ICAR AIEEA-PG — Agricultural Engineering & Technology (Major Subject Group 10) · India · National Testing Agency for ICAR
Original practice questions written to the published syllabus · not past papersStoring grain and produce safely, the loads it puts on bins and silos, and the conveyors and packages that move and protect it.
In the exams: GATE AG Section 6 (bin/silo pressure in 6 of 8 papers 2019–26); ICAR AICE subject 41 Units 6–7; NCEES PE (ANSI/ASAE S433 supplied); ASRB NET ASPE
ICAR AIEEA-PG — Agricultural Engineering & Technology
Unit VI (storage) asks recall and short calculation: primary and secondary storage insects, safe moisture, CAP storage and godown design features, Janssen and Rankine relations, aeration versus drying, phosphine chemistry, CA and MA definitions, packaging polymers and their barrier properties, and conveyor types.
How our questions for ICAR AIEEA-PG spread across the units of Storage Engineering, Material Handling & Packaging. Difficulty: 38 easy, 15 medium, 8 hard.
| Janssen's and Airy's theories of bin pressure | 11 | |
| Causes of storage losses | 8 | |
| Design of conveyors and elevators | 7 | |
| Packaging materials: paper, plastics and laminates | 6 | |
| Bag and bulk storage | 5 | |
| Godowns and warehouses | 4 | |
| Aeration of stored grain | 4 | |
| Bins and silos | 3 | |
| Warehouse management | 3 | |
| Barrier properties of packages | 3 | |
| Packaging machines | 3 | |
| Fumigation | 2 | |
| Controlled and modified atmosphere storage | 2 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
What is the purpose of dunnage beneath bag stacks?
B. To keep bags off a floor that transmits ground moisture and allow air below the stack
Dunnage (wooden crates, pallets or polythene sheet) separates the bottom bags from the floor, which may transmit moisture. It does not stabilise the stack by weight or release chemicals.
Further reading: Sahay and Singh, Unit Operations of Agricultural Processing
What is the maximum (limiting) lateral pressure that wheat of bulk density 780 kg/m³ can exert on the wall of a very deep 8 m diameter bin with a wall friction coefficient of 0.45?
A. 34.0 kPa
L_max = γR/μ′ with γ = 780 × 9.81 = 7.652 kN/m³ and R = D/4 = 2.0 m: 7.652 × 2.0/0.45 = 34.0 kPa. It does not depend on k. Using kg/m³ instead of weight density gives 3.47; using the radius D/2 instead of the hydraulic radius gives 68.0; multiplying by μ′ (6.89) is an algebra slip.
Further reading: Sahay and Singh, Unit Operations of Agricultural Processing
For grain with φ = 30°, above what grain depth does a 4 m wide bin become a deep bin by the plane-of-rupture criterion?
D. 6.93 m
Critical depth = D·tan(45° + φ/2) = 4 × tan60° = 6.93 m. Using tan(45° − φ/2) gives 2.31 m; ignoring φ (tan45°) gives 4.00 m; using the radius instead of the width gives 3.46 m.
Further reading: Sahay and Singh, Unit Operations of Agricultural Processing
A shallow bin holds grain of specific weight 7.5 kN/m³ to a depth of 3 m; φ = 30°. By Rankine's theory, what is the total lateral force per metre length of wall?
C. 11.25 kN/m
P = γH²k/2 = 7.5 × 3² × 0.333/2 = 11.25 kN/m, acting at H/3 = 1 m above the base. Forgetting the ½ (area of the triangle) gives 22.50; forgetting k treats grain as a liquid (33.75); γHk = 7.50 kPa is the pressure at the base, not the force.
Further reading: Sahay and Singh, Unit Operations of Agricultural Processing
By Rankine's theory, the resultant lateral force on the wall of a shallow bin with a level grain surface acts at
C. One third of the grain depth above the base
The pressure increases linearly from zero at the surface to γHk at the base, a triangular diagram whose centroid is H/3 above the base. H/2 would apply to a uniform pressure.
Further reading: Sahay and Singh, Unit Operations of Agricultural Processing
Arrange corrugated board flutes from tallest to shortest.
C. A > C > B > E
A flute is the tallest, then C, then B, then E (fine flute). Letters were assigned in the order of introduction, not size, which is why C sits between A and B.
Further reading: Robertson, Food Packaging: Principles and Practice
The double seam is the method of
B. Attaching the end to a metal container body
In a double seam the can-end curl and the body flange are interlocked and compressed in two rolling operations. Pouches are heat-sealed and bags sewn.
Further reading: Robertson, Food Packaging: Principles and Practice
A bucket elevator has buckets of 2 L capacity, 80% filled, spaced 0.3 m apart on a belt running at 2.5 m/s, handling grain of bulk density 750 kg/m³. Capacity?
C. 36.0 t/h
Buckets per second = v/spacing = 2.5/0.3 = 8.333. Mass per bucket = 0.002 m³ × 0.8 × 750 = 1.20 kg. Mass flow = 1.20 × 8.333 = 10.00 kg/s = 36.0 t/h. Ignoring the fill fraction gives 45.0; reporting kg/s as t/h gives 10.0; multiplying by spacing instead of dividing gives 3.24.
Further reading: Sahay and Singh, Unit Operations of Agricultural Processing
How does inclining a screw conveyor affect its capacity at constant speed?
D. Capacity falls
As the angle increases, material falls back over the flight and the loading efficiency drops, so capacity falls.
Further reading: Sahay and Singh, Unit Operations of Agricultural Processing
Which conveyor type is best for lifting grain vertically in a compact footprint?
C. Bucket elevator
Bucket elevators lift vertically; belts, horizontal chain and vibratory conveyors move material horizontally or at modest inclines.
Further reading: Sahay and Singh, Unit Operations of Agricultural Processing
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