Step-by-step fan power calculation:

• Air Power (Output power required to move air):
  \[ P_{\text{air}} = Q \times \Delta P \]
  Where:
  • Flow rate, \(Q = 2\text{ m}^3/\text{s}\) - Static pressure, \(\Delta P = 375\text{ Pa} = 375\text{ N/m}^2\) \[ P_{\text{air}} = 2 \times 375 = 750\text{ Watts} \]

• Input Power required by the fan motor:
  \[ P_{\text{input}} = \frac{P_{\text{air}}}{\eta} = \frac{750\text{ W}}{0.75} = 1000\text{ Watts} \]

Freeze Drying (Lyophilization) preserves food through a two-step mechanism:

• The product is rapidly frozen to convert free water into ice crystals.
• In a high-vacuum drying chamber operating below the triple point of water (611.7 Pa), gentle heat is applied so that ice transforms directly into water vapor without passing through the intermediate liquid phase. This physical phase change is called Sublimation.

The LSU (Louisiana State University) Dryer is the most widely used continuous mixed-flow grain dryer in Indian commercial modern rice mills:
It consists of a tall rectangular vertical column containing multiple horizontal rows of inverted V-shaped sheet-metal air ducts (ports) arranged in an alternating, offset staggered pattern.
Alternate rows function as air inlet ducts (delivering hot drying air) and exhaust air ducts, ensuring uniform mixing and cross-flow drying of descending grain without excessive temperature gradients.

Detailed Matching of Drying Kinetics and Psychrometric Terms:

• Falling rate period matches with (III) Equilibrium moisture content: During falling rate drying, the drying rate progressively decreases as moisture diffuses from grain interior, asymptotically approaching the equilibrium moisture content (EMC).
• Absolute humidity (Humidity ratio) matches with (IV) Ratio of kg of water vapour in kg of dry air ($W = m_v / m_a$).
• Percent humidity (Percentage saturation) matches with (I) Ratio of actual humidity ratio to the saturation humidity ratio at the same temperature, expressed as a fraction or percentage ($W / W_s \times 100$).
• Constant rate period matches with (II) Critical moisture content: The constant rate drying period ends at the critical moisture content, where surface moisture is exhausted and internal diffusion becomes rate-limiting.