30 Years of Progress in Viscometers and Rheometers

1999 ◽  
Vol 9 (2) ◽  
pp. 69-76 ◽  
Author(s):  
Howard A. Barnes ◽  
Harry Schimanski ◽  
Derek Bell

Abstract The history of commercial viscometry and rheometry over the last thirty years is summarised. In terms of those instruments that have established themselves in a lasting position in the field, we highlight the importance of a sound original idea, good marketing, and constant improvement as technology advances. Instruments in this area fall into three categories: simple, low-cost instruments to measure viscosity or at least an equivalent Newtonian viscosity; multi-speed instruments often able to record data on another display or storage device, and rheometers, i.e. instruments capable of a rotational shearing action, as well as one of the following: oscillation, creep and normal force measurement to give some measure of viscoelasticity. The advances in technology in many areas over the past 30 years have all fuelled the rapid development of instruments that has been nothing short of astonishing. Of especial importance has been the continuous developments of electric motors, and transducers, as well as the increases in speed and memory and reductions in price of digital processors and microprocessors. With this increased computing power perhaps with instruments using complex flow regimes it may be as easy to analyse data as with simple shearing now. There will always be, however, those who want to go to higher frequencies, lower deformations, etc., to meet those challenges of measuring the rheology of materials at the limits.

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 515
Author(s):  
Huamin Zhu ◽  
Fuzhong Zheng ◽  
Huiwen Leng ◽  
Cheng Zhang ◽  
Kun Luo ◽  
...  

Microcontact force measurement is widely applied in micro/nano manufacturing, medicine and microelectromechanical systems. Most microcontact force measurements are performed by using mass comparators, nano-indenter and precision electronic balance, and weighing sensors. However, these instruments have a complex structure and high cost. Nevertheless, the rapid development of microsensor technology provides a new, simple and low-cost approach for microcontact force measurement. In this study, we present a method of microcontact force measurement by using micropressure sensors and study the relationship amongst the microcontact force, output voltage and contact position of the sensor. We use a microcapacitance pressure sensor as an example, then we perform a simulation calculation and construct a microcontact force experiment system to verify the simulation results. The experimental and simulation results are consistent. In addition, an equation that describes the relationship amongst the microcontact force, output voltage and contact position of the sensor is obtained. Based on this simple and low-cost method, we build a micro-manipulation system, which indicates that the micropressure sensors can be used to measure microcontact force in various applications easily and cost-effectively. Furthermore, it is considerably relevant to research and application in this field.


2011 ◽  
Vol 239-242 ◽  
pp. 1948-1951
Author(s):  
Lin Qi ◽  
Hong Zhao

The causes that lead to the shrunken cause of dome roof oil tank were analyzed and some practical measures were offered for the prevention of this kind of shrunken, which is valuable about ensuring security of oil tank and protection of external pressure caused destruction in oil tank. With the rapid development of China's oil economy, increased dramatically the demand for large-scale storage and transportation equipment. In the refining and chemical production equipment, the vertical cylindrical steel dome tank is a widely used storage device, it is low cost, easy to operate. Mainly used for storing crude oil, diesel and some chemical products. Tank design pressure is lower, the tank wall, tank top, tank bottom are thinner, and it is easy depression because of large negative pressure inside the tank in the course. Therefore, the correct understanding of the reasons of depression and mastering tank preventive measures, security maintenance for the storage of equipment is very important. In this paper, a refinery in Harbin City, take the dome tank as an example of crude oil and analysis cause of their depression.


2020 ◽  
Vol 10 (7) ◽  
pp. 2296 ◽  
Author(s):  
Chengyu Jin ◽  
Cui Ma ◽  
Zhile Yang ◽  
Hui Lin

With the rapid development of flexible materials, various high-performance biocompatible flexible sensors have been proposed for specific measurement applications. Among these materials, polydimethylsiloxane (PDMS) is one of the most popular polymers by curing the mixture of pre-polymer (base) and cross-linker (curing agent). In this paper, a force measurement method based on PDMS grating is introduced. The PDMS grating is cast from a commercial master grating, which is precise, low-cost, and easy to follow. The elastic modulus can be controlled by the curing temperature and the mixing ratio. The PDMS grating is tested using a tension testing machine. As the stretching force increases, the grating line-spacing simultaneously increases and the diffraction light spot shifts. By capturing the light spot shift using a camera, the relationship between light spot position and stretching force is established and evaluated. Experimental results show that the linearity (R2) of the proposed method is better than 0.998, adding that the sensitivity is ~0.5–0.7N/mm and the accuracy is up to 0.05N.


2019 ◽  
Vol 12 (3) ◽  
pp. 202-211
Author(s):  
Yuancheng Li ◽  
Rong Huang ◽  
Xiangqian Nie

Background: With the rapid development of the Internet, the number of web spam has increased dramatically in recent years, which has wasted search engine storage and computing power on a massive scale. To identify the web spam effectively, the content features, link features, hidden features and quality features of web page are integrated to establish the corresponding web spam identification index system. However, the index system is highly correlation dimension. Methods: An improved method of autoencoder named stacked autoencoder neural network (SAE) is used to realize the reduction of the web spam identification index system. Results: The experiment results show that our method could reduce effectively the index of web spam and significantly improves the recognition rate in the following work. Conclusion: An autoencoder based web spam indexes reduction method is proposed in this paper. The experimental results show that it greatly reduces the temporal and spatial complexity of the future web spam detection model.


