Data on Fluid and Solid Rheology Detailed by Researchers at Polytechnic University (Yield stress and flow behavior of concentrated ferrofluid-based magnetorheological fluids: the influence of composition)
By a News Reporter-Staff News Editor at Journal of Technology -- Current study results on Fluid and Solid Rheology have been published. According to news reporting out of Timisoara, Romania, by VerticalNews editors, research stated, "In this paper, the magnetorheological (MR) and magnetoviscous properties of ferrofluid-based iron particle suspensions were investigated. The 2.1-A mu m mean size Fe particles were dispersed in high-concentration transformer oil-based ferrofluid, the iron particle volume fraction in the resulting nano-micro composite magnetorheological fluid samples varying from I broken vertical bar (Fe) = 5 to 40 %. The ferrofluid carrier has phi (p) = 23 % solid volume fraction of magnetic nanoparticles stabilized with chemisorbed oleic acid monolayer and without any excess surfactant."
Our news journalists obtained a quote from the research from Polytechnic University, "In the absence of the field, the ferrofluid has a quasi-Newtonian behavior with a weak shear thinning tendency. The static yield stress shows an increase of about 3 orders of magnitude for an iron particle content of approx. I broken vertical bar (Fe) = 25 % (I broken vertical bar (tot) = 42.25 %), while above this value, a saturation tendency is observed. The dynamic yield stress (Bingham model) also increases with the magnetic induction and the particle volume fraction; however, the saturation of the MR effect is less pronounced. The relative viscosity change has a maximum at I broken vertical bar (Fe) = (10-15) % due to the accelerated increase of the effective viscosity of the composite for higher Fe content."
According to the news editors, the research concluded: "Addition of micrometer-sized iron particles to a concentrated ferrofluid without any supplementary stabilizing agent proved to be a direct and simple way to control the magnetorheological and magnetoviscous behavior, as well as the saturation magnetization of the resulting nano-micro composite fluid to fulfill the requirements of their use in various MR control and rotating seal devices."
For more information on this research see: Yield stress and flow behavior of concentrated ferrofluid-based magnetorheological fluids: the influence of composition. Rheologica Acta, 2014;53(8):645-653. Rheologica Acta can be contacted at: Springer, 233 Spring St, New York, NY 10013, USA. (Springer - www.springer.com; Rheologica Acta - www.springerlink.com/content/0035-4511/)
Our news journalists report that additional information may be obtained by contacting D. Susan-Resiga, Univ Politehn Timisoara, Res Center Hydrodynam Complex Fluids, Timisoara, Romania.
Keywords for this news article include: Europe, Romania, Timisoara, Fluid and Solid Rheology
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