Podcast
Questions and Answers
Why is it important to have an accurate estimate of the physical properties of grains?
Why is it important to have an accurate estimate of the physical properties of grains?
- To solve problems related to heat and mass transfer
- To design scientific machines and structures for crop production
- For efficient handling, processing, and storage of crops
- All of the above (correct)
The physical properties of grains have no influence on their market value.
The physical properties of grains have no influence on their market value.
False (B)
Name three physical properties of grains that are considered engineering parameters of a product.
Name three physical properties of grains that are considered engineering parameters of a product.
Shape, size, volume
Variations in paddy grain length are attributed to differences in the length of the awn and the ______.
Variations in paddy grain length are attributed to differences in the length of the awn and the ______.
What distinguishes 'Extremely Long' type paddy from 'Long' type paddy?
What distinguishes 'Extremely Long' type paddy from 'Long' type paddy?
The surface area of paddy grain is considered a perfect sphere for design purposes.
The surface area of paddy grain is considered a perfect sphere for design purposes.
According to ISO standards, what L/W ratio defines 'Slender' shaped paddy?
According to ISO standards, what L/W ratio defines 'Slender' shaped paddy?
The measurement of axial dimensions involves determining the maximum area (a and b axes) and the ______ area (c axis) of a grain sample.
The measurement of axial dimensions involves determining the maximum area (a and b axes) and the ______ area (c axis) of a grain sample.
Which physical properties are most important in designing equipment for cleaning and separating grains?
Which physical properties are most important in designing equipment for cleaning and separating grains?
Charted standards for describing grain shape eliminate variations in assessment by different observers.
Charted standards for describing grain shape eliminate variations in assessment by different observers.
Name two applications where the physical properties of grains are crucial.
Name two applications where the physical properties of grains are crucial.
Heat and mass transfer problems during grain are solved using knowledge of physical properties.
Heat and mass transfer problems during grain are solved using knowledge of physical properties.
A rice particle is considered 'large broken milled grain' if has which length?
A rice particle is considered 'large broken milled grain' if has which length?
Angle of repose has no relevance in the design of storage facilities for grains.
Angle of repose has no relevance in the design of storage facilities for grains.
What instrument is used to trace the projection of a grain sample to measure its axial dimensions?
What instrument is used to trace the projection of a grain sample to measure its axial dimensions?
The shape of a grain can be defined using standard charts, either with a number on the chart or using ______.
The shape of a grain can be defined using standard charts, either with a number on the chart or using ______.
What does the 'coefficient of friction' of grains relate to?
What does the 'coefficient of friction' of grains relate to?
Husk density is constant regardless of how tightly it is packed.
Husk density is constant regardless of how tightly it is packed.
Give an example of how surface area impacts handling of grains.
Give an example of how surface area impacts handling of grains.
According to definition of terms, a rice particle that can pass through a sieve with round perforation of 1.4 mm diameter is called ______
According to definition of terms, a rice particle that can pass through a sieve with round perforation of 1.4 mm diameter is called ______
Match the following:
Match the following:
What is the typical percentage range that husks contribute to the overall weight of paddy?
What is the typical percentage range that husks contribute to the overall weight of paddy?
The calorific value of husks is negligible and makes them unsuitable for use as a fuel source.
The calorific value of husks is negligible and makes them unsuitable for use as a fuel source.
What is the typical free load density of husks?
What is the typical free load density of husks?
For scientific designs of machines and structure for production, handling, processing, and ______ of crops estimation of physical properties of grains is important.
For scientific designs of machines and structure for production, handling, processing, and ______ of crops estimation of physical properties of grains is important.
Flashcards
Importance of physical properties of grains
Importance of physical properties of grains
Studying these properties helps accurately estimate shape, size, volume, specific gravity, and surface area, crucial for engineering parameters.
Paddy grain length
Paddy grain length
The length of the paddy grain varies based on the length of its awn and pedicel.
