Watershed Hydrology

• Objectives and Functions of Blanching:
• Blanching is a mild hydrothermal pre-treatment (hot water at 85–95°C or steam) for fruits and vegetables:
• Inactivation of enzymes: Inactivates polyphenol oxidase, catalase, and peroxidase to prevent browning and nutrient loss.
• Softening of tissue: Expels intercellular air and softens cell structure to facilitate packaging into cans.
• Cleaning of raw material: Removes adhering surface dust and reduces initial microbial load.
• (B) Killing of pathogenic microbes: Blanching does not achieve commercial sterility or complete destruction of spores; full thermal processing is performed later.
• Conclusion: Major functions include (A), (C) and (D) only (Option 3).

Correct option: (3) (A), (C) and (D) only.

• Glazing in Rice (Paddy) Milling:
• Glazing is a finishing process in polished rice production where milled rice grains are treated with a mixture of glucose and talc or paraffin in a glazing drum to impart a glossy, translucent sheen and protect against insect attack.
• Glazing is exclusively associated with Paddy (Rice) processing.
• Conclusion: Related to Paddy (Option 1).

Correct option: (1) Paddy

• Forces on Gang of Disc Harrows:
• Assertion (A): Concave end of the disc harrow gang tends to penetrate more deeply than the convex end. $\implies$ True.
• The soil side forces acting on disc faces create a couple that tilts the gang, causing the outer concave end to dig in deeper while the convex end tends to ride out of the soil.
• Reason (R): The radial force, which includes the vertical support force on the disc blade, must pass slightly to the rear of the disc centerline. $\implies$ True.
• Due to soil resistance and forward travel velocity, the resultant radial reaction shifts slightly rearward of the vertical center axis.
• Relationship: Reason (R) describes longitudinal force line of action on an individual blade, but does not provide the causal explanation for gang-level moments across the width.
• 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).

• Grain Storage Silo Classifications (Deep vs. Shallow Bins):
• Statement (I): In a deep bin, plane of rupture strikes the opposite side of structure before it meets the grain surface. $\implies$ True.
• In deep grain bins, the internal plane of rupture of the granular mass intersects the opposite vertical wall before reaching the top free surface of the grain.
• Statement (II): A grain bin can be classified as deep bin when the depth of grain is greater than the equivalent diameter. $\implies$ True.
• By Janssen and Airy criteria, a bin is classified as a deep bin when grain depth $H \gt D \tan(45^\circ + \phi/2) \approx D$.
• Conclusion: Both Statement (I) and Statement (II) are true (Option 1).

Correct option: (1) Both Statement (I) and Statement (II) are true.