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Slip effects on squeezing flow of nanofluid between two parallel disks

Das K., Jana S., Acharya N.

International Journal of Applied Mechanics and Engineering

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2016

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Vol. 21, no. 1

5--20

EN

In this study, the influence of temperature and wall slip conditions on the unsteady flow of a viscous, incompressible and electrically conducting nanofluid squeezed between two parallel disks in the presence of an applied magnetic field is investigated numerically. Using the similarity transformation, the governing coupled partial differential equations are transformed into similarity non-linear ordinary differential equations which are solved numerically using the Nachtsheim and Swigert shooting iteration technique together with the sixth order Runge-Kutta integration scheme. The effects of various emerging parameters on the flow characteristics are determined and discussed in detail. To check the reliability of the method, the numerical results for the skin friction coefficient and Nusselt number in the absence of slip conditions are compared with the results reported by the predecessors and an excellent agreement is observed between the two sets of results.

2

A two-layered blood flow model of Bingham type non-Newtonian fluid

Das K., Jana S.

International Journal of Applied Mechanics and Engineering

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2012

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Vol. 17, no. 1

17-26

EN

In the present paper, a two layered blood flow model through a cylindrical tube of a Bingham type non-Newtonian fluid is considered. The relative coefficients of viscosity for peripheral and core layer are determined and their nature is shown graphically for different values of the maximum hematocrit, shape parameter, etc.

3

Unusual visible absorption in high PbO lead borate glass

Jana S., Karmakar B., Kundu P.

Materials Science Poland

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2007

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Vol. 25, No. 4

1127--1134

EN

A series of glasses in the system xPbOź(100 - x)B2O3 (x = 45, 55, 65 mol %) were prepared using analytical grade PbO consisting of a mixture of orthorhombic and tetragonal phases (ca. 1:1, w/w) and H3BO3 melted in silica beaker in the temperature range of 575-900 oC for 30 min under normal atmosphere. Only the 55PbOź45B2O3 glass prepared at 575 (L2), 650 (L3) and 700 oC (L4) showed several optical absorption bands in the visible region. However, all the bands disappeared either when a 1.7 mol % equivalent PbO from Pb3O4 was added in the batch or the melting temperature was increased to more than 800 oC. L2 glass showed a broad absorption band at ca. 485 nm which was thought to be due to combined effect of nanometallic lead (Pb0) and Pb+. The formation of hexagonal nano-Pb0 particles of 7-13 nm size in 55PbOź45B2O3 glass melted at 575-700 oC was confirmed by TEM and Pb+ was identified by a broad EPR signal with g-value at ca. 2.00. Optical absorption at ca. 485 nm and 565 nm (broad shoulder) was observed in L3 glass whereas a new peak at ca. 525 nm appeared in L4 which was identified due to Pb3+ by EPR signal with g-value ca. 2.176 and A-tensor, ca. 6340×10-4 cm-1. A mechanism for the formation of Pb0, Pb+ and Pb3+ has been proposed.

4

Quantum confinement effect of in-situ generated Cu2O in a nanostructured zirconia matrix

Kundu S., Jana S., Biswas P. K.

Materials Science Poland

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2005

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Vol. 23, No. 1

7--14

EN

The incorporation of Cu2+ in zirconyl chloride octahydrate sol or solution was used as a precursor for dip coating. This resulted in the in-situ formation of nanostructured Cu2O quantum particles in the zirconia matrix. The size-dependent properties of the Cu2O quantum particles were observed when the films were annealed in the range of 200-600°C. A red shift of the UV band, ascribed to the transition from the copper d-shells to higher sublevels of the conduction band, was observed in the range of 260-315 nm due to an increase in the nanocrystallite size with increasing annealing temperature. Three types of emissions, blue, green, and yellow, were observed in films of relatively high thickness (around 120-130 nm) due to Wannier-like excitonic transitions. For films of relatively low thickness (50-70 nm) only green emission was observed. From lifetime measurements of samples annealed at 450°C it may be concluded that the short decay time is bi-exponential in character from ns to ps with the chi-square value of 1.005, which is due to the confinement of Cu2O quantum particles.