Defects in Timber - vk

Defects occurring in timber are grouped into following five divisions.

1. Defect due to Conversion

Chip mark Diagonal grain Torn grain Wane

2. Defects due to fungi

Blue stain Dry rot Brown rot Heart rot Sap stain Wet rot White rot

3. Defects due to natural forces

Burls callus Chemical stain Coarse grain Dead wood Druxiness Foxiness Knots Rind galls Shakes Twisted fibres Upsets Water stain Wind cracks

4. Defects Due to seasoning

Bow Check Cup Warp Split Twist Radial Shakes Honey combing collapse Case hardening

5. Insects that cause defects

Beetles Termites Marine borers

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Clamp burning and Kiln burning comparison - vk

 Comparison between Clamp buring and Kiln burning 

No. item	Clamp-burning	Kiln burning
Capacity	About 20000-100000	avg 25000
Cost of fuel	Low as grass, cow dung, litter may be used	High because of coal dust is to be used
Initial cost	Very low as no structures are to be built	More as permanent structures are to be constructed
Quality of bricks	The percentage of good qualtiy bricks is small about 60%	Percentage of good quality bricks is high 90%
Regulation of fire	It is not possible to control or regulate fire during the process of buring.	The fire is under control throughout the process of burning
Skilled supervision	Not necessary through out the process of burning	The continuous skilled supervision is necessary
Structure	Temporary structure	Permanent structure
Suitability	For small scale	For large scale
Time of burning and cooling	It requires about 2-6 months	Actual burning times is 24 hr. and 12 days are required for cooling of bricks.

Notes - About comparison is based on use of these kiln with respect to bricks.

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Bull's trench and Hoffman's kiln comparison - Bricks vk study

 Comparison between Bull's trench and Hoffman's kiln

No. Items	Bull's trench kiln	Hoffman's kiln
Burning Capacity	About 3 lakhs in 12 days.	About 40 lakhs in one season
Continuity of working	It stops functioning during mansoon as it is not provided with a permanent roof	It functions all the year with permanent roof.
Cost of fuel	High as consumptions of fuel is more.	Low
Drying space	It requires more space	It requires less space
Initial cost	Low	High
Nature	It is semi-continuous in loose state.	It is continuous in nature
Popularity	More popular because of less initial cost	Less popular because of high initial cost
Quality of Bricks	Percentage of good quality bricks is small	Percentage of good quality bricks is more.

Note:- 

 These two kiln's are used to burn the bricks.

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Rubber vs. Concrete vs. Steel Material Properties Comparison

Material Properties Comparison: Rubber vs. Steel vs. Concrete

Material Properties

Property	Rubber	Steel	Concrete
Elasticity	High - Can deform significantly under stress and return to its original shape.	Low - Does not deform much under stress and retains its shape even under significant loads.	Low - Has relatively low elasticity, but can experience some deformation under stress.
Modulus of Elasticity (GPa)	~1 MPa to ~100 MPa - Relatively low modulus of elasticity.	~200 GPa to ~210 GPa - High modulus of elasticity.	~20 GPa to ~40 GPa - Moderate modulus of elasticity.
Strength	Lower strength - Rubber is not as strong as steel and may deform significantly under stress but can recover its original shape when the stress is removed.	High - Steel is a strong material, capable of withstanding heavy loads and high-stress conditions.	Variable - Concrete is relatively strong in compression, making it suitable for load-bearing structures, but weaker in tension.
Density	Low - Less dense than steel, making it lighter and suitable for weight-sensitive applications.	Moderate - Denser than rubber, providing more mass and stability in structural uses.	Moderate - Has a moderate density.
Plasticity	Low - Limited plasticity, does not undergo permanent deformation easily.	Moderate - Can exhibit plastic behavior under certain conditions, allowing shaping without fracturing.	Variable - Can exhibit plasticity during curing, limited compared to metals.
Applications	Used in tires, seals, shock absorbers, and flexible components due to its high elasticity and vibration absorption.	Ideal for structural applications like building construction, bridges, machinery, and load-bearing structures due to its high strength and rigidity.	Widely used in construction for foundations, beams, columns, and walls due to its compressive strength and versatility.

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Comparison between Steel and Rubber Material Properties

Material Properties Comparison: Rubber vs. Steel

Property	Rubber	Steel
Elasticity	High - Rubber can deform significantly under stress and return to its original shape.	Low - Steel does not deform much under stress and retains its shape even under significant loads.
Modulus of Elasticity (GPa)	~1 MPa to ~100 MPa - Rubber has a relatively low modulus of elasticity.	~200 GPa to ~210 GPa - Steel has a high modulus of elasticity.
Strength	Low - Rubber is not as strong as steel and is more susceptible to permanent deformation under high stress.	High - Steel is a strong material, capable of withstanding heavy loads and high-stress conditions.
Density	Low - Rubber is less dense than steel, making it lighter and suitable for weight-sensitive applications.	Moderate - Steel is denser than rubber, providing more mass and stability in structural uses.
Applications	Various applications in tires, seals, shock absorbers, and flexible components due to its high elasticity and vibration absorption.	Ideal for structural applications like building construction, bridges, machinery, and load-bearing structures due to its high strength and rigidity.

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