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Bhāvnagar, India

We review here, our work on the light scattering by ferrofluids and mixture of ferrofluids and other nonmagnetic suspensions subjected to an external static magnetic field. Detailed derivation of extinction coefficients of the systems when incident light is propagating along transverse and longitudinal direction of the field are carried out. In case of inclusion of anisotropic diamagnetic micron sized particles in a ferrofluids, effects of'magnetic holes' generated in the system on the extinction are discussed. The present work is analyzed in light of other similar investigations. It is shown that the study of polarization dependence of extinction coefficients in transverse field configuration is useful to arrive at an unambiguous conclusion regarding chain formation in a ferrofluid. © 2013 Elsevier B.V. All rights reserved. Source

Patel R.,Bhavnagar University
Journal of Magnetism and Magnetic Materials | Year: 2011

Mechanism of structure formation in bidispersed colloids is important for its physical and optical properties. It is microscopically observed that the mechanism of chain formation in magnetic nanofluid based magnetorheological (MR) fluid is quite different from that in the conventional MR fluid. Under the application of magnetic field the magnetic nanoparticles are filled inside the structural microcavities formed due to the association of large magnetic particles, and some of the magnetic nanoparticles are attached at the end of the chains formed by the large particles. The dipolar energy of the large particles in a magnetic nanofluid matrix becomes effective magnetic permeability (μeff) times smaller than that of the neutral medium. Inclusion of magnetic nanoparticles (∼10 nm) with large magnetic particles (∼35 μm) restricts the aggregation of large particles, which causes the field induced phase separation in MR fluids. Hence, nanofluid based MR fluids are more stable than conventional MR fluids, which subsequently increase their application potentiality. © 2010 Elsevier B.V. All rights reserved. Source

Maniya K.D.,Veer Narmad South Gujarat University | Bhatt M.G.,Bhavnagar University
International Journal of Production Research | Year: 2011

The objective of this research is to develop and implement a new methodology for multi-attribute selection of automated guided vehicle (AGV) for the material handling. The present paper proposes a modified grey relational analysis (M-GRA) method combined with analytical hierarchy approach (AHP). AHP method is used to assign the relative importance between AGV selection attributes and M-GRA method is applied to determine AGV selection utility index. A proposed AHP/M-GRA technique is more suitable for the decision-making in the presence of vagueness. The methodology is illustrated by means of an example. The study was followed by the validation and the sensitivity analysis of the AHP/M-GRA technique. The results of the study build confidence in suitability of AHP/M-GRA technique for selection of AGV alternatives. © 2011 Taylor & Francis. Source

Maniya K.D.,Veer Narmad South Gujarat University | Bhatt M.G.,Bhavnagar University
Computers and Industrial Engineering | Year: 2011

In the present work, a systematic and an alternative multiple attribute decision making methodology is presented for selection of facility layout design selection problems. The proposed methodology is based on Preference selection index (PSI) method. In the proposed methodology appropriate facility layout design is selected for a given application without considering relative importance between facility layout design selection attributes. Two different types of facility layout design selection problems are examined to demonstrate, validate, and to check the reliability of proposed methodology. In addition, subjective cost benefit analysis is performed to study the benefits to cost to the company. Finally, the study has concluded that the facility layout design selection methodology based on PSI method is simple, logical, and more appropriate for solving the facility layout design selection problems. © 2011 Elsevier Ltd. All rights reserved. Source

In this article, we have described the conventional and microwave method for the synthesis of 1-[2-(2-chloro(3-quinolyl))-5-(4-nitrophenyl)(1,3,4- oxadiazolin-3-yl)]-3-(aryl)prop-2-en-1-ones (4a-l). Through this method, we have achieved reduction in reaction time and better yield than the previously described conventional method. The application of microwave irradiation (MWI) is used for carrying out chemical transformations which are pollutionfree and eco-friendly. The structure of the compounds was characterized by spectral data. These compounds (4a-l) were evaluated for their in vitro antimicrobial screening on different strains of bacteria and fungi. © Springer Science+Business Media, LLC 2011. Source

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