Post Harvest Unit Operations

• Threshing Cylinders for Fine Straw (Bhusa) Production:
• In Indian agriculture, wheat straw (bhusa) is heavily valued as dairy cattle fodder and must be bruised and crushed into fine pieces.
• The Hammer mill type (or syndicated beater type with serrated concave) threshing cylinder uses high-speed swinging/fixed hammers that pulverize and bruise wheat straw into exceptionally fine fodder.
• Rasp-bar and spike-tooth cylinders thresh grain effectively but produce coarser straw pieces.
• Conclusion: Hammer mill type (Option 2).

Correct option: (2) Hammer mill type

• Balancing of Mower Pitman Drives:
• Assertion (A): The rotating counterweight commonly provided on the flywheel of a mower pitman drive does not give complete balancing. $\implies$ True.
• rotating counterweight generates a centrifugal force in all radial directions ($360^\circ$), whereas the knife reciprocates linearly along a single horizontal axis; balancing the horizontal inertia force introduces an unbalanced vertical force.
• Reason (R): Inertia force of the knife varies as the square of crank speed and as the first power of stroke. $\implies$ True.
• For simple harmonic motion, maximum inertia force is $F_i = m \omega^2 r = m \omega^2 (S/2) \propto N^2 \cdot S$.
• Relationship: Reason (R) defines the magnitude of reciprocating inertia, while Assertion (A) stems from the directional mismatch between rotating counterweights and linear reciprocation.
• Conclusion: Both (A) and (R) are true but (R) is NOT the correct explanation of (A) (Option 2).

Correct option: (2) Both (A) and (R) are true but (R) is NOT the correct explanation of (A).

Matching the items of List I with List II for Storage environment and its interaction with stored product:

The correct combination is Option 2: (A) - (II), (B) - (Ill), (C) - (IV), (DB) - (1).

Correct option: (2) (A) - (II), (B) - (Ill), (C) - (IV), (DB) - (1)