.Paper dedicated to Professor Joseph Kestin.     

Rheological models for cement pastes

Shear stress and shear rate data obtained for cement pastes were correlated by means of different rheological models. Pastes were prepared from a commercial Portland cement 325 at different water/cement ratios ranging from 0.34 to 0.42. Tests were performed at 25°C using a rotating coaxial cylinder viscometer. The investigation was accomplished by means of a hysteresis-cycles procedure. On the basis of the goodness of fit, the Herschel-Bulkley model seemed to be very effective for application to cement pastes.