Q. The rate limiting step in the movement of oxygen from the gas phase in a bubble to the cell is the movement of oxygen molecules through

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Q. Penetration theory assumes that turbulent eddies travel from the bulk of the phase to the interface where they remain constant for a constant exposure time (te). The model correlating KL, mass transfer coefficient and DAB, diffusivity can be expressed as

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Q. The oxygen uptake requirements of a microbial population is characterized by the following parameters: μm = 0.2 h­¹, K0 = 0.2 mg O₂.l­¹, Y0 = 0.5 mg dry weight/mg O₂ and C0,crit=0.8 mg.l­¹ The required concentration of cells is 1000 mg.l­¹ and the saturation oxygen concentration of the medium is 5.8 mg.l­¹. The required KLa must be greater than

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Q. Which have the maximum resistance while transferring carbon dioxide from the bulk liquid to an air bubble?

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Q. If liquid density and viscosity remains constant, then the Reynolds number in a stirred tank reactor will vary with the

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Q. Power number is ratio of

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Q. The volume of liquid (VL) in a cylindrical reactor can be calculated from the liquid height (HL) and tank diameter (Dt) using the following equation

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Q. The average fractional gas hold up (H) can be given as (where Zf and Zl are the level of aerated and clear liquid respectively)

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Q. Which of the following(s) is/are non-mechanically agitated reactors?

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Q. Which of the following best explains the reasons for using axial flow impellers in crystallization and precipitation reactions?

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Q. When the height of an aerated bioreactor is increased, it will increase the oxygen transfer rate by

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Q. Which of the following is correct for the off-centre impellers?

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Q. The power required by an impeller in a gas sparged system compare to the power required by impeller operating at same speed in a gas free liquid is usually

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Q. Which of the following stirrer requires least amount of energy for same yield?

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Q. A reactor has a total volume of 50,000 litres. If it has a headspace volume of 10,000 litres, then volume of liquid in the reactor will be

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Q. A cylindrical reactor fitted with Rushton Turbine has a liquid volume of 100,000 litres. It has an aspect ratio (the ratio of the channel height to the width) of 2:1. The diameter of the impeller should be approximately:

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Q. In the bubble boundary layer, oxygen concentration can be determined by measuring

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Q. Impeller damage can be minimized by

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Q. To increase the oxygen transfer rate in a shake flask culture system, which of the following (s) is/are followed?

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Q. What is/are the major difference(s) between disc and turbine type stirrer?

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