Types of paddy by length
Types of paddy by length
Extremely Long: ≥7.5 mm; Long: ≥6.5 but < 7.5 mm; Medium: ≥5.5 but < 6.5 mm; Short: < 5.5 mm
Length/Width ratio types
Length/Width ratio types
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Charted Standards
Charted Standards
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Importance of surface area
Importance of surface area
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Definition of head rice grain
Definition of head rice grain
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Brewer's rice
Brewer's rice
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Small brokens
Small brokens
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Bulk density
Bulk density
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Angle of repose
Angle of repose
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Coefficient of friction
Coefficient of friction
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Study Notes
Importance of Physical Properties of Grains
- Considering bulk or individual units is important when studying grain's physical properties.
- Accurate estimates of shape, size, volume, specific gravity, and surface area is important.
- Physical characteristics can be considered as engineering parameters.
- These are important for scientific designs of machines and structures for:
- Production
- Handling
- Processing
- Storage of crops
- They are necessary for solving problems related to heat and mass transfer:
- Grain storage
- Drying
- Aeration
- Refrigeration, and processing.
- Physical properties dictates market value.
Physical Properties
- Moisture Content
- Size
- Shape
- Surface Area
- Porosity
- Bulk Density
- Angle of Repose
- Angle of Friction
Product Dimension and Structure
- Paddy grain length varies due to variations in the length of the awn and pedicel.
Types of Paddy by Length
- Extremely Long: ≥7.5 mm
- Long: ≥6.5 but <7.5 mm
- Medium: ≥5.5 but <6.5 mm
- Short: <5.5 mm
- Measurements are based on 80% of the whole brown rice.
Length/Width Ratio of Whole Brown Rice
- Slender: ≥ 3.0
- Bold: ≥ 2.0 but <3.0
- Round: < 2.0
Length/Width Ratio of Paddy
- Classification is based on the International Organization for Standardization (ISO).
- Scale 1: Slender, L/W ratio over 3.0
- Scale 3: Medium, L/W ratio 2.1 - 3.0
- Scale 5: Bold, L/W ratio 1.1 - 2.0
- Scale 9: Round, L/W ratio 1.0 or less
Shape and Size Measurement
- Shape and size are inseparable in a physical object.
- Both are required to satisfactorily describe the object.
- Defining shape involves measuring dimensional parameters.
- Charted Standards:
- Longitudinal and lateral cross-sections compared to charted standards.
- Shape can be defined by number on the chart or descriptive terms.
- This technique is simple but subjective, influenced by personal prejudice.
- Different observers can achieve different results.
- Requires elaborate precautions and experienced observers.
Measurement of Axial Dimensions
- The outline of the projection of each sample can be traced using a photographics enlarger.
- Place seed on the plane with the negative positioned to maximize shadow area.
- Maximum area (a and b axes) and minimum area (c axis) are measured.
Surface Area
- The surface area of paddy grain, shaped like cono-elliptical cylinders, affects physical properties.
- It impacts on the porosity, angle of repose, and angle of friction.
- It is important in designing, cleaning, and separating equipment, as well as dryer and storage facilities.
Definitions of Terms
- Head rice grain: Rice particle with length of 6/8 or more of the whole unbroken milled rice kernel.
- Large broken milled grain: Rice particle with a length of 3/8 or more but shorter than 6/8.
- Brewer's rice: Rice particles passing through a sieve with 1.4 mm round perforation.
- Small brokens: Particles not passing through a sieve with 1.4 mm round perforation but shorter than 3/8.
Mass Properties
- Bulk density is 576 kg/m³.
- Voids, air space: 48%
- Kernel specific gravity is 1.11.
- Angle of repose is 36°.
- Coefficient of friction:
- Smooth steel: 0.41
- Finished concrete: 0.52
- Smooth wood: 0.44
- Husk density:
- Well packed: 128 kg/m³
- Loosely packed: 117 kg/m³
- Husks represent 20% to 24% of the weight of paddy.
- The free load density of husks is about 125 kg/m³.
- The calorific value of husks varies from 3000 to 3500 Kcal.
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Description
Explore the significance of grains' physical properties, including moisture, size, shape and bulk density. Learn how these characteristics influence everything from storage and processing to market value. Understand paddy grain dimensions and structural variations.