Author(s):  
Oriol Bohigas ◽  
Hans A. Weidenmüller

An overview of the history of random matrix theory (RMT) is provided in this chapter. Starting from its inception, the authors sketch the history of RMT until about 1990, focusing their attention on the first four decades of RMT. Later developments are partially covered. In the past 20 years RMT has experienced rapid development and has expanded into a number of areas of physics and mathematics.


1943 ◽  
Vol 3 (S1) ◽  
pp. 1-8
Author(s):  
Curtis P. Nettels

One influence of war has repeatedly asserted itself in the past—an effect on the costs of production and on the competitive position of the industries and firms of victorious or neutral nations. This subject needs more study, but certain facts suggest a hypothesis, of three parts. First: war expands some industries or concerns, increases their efficiency, enables them to operate, at the end of the struggle, on a comparatively low-cost basis, intensifies their competitive advantages, and improves their position in relation to foreign competitors. Second: war—for the duration—bolsters up some high-cost units by enabling them to sell at a profit all they can produce. The end of the war places such high-cost units at a disadvantage in the process of absorbing the shocks of the transition to a peacetime economy. Third: the history of postwar periods usually exhibits a sharp contest between such low-cost and high-cost enterprises. While “low cost” and “high cost” may refer to the relative positions of units within the same country, in most of this discussion, the terms will be applied to the producers of one country (either victor or neutral) to mean that their costs are low or high in comparison with those of their foreign competitors.


2021 ◽  
Vol 11 (15) ◽  
pp. 6831
Author(s):  
Yue Chen ◽  
Jian Lu

With the rapid development of road traffic, real-time vehicle counting is very important in the construction of intelligent transportation systems (ITSs). Compared with traditional technologies, the video-based method for vehicle counting shows great importance and huge advantages in its low cost, high efficiency, and flexibility. However, many methods find difficulty in balancing the accuracy and complexity of the algorithm. For example, compared with traditional and simple methods, deep learning methods may achieve higher precision, but they also greatly increase the complexity of the algorithm. In addition to that, most of the methods only work under one mode of color, which is a waste of available information. Considering the above, a multi-loop vehicle-counting method under gray mode and RGB mode was proposed in this paper. Under gray and RGB modes, the moving vehicle can be detected more completely; with the help of multiple loops, vehicle counting could better deal with different influencing factors, such as driving behavior, traffic environment, shooting angle, etc. The experimental results show that the proposed method is able to count vehicles with more than 98.5% accuracy while dealing with different road scenes.


Author(s):  
Fabian Burmann ◽  
Jerome Noir ◽  
Stefan Beetschen ◽  
Andrew Jackson

AbstractMany common techniques for flow measurement, such as Particle Image Velocimetry (PIV) or Ultrasonic Doppler Velocimetry (UDV), rely on the presence of reflectors in the fluid. These methods fail to operate when e.g centrifugal or gravitational acceleration leads to a rarefaction of scatterers in the fluid, as for instance in rapidly rotating experiments. In this article we present two low-cost implementations for flow measurement based on the transit time (or Time of Flight) of acoustic waves, that do not require the presence of scatterers in the fluid. We compare our two implementations against UDV in a well controlled experiment with a simple oscillating flow and show we can achieve measurements in the sub-centimeter per second velocity range with an accuracy of $\sim 5-10\%$ ∼ 5 − 10 % . We also perform measurements in a rotating experiment with a complex flow structure from which we extract the mean zonal flow, which is in good agreement with theoretical predictions.


Author(s):  
Murat Fidan ◽  
Alper Bayrak ◽  
Umid Karli

In this study, a low-cost and adaptable isometric strength measurement and exercise development system are described. The implemented system consists of mechanical structure, force measurement sensor, electronic circuit, and computer software. Isometric-isotonic (via spring resistance) strength analysis and various exercise programs can be applied with the system. The developed system has a lower cost compared to its counterparts in the literature and has a structure that can be adapted to different machines and measuring methods. The operability and reliability of the isometric strength measurement and exercise development system have been proven by calibration tests.


Author(s):  
Junshu Wang ◽  
Guoming Zhang ◽  
Wei Wang ◽  
Ka Zhang ◽  
Yehua Sheng

AbstractWith the rapid development of hospital informatization and Internet medical service in recent years, most hospitals have launched online hospital appointment registration systems to remove patient queues and improve the efficiency of medical services. However, most of the patients lack professional medical knowledge and have no idea of how to choose department when registering. To instruct the patients to seek medical care and register effectively, we proposed CIDRS, an intelligent self-diagnosis and department recommendation framework based on Chinese medical Bidirectional Encoder Representations from Transformers (BERT) in the cloud computing environment. We also established a Chinese BERT model (CHMBERT) trained on a large-scale Chinese medical text corpus. This model was used to optimize self-diagnosis and department recommendation tasks. To solve the limited computing power of terminals, we deployed the proposed framework in a cloud computing environment based on container and micro-service technologies. Real-world medical datasets from hospitals were used in the experiments, and results showed that the proposed model was superior to the traditional deep learning models and other pre-trained language models in terms of performance.


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