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- Question
The viscosity of a fluid changes with either stirrer speed or mixing time. But when mixing ceases, the viscosity returns to its original state. This fluid is best described as
Options- A. newtonian
- B. rheopectic
- C. viscoelastic
- D. thixotropic
- Correct Answer
- viscoelastic
- 1. The medium will have the highest viscosity (considering that the cells do not secrete gums) with the presence of
Options- A. single celled bacteria
- B. filamentous fungi that form pellets
- C. filamentous fungi that grow as long poorly branched chains
- D. yeast Discuss
- 2. A pseudoplastic fluid is one in which the viscosity
Options- A. is constant regardless of the stirrer speed or mixing time
- B. changes during mixing but returns to its original state after mixing
- C. increases with increasing stirrer speed
- D. decreases with increasing stirrer speed Discuss
- 3. The SI unit for viscosity is
Options- A. kg.m-1.s-1
- B. kg.m-2.s-2
- C. kg.m-3.s-1
- D. kg.m-1.s-2 Discuss
- 4. In sparged mammalian cell bioreactors, the cell damage is caused because of
Options- A. shear stress arising during mixing of the cell culture fluid
- B. shear stresses arising from the breakup of bubbles at the liquid surface
- C. shear stresses between bubbles in foam at the liquid surface
- D. all of the above Discuss
- 5. A Brookfield viscometer measures viscosity by determining
Options- A. the shear stress
- B. the shear rate
- C. the shear stress and shear rate
- D. the torque required to move an impeller at a set speed Discuss
- 6. A liquid is flowing at 11,400 l.h-1 along a pipeline having a diameter of 4 cm. If the liquid has a density of 1 g.ml-1 and viscosity of 0.001kg.m-1.s-1, then the liquid would be in the
Options- A. laminar phase
- B. transient phase
- C. turbulent phase
- D. any of the phase Discuss
- 7. Bubble free aeration systems requires
Options- A. silicone tubing or gas permeable membranes to facilitate gas transfer
- B. carbon dioxide instead of air to supply oxygen
- C. silicone tubing or gas permeable membranes to remove carbon dioxide by oxygen in the form of hydrogen peroxide
- D. filled headspace of the reactor with carbon dioxide Discuss
- 8. If the viscosity of a fluid decreases with the length of time that it is being mixed, then this fluid is
Options- A. newtonian
- B. rheopectic
- C. viscoelastic
- D. thixotropic Discuss
- 9. A viscoelastic fluid is one in which the viscosity
Options- A. is constant regardless of the stirrer speed or mixing time
- B. changes during mixing but returns to its original state after mixing
- C. increases with increasing stirrer speed
- D. decreases with increasing stirrer speed Discuss
- 10. Which of the following is correct?
Options- A. The viscosity of liquids and gases decrease with increasing temperature
- B. The viscosity of liquids and gases increase with increasing temperature
- C. the viscosity of gases increases with increasing temperature, but decreases in liquids
- D. the viscosity of gases decreases with increasing temperature, but decreases in liquids. Discuss
Fluid Flow problems
Search Results
Correct Answer: filamentous fungi that grow as long poorly branched chains
Correct Answer: decreases with increasing stirrer speed
Correct Answer: kg.m-1.s-1
Correct Answer: shear stress arising during mixing of the cell culture fluid
Correct Answer: the torque required to move an impeller at a set speed
Correct Answer: turbulent phase
Correct Answer: silicone tubing or gas permeable membranes to facilitate gas transfer
Correct Answer: thixotropic
Correct Answer: changes during mixing but returns to its original state after mixing
Correct Answer: the viscosity of gases increases with increasing temperature, but decreases in liquids
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