Process Equipment Design

• Classification of Thick vs. Thin Shell Pressure Vessels:
• In structural mechanics, cylindrical pressure vessels are classified by the ratio of internal diameter to wall thickness ($D/t$):
• Thin shells: $D/t \ge 10 - 20$, where radial stress is negligible and membrane hoop stress is uniform.
• Thick shells: Lamé's equations apply due to pronounced non-uniform stress distribution across the thick wall.
• Official Answer Key: Designated Option 2 (>10) as the credited option.
• Conclusion: >10 (Option 2).

Correct option: (2) >10

• Design Foundations of Pressure Vessels:
• Elastic Analysis Basis:
• Design codes (ASME Boiler & Pressure Vessel Code Section VIII and IS 2825) formulate allowable design stresses based primarily on linear elastic analysis.
• Ensures that operating membrane and bending stresses remain strictly within the reversible Hookean elastic regime well below the material yield strength ($S_y$).
• Conclusion: Elastic analysis (Option 1).

Correct option: (1) Elastic analysis

• Ante-Mortem Disease Diagnosis in Lairage:
• Clinical Lairage Examination:
• Performed within 24 hours of slaughter while animals are alive to detect systemic and zoonotic clinical infections.
• Rabies is readily diagnosed ante-mortem through acute neurological manifestations: behavioral aggressiveness, aimless wandering, excessive salivation, ataxia, abnormal bellowing, and hindquarter paralysis.
• Conversely, cirrhosis is diagnosed only post-mortem upon visceral liver slicing, and tuberculosis/brucellosis require serological testing or carcass lymph node examination.
• Conclusion: Rabies (Option 4).

Correct option: (4) Rabies