Effect of medium viscosity on rheological characteristics of magnetite-based magnetorheological fluids

2019 ◽  
Vol 80 ◽  
pp. 197-204 ◽  
Author(s):  
Ehsan Esmaeilnezhad ◽  
Seyed Hasan Hajiabadi ◽  
Hyoung Jin Choi
Keyword(s):  
Magnetorheological Fluids ◽  
Rheological Characteristics ◽  
Medium Viscosity

ANALYSIS OF THE POTENTIAL USAGE OF SELECTED MAGNETIC FLUIDS IN THRUST SLIDE BEARINGS

Tribologia ◽  
2016 ◽  
Vol 269 (5) ◽  
pp. 41-49 ◽  
Author(s):  
Wojciech HORAK ◽  
Józef SALWIŃSKI ◽  
Marcin SZCZĘCH
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Mechanical Energy ◽  
Magnetic Fluids ◽  
Magnetorheological Fluids ◽  
Machine Design ◽  
Rheological Characteristics ◽  
New Horizons ◽  
Controlled Systems ◽  
Ferromagnetic Fluids

Magnetic fluids are substances whose rheological properties can be actively influenced by treatment with a magnetic field. Two main types of magnetic fluids can be distinguished: ferromagnetic fluids, and magnetorheological fluids. Ferrofluids are mostly used in sealing engineering, whereas magnetorheological fluids are usually applied in controlled systems for the dissipation of mechanical energy, like brakes and dampers. The ability to control the rheological properties of magnetic fluids opens new horizons for development in machine design, among others in the areas of bearing engineering. The paper presents a comparative analysis of the rheological characteristics of selected magnetic fluids with a focus on the possible areas of the application of these substances in bearing engineering.

Synthesis and rheological characteristics of high viscosity linear polysiloxane carrier fluid-based magnetorheological fluids

2021 ◽  
Author(s):  
Lei Xie ◽  
Young-Tai Choi ◽  
Changrong Liao ◽  
Zhi Zeng ◽  
Norman M Wereley
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Particle Concentration ◽  
High Viscosity ◽  
Magnetorheological Fluids ◽  
Test Method ◽  
Fluid Viscosity ◽  
Rheological Characteristics ◽  
Carrier Fluid ◽  
Field Dependent

Abstract This study addresses the synthesis and field-dependent rheological characteristics of novel magnetorheological fluids (MRFs) using high viscosity linear polysiloxanes (HVLPs) as a carrier fluid. First of all, the components and preparation of novel HVLP-based MRFs (HVLP MRFs) were explained in detail and the microscopic images of each component were taken by using scanning electron microscope (SEM). Four HVLP MRF samples with different particle volume fractions of 10, 15, 20, and 26 vol% in the same HVLP carrier fluid viscosity of 800 Pa·s were synthesized to investigate the particle concentration effect on their field-dependent rheological properties. In order to understand the effect of the carrier fluid viscosity, two more HVLP MRF samples with different HVLP viscosities of 140 and 440 Pa·s in the same particle concentration of 26 vol% were also fabricated. In addition, the temperature effect on HVLP MRFs was studied by using the sample with 26 vol% in particle concentration and 140 Pa·s in HVLP viscosity under different operating temperatures of 25, 40, 55 and 70℃. The flow curve measurements of shear stress versus shear rate in the magnetic fields were conducted by using controlled shear rate (CSR) test method with a commercial parallel-plate type rotational rheometer. From the flow curves, the field-dependent rheological properties of HVLP MRFs including static and dynamic yield stresses and the dynamic range (ratio of field on to field off yield stress) were obtained. These material characteristics were then examined as a function of varying particle concentration, varying carrier fluid viscosity, and varying temperature. A conventional commercial MRF (i.e., Lord MRF-126CD) was adopted for comparison study and its rheological properties under different temperatures were also measured and compared with those of HVLP MRFs. Using HVLP carrier fluids, it was demonstrated that the HVLP MRFs exhibited much greater suspension stability than the conventional commercial MRF.

Some Recent Developments in Sewage Sludge Pumping

1988 ◽  
Vol 20 (4-5) ◽  
pp. 227-236
Author(s):  
J. H. Lohmann ◽  
W. F. Garber
Keyword(s):  
Sewage Sludge ◽  
Treatment Plant ◽  
Rheological Characteristics ◽  
Volatile Content ◽  
Collection System ◽  
Positive Displacement ◽  
Low Viscosity ◽  
Recent Developments ◽  
Cylinder Piston ◽  
Pumping Equipment

The pumping of sewage sludge solids is reviewed in terms of handling high and low viscosity materials with solids concentrations varying from about 4 % to perhaps 50 %. Knowledge of rheological characteristics including thixotropy is necessary in designing pumping systems with sludge solids percentages, volatile content, particle size, abrasives content and temperatures being variables which could change pump types found suitable from facility to facility. The characteristics of a sewage collection system is also important in determining pumping parameters needed in a treatment plant. Solids handling equipment from other industries have made significant contributions to sewage solids pumping in recent years. Included are moyno-type progressing cavity screw-centrifugal, recessed impeller rotation piston positive displacement, and two cylinder piston S-transfer positive displacement pumps. Pumping equipment used in the F.R.G. and in Southern California in the U.S.A. is remarkably similar. These types of pumps offer the possibility of designing optimum solids dewatering and transfer systems.

