Browsing by Author "Kumara, H."

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    A study on magnetorheological and sedimentation properties of soft magnetic Fe58Ni42 particles
    (Elsevier B.V., 2022) Aruna, M.N.; Rahman, M.R.; Joladarashi, S.; Kumara, H.; Meena, S.S.; Sarkar, D.; Umesh, C.K.
    In this study, the samples with two volume fractions (ϕ) of Fe58Ni42 (permalloy) i.e. (ϕ1 = 25 and ϕ2 = 30 %) were used as magnetic particles, silicone oil as a carrier fluid, and aluminium disterate as an additive. As received Fe58Ni42 particles surface morphology and composition of the Fe58Ni42 were investigated using field emission scanning electron microscopy (FESEM) coupled with energy dispersive spectroscopy (EDS), respectively. The X-ray Diffraction (XRD) structural information analysis confirmed Fe58Ni42 particles have a face-centered cubic phase, corresponding with the result of the high resolution transmission electron microscopy (HRTEM) characterization technique. The magnetorheological properties were tested via rotational rheometer at four different magnetic field strengths. The results show that sample PMRF-30 has a maximum shear stress, shear viscosity, and dynamic modulus greater than the PMRF-25 sample. In addition, experimental shear stress flow curves are well fitted with Herschel-Bulkley rather than Bingham and Casson rheological models. The permalloy based magnetorheological fluid (PMRF) samples were prepared with a 25 % volume fraction and a 30 % volume fraction of permalloy particles with a sample abbreviation of PMRF-25 and PMRF-30, respectively. Furthermore, the sedimentation stability of suspensions of both the samples was observed using visual inspection. This method result shows the sedimentation ratio with respect to time of 72 h was 31 % and 29 %, respectively. © 2022 Elsevier B.V.
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    Investigating Sedimentation and Rheological properties of Magnetorheological Fluids using various carrier fluids
    (2019) Aruna, M.N.; Rahman, M.R.; Joladarashi, S.; Kumara, H.
    The present paper focuses on the preparation of Magnetorheological (MR) fluids samples with three types of carrier fluids are silicone, light paraffin and Poly-alpha-olefin (5, 30 and 400 cSt) viscosity oils with 25% volume fraction of carbonyl iron particles and 3% fumed silica as a thixotropic agent to improve sedimentation of the MR fluid. The morphology, magnetic saturation and phase of the carbonyl iron particles were investigated using field emission scanning electron microscopy (FESEM), super quantum interface interference device (SQUID), X-ray diffraction (XRD) respectively. The results found that obtained powder particles spherical in shape, and a high magnetic saturation of 270 (emu/gm) with the applied field of 15000 (Oe). The prepared MR fluids rheological properties were tested using Anton Paar MCR702 Twin drive rheometer fitted with a magneto-rheological module. Sedimentation stability examined using direct observation method. � Published under licence by IOP Publishing Ltd.
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    Investigating Sedimentation and Rheological properties of Magnetorheological Fluids using various carrier fluids
    (IOP Publishing Ltd, 2019) Aruna, M.N.; Rahman, M.R.; Joladarashi, S.; Kumara, H.
    The present paper focuses on the preparation of Magnetorheological (MR) fluids samples with three types of carrier fluids are silicone, light paraffin and Poly-alpha-olefin (5, 30 and 400 cSt) viscosity oils with 25% volume fraction of carbonyl iron particles and 3% fumed silica as a thixotropic agent to improve sedimentation of the MR fluid. The morphology, magnetic saturation and phase of the carbonyl iron particles were investigated using field emission scanning electron microscopy (FESEM), super quantum interface interference device (SQUID), X-ray diffraction (XRD) respectively. The results found that obtained powder particles spherical in shape, and a high magnetic saturation of 270 (emu/gm) with the applied field of 15000 (Oe). The prepared MR fluids rheological properties were tested using Anton Paar MCR702 Twin drive rheometer fitted with a magneto-rheological module. Sedimentation stability examined using direct observation method. © Published under licence by IOP Publishing Ltd.