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Which among the following equation is related to diffusional mixing in liquid (during steady state)? (Where D, Cl, Cs, v represents the diffusivity in liquids, solute concentration of liquid and solid, constant rate and Cl’=dCl/dx respectively)

Correct Answer: –DCl = v(Cl-Cs)
Steady state itself gives an idea that the particular state should be balanced. Here in this case the rate at which the solute is rejected from the solidifying liquid should be balanced by the rate at which solute diffuses down the concentration gradient away from the interface. That is –DCl = v(Cl-Cs).

Estimate the interfacial solute concentration in the two liquids when the solute concentration is 45000 kg-moles/m3, interfacial solute concentration in liquid is 40000 kg-moles/m3, diffusivity is 2.5 × 10-11 m2/s and the length of the tube is 5m3 and the partition coefficient is 0.25.

Consider a given volume of liquid at a temperature T below Tm with a free energy G’. If some of the atoms of the liquid cluster together to form a small sphere of solid, the free energy of the system will change to G, given by________ (Assume V1 volume of the solid sphere, V2 volume of liquid, A is the solid/liquid interfacial area, γ solid/liquid interface free energy, G1 and G2 are the free energies per unit volume of solid and liquid respectively).

The concentration of oxygen at the inner surface of the vessel is maintained at a level C depending on the pressure in the vessel, while the concentration at the outer surface is reduced to zero by the escape of oxygen to the surroundings. A steady state will eventually be reached when the concentration everywhere reaches a constant value. Provided D is independent of concentration there will be a single concentration gradient in the wall and the thickness of the wall is L, the flux is given by________________

Which equation represents Grubler’s equation? (where “F”represents Degrees of freedom, n represents number of links, l represents Number of lower pairs, h represents Number of higher pairs)

The steady-state creep activation energy is given by the Arrhenius type rate equation ε = Ae-(Q/RT), where, Q = activation for rate-controlling step A = pre-exponent complex constant containing the frequency of vibration of the flow unit T = absolute temperature R = Universal gas constant The slope of the equation for log ε vs. log T plot will be equal to __________

In pure metals solidification is controlled by the rate at which the latent heat of solidification can be conducted away from the solid/liquid interface. Which among the following equation satisfies the heat flow and the interface stability? (Kl, Ks are respective thermal conductivities of liquids and solids, L the latent heat of fusion per unit volume, v growth rate).

If the volume of the solid sphere and the volume of the liquid is given as V1 and V2 respectively, G1 and G2 are the free energies per unit volume of solid and liquid respectively. The free energy of the system without any solid present is given by_______

How is the molar concentration of solute in stationary phase related to molar concentration of solute in the mobile phase?

200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, Nc = 0.5 × 10-3 kg/m2.s. The initial moisture content of the solid is 0.2 kg moisture/kg dry solid. The interfacial area available for drying is 4 m2/1000 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)

Which of the following statements are true/false?
1. A minimum rate of wages for the time spent by employees for the production of output is minimum time rate.
2. Minimum piece rate is the rate based on the quantity of the output employees have produced.
3. The guaranteed time rate is a minimum rate of remuneration to apply in the case of employees employed on piece work for the purpose of securing to such employees a minimum rate of wages on a time work basis.
4. A minimum rate of remuneration to apply in the case of employees employed on piece work for the purpose of securing to such employees a minimum rate of wages on a time work basis is overtime rate.