Rheological Characteristics and Methodology of Ice Cream: A Review

2020 ◽  
Vol 16 (5) ◽  
pp. 666-674
Author(s):  
Amir M. Mortazavian ◽  
Najme Kheynoor ◽  
Zahra Pilevar ◽  
Zhaleh Sheidaei ◽  
Samira Beikzadeh ◽  
...  
Keyword(s):  
Process Design ◽  
Flow Behavior ◽  
Ice Cream ◽  
Rheological Parameters ◽  
Rheological Characteristics ◽  
Rheological Analysis ◽  
Fundamental Information ◽  
Food Structure ◽  
Analytical Tools ◽  
Penetration Tests

The rheological analysis is important analytical tools used to obtain fundamental information about food structure. For instance, the properties of flow of liquid and semi-solidity are characterized by the consistency and flow behavior experiments as two important rheological parameters. The rheological parameters of foods are applied in quality control of the products and processing of food products such as energy input calculations, process design, equipment selection, and especially for deciding on heat exchangers and pumps. Steady flow behavior, oscillatory, and penetration tests are among commonly used parameters for evaluating rheological characteristics of ice cream. The purpose of this paper is to provide an overview of recent experiments and methods for measuring the rheological and texture properties of ice cream.

Investigating the Rheological Properties and Heat Stability of Polyarylsulphone Sulphides of Domestic Grades

2017 ◽  
Vol 44 (1) ◽  
pp. 23-26
Author(s):  
A.B. Baranov ◽  
I.D. Simonov-Emel'yanov ◽  
T.I. Andreeva ◽  
T.N. Prudskova ◽  
V.I. Sazikov
Keyword(s):  
Molecular Weight ◽  
Heat Stability ◽  
Chain Structure ◽  
Low Flow ◽  
Processing Temperature ◽  
Rheological Characteristics ◽  
Melt Viscosity ◽  
Full Curve ◽  
Temperature Range ◽  
Service Characteristics

The rheological characteristics of melts of polyarylsulphone sulphides of domestic grades were investigated in the temperature range 240–360°C. Full curves of heat stability were obtained, and formulae were proposed for their description. Polyarylsulphone sulphides (PSPSs) are heat-resistant polymers of structural designation of the polysulphone (PSP) class, the domestic production technology of which was developed at OAO “Institut plastmass”, which makes it possible to carry out the production of a wide grade range of PSP of different polymer chain structure and molecular weight. The main problem in the processing of PSPSs is their high melt viscosity and fairly low flow. Increase in the processing temperature lowers their melt viscosity, but there is then the danger of thermooxidative degradation of the polymer and consequently of deterioration in the service characteristics and appearance of articles. The aim of this work was to investigate the rheological characteristics and to obtain the full curve of heat stability for domestic grades of PSPSs and PSP of different molecular weight in a wide processing temperature range.

Antibiotic Distribution in a Bone Cement Spacer Model

2007 ◽  
Vol 17 (4) ◽  
pp. 218-223 ◽  
Author(s):  
K. Shiramizu ◽  
V. Lovric ◽  
A.M.D. Leung ◽  
W.R. Walsh
Keyword(s):  
Liquid Phase ◽  
Bone Cement ◽  
Cross Sections ◽  
High Dose ◽  
Cement Spacer ◽  
Traditional Technique ◽  
Low Viscosity ◽  
Significant Difference ◽  
Group A ◽  
Medium Viscosity

Purpose To mix high dose antibiotic powder to the bone cement more easily, Hanssen et al reported mixing the antibiotics with the cement during its liquid phase but made no comments about the relevance of cement viscosity and antibiotic distribution. The purpose of this study was to investigate the effect of the cement mixing technique and cement viscosity on the antibiotics distribution in a cement spacer model. Methods Thirty cylindrical models from three groups were examined. Group A was made by mixing the antibiotics with medium viscosity cement prior to adding the liquid monomer (traditional technique). Group B was made by mixing the antibiotics with medium viscosity cement during its liquid phase (Hanssen's technique). Group C was made by traditional technique with low viscosity cement. In all groups 2 g of tetracycline was used. Three 0.1 mm thick cross sections from each spacer model were examined under the fluorescent microscope. The fluorescent spots of tetracycline were calculated automatically in pixels. To evaluate the distribution of the antibiotics in the spacer model, we selected the cross section with the highest number of pixels and the one with the lowest number of pixels from each of the three cross sections and calculated the difference between them. The distribution disequilibrium was compared between group A and B, A and C. Results No significant difference was observed in either comparison. Conclusion The Hanssen's mixing technique can be used when using high dose antibiotics, and either medium or low viscosity cement could be used in terms of antibiotic distribution.

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