Which of the following is NOT a non-thermal method of drying?
Anonymous Quiz
3%
A) Expression of a solid
3%
B) Extraction of liquid using a solvent
2%
C) Adsorption of water using desiccants
93%
D) Heating the material
What is one purpose of drying in the pharmaceutical industry?
Anonymous Quiz
88%
A) In the preparation of granules in tablets and capsules
4%
B) To increase the weight of the material
3%
C) To promote bacterial growth
4%
D) To make materials less stable
How does drying aid in the preservation of animal and vegetable drugs?
Anonymous Quiz
1%
A) By increasing the weight of the material
8%
B) By promoting mold and bacterial growth
91%
C) By minimizing mold and bacterial growth
1%
D) By making the material less stable
What does psychrometry determine?
Anonymous Quiz
1%
A) The temperature of the material
98%
B) The vapor concentration and carrying capacity of the gas
1%
C) The weight of the material
0%
D) The stability of the material
What is the term for the concentration of water vapor in a gas?
Anonymous Quiz
11%
A) Vapor pressure
8%
B) Relative humidity
75%
C) Humidity
6%
D) Absolute humidity
🔥1👏1
On a psychrometric or humidity chart, what does the horizontal axis represent?
Anonymous Quiz
82%
A) Temperature
10%
B) Absolute humidity
4%
C) Pressure
4%
D) Relative humidity
What is the wet-bulb temperature?
Anonymous Quiz
5%
A) The temperature of the air
79%
B) The equilibrium of heat transfer between air and liquid
10%
C) The temperature of the liquid
6%
D) The temperature of the solid material
👏1
How is the wet-bulb temperature measured?
Anonymous Quiz
7%
A) Using an ordinary thermometer
87%
B) Using a thermometer with a bulb covered by a water-saturated wick
3%
C) By calculating the difference in vapor pressure
2%
D) By measuring the humidity of the gas
What is the dry-bulb temperature?
Anonymous Quiz
26%
A) The equilibrium of heat transfer between air and liquid
53%
B) The temperature of the air
4%
C) The temperature of the liquid
17%
D) The temperature of the solid material
👏1
What are the two main operations involved in drying?
Anonymous Quiz
5%
A) Heat and pressure transfer
2%
B) Mass and pressure transfer
88%
C) Heat and mass transfer
4%
D) Pressure and temperature transfer
What is the driving force for heat transfer in drying?
Anonymous Quiz
8%
A) Pressure differential
23%
B) Humidity differential
62%
C) Temperature differential
7%
D) Mass differential
👎1👏1
How can the rate of drying be accelerated? (Choose the incorrect option)
Anonymous Quiz
9%
A) By increasing the air flow rate
12%
B) By raising the inlet air temperature
66%
C) By reducing the air velocity
13%
D) By dehumidifying the inlet air
How is the wet-weight moisture content of a solid represented?
Anonymous Quiz
9%
A) Water content as a percentage of the weight of the dry solid
79%
B) Water content as a percentage of the weight of the wet solid
4%
C) Water content as a percentage of the weight of the air
8%
D) Water content as a percentage of the weight of the water
🔥2👏1
How is the Loss on Drying (LOD) calculated?
Anonymous Quiz
11%
A) [(wt of water in sample / wt of dry sample)] × 100
82%
B) [(wt of water in sample / wt of wet sample)] × 100
4%
C) [(wt of wet sample / wt of dry sample)] × 100
3%
D) [(wt of wet sample / wt of water in sample)] × 100
How is moisture content determined on a dry-weight basis?
Anonymous Quiz
4%
A) [(wt of water in sample / wt of wet sample)] × 100
87%
B) [(wt of water in sample / wt of dry sample)] × 100
7%
C) [(wt of wet sample / wt of dry sample)] × 100
2%
D) [(wt of wet sample / wt of water in sample)] × 100
❤1
In the study of drying rate, what is plotted as moisture content versus time?
Anonymous Quiz
30%
A) Drying rate vs moisture content
57%
B) Moisture content vs drying time
5%
C) Drying time vs temperature
8%
D) Temperature vs moisture content
👎3❤2🔥1👏1
In which period of the drying curve does the drying rate depend on the diffusion rate?
Anonymous Quiz
34%
A) Constant rate period
19%
B) First falling rate period
37%
C) Second falling rate period
10%
D) Equilibrium moisture period
When is continued drying considered a waste of time and energy?
Anonymous Quiz
4%
A) During the constant rate period
9%
B) During the first falling rate period
10%
C) During the second falling rate period
77%
D) After the equilibrium moisture period begins
Which type of solid is more difficult to dry?
Anonymous Quiz
8%
A) Crystalline solids
89%
B) Amorphous solids
2%
C) Solids with no pores
2%
D) Solids with large pores
❤2
What is the major criterion for classifying dryers based on method of sample handling?
Anonymous Quiz
25%
A) Heat sensitivity of the material
61%
B) Presence or absence of agitation
8%
C) Nature of the liquid to be removed
5%
D) Scale of operation