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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Q. Larger propellers turn at the speed of

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Q. A microbial population in a suspension culture will only be limited by oxygen availability if the dissolved oxygen

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Q. Which of the following model holds correct for the two-film theory? (where KL is the mass transfer coefficient, DAB diffusivity and Zf film thickness)

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Q. Froude number is avoided in calculation of power requirements for low viscosity liquid mixing systems when

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Q. A fermentation system has a KLa of 3 s­¹ and a C0* of 5 ppm of O₂. If the bulk liquid is completely depleted of oxygen, then the oxygen transfer rate will be equal to

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Q. During fermentation, the saturation concentration of oxygen was reduced from 7 ppm. to 1 ppm. Which one of the following conclusions can be drawn?

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Q. If the stirrer speed is too slow, bubbles will accumulate and coalescese under the impeller. This phenomenon is known as a

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Q. The maximum solubility of the alkane in the medium is 5 ppm. If the actual dissolved concentration of the alkane in the medium is 1 ppm. what conclusion may be drawn?

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Q. Reynolds (Rei) number for the impeller is given by (where Di, stirrer diameter; N, stirrer speed, ρ, density of fluid and μ, viscosity of fluid)

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