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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Q. The advantage of axial flow impellers over radial flow impellers is that axial flow impellers

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Q. Pure oxygen, if used instead of air will increase oxygen transfer rates because

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Q. For aerated mixing vessels in an aqueous solution, the mass transfer coefficient (kL) co-relating power consumption (Pm) and fermenter volume (V) can be expressed as

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Q. Higher temperatures affect oxygen transfer rates by

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Q. The Intermig impeller is

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Q. Main reason for using baffles in stirred tank reactors are

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