Artificial Materials (Glass)
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Artificial Materials (Glass):-
What do you understand by glass?
Definition: It is hard, brittle,
transparent material composed of silica, oxides of sodium, potassium, calcium
and other material.
- From long years ago glass is used as construction material in construction industries.
- Due to advance techniques in manufacturing process it used in construction for different purpose.
- The strength of glass is varies from 370 to 690kg/cm2.
What is manufacturing process of glass?
- Melting: In first stage all raw material required for manufacturing are melt in furnaces of kiln.
- Shaping: In this stage required shape to melted glass to be given.
- Annealing: This process of treating the surface of glass to proper shining or smoothness.
- Finishing: This is final process in this final shape is to be given and sharpness of glass removed.
What are the properties of glass?
Thickness:
- The thickness of glass varies from 2mm to 60mm.
- If thickness will increases transparency will decreases.
- Normal glass is 87% to visible light.
Weight:
- Density of glass is 2500kg/m3.
- This is 2.5 times greater than water density.
Thermal conductivity:
- The rate of heat conducting or transferring along the body is called thermal conductivity.
- It is 1.5 to 3.5 g-cal/cm2/sec at 0oC. And at 250oC it will increases 25%.
- Although glass having low thermal conductivity glass is used for cook dishes.
- Glass absorbs most of heat radiations, but metals reflects lot of the heat radiations.
Light and heat translation:
- Glass absorbs, refracts or transmits, and reflects light.
- Transference of glass is depends on presence of free electrons.
- Clear glass is not completely transparent for 6mm thick glass 87% spectrum to visible light.
Chemical durability:
- Glass having good chemical resistance to chemical.
- By using this property all medicines are packed in glass.
Sound Insulation:
- Glass is good sound insulating material. Sound insulation is used to reduce the sound when passes from one side of partition material to is other side.
- Sound absorption coefficient for 6mm plate is –
0.1 for low frequency.
0.04
for medium frequency.
0.02
for high frequency.
What are the applications of glass (uses)?
- In chemical: 1. For chemistry laboratories test tubes, different glasses, etc. 2. In medicines packing.
- Lighting: 1. Different types of lamps. 2. For window for light passing in buildings.
- Electrical: 1. Cathode rays in televisions. 2. X-ray tubes.
- Optical: 1. Eye-glass and goggles, 2. Prisms, 3. Mirror.
- Thermal: 1. Furnace window. 2. Heat absorbing flat glass.
What are different types of glass?
- Silica glass:
- It is simplest type of glass.
- It composed of silica alone.
- It has high softening point.
- It has lower expansion then other type of glass.
- It has higher thermal and chemical resistance than other type of glass.
Uses: It used for ultra optical
window, ultra violate transmitting, laboratory wares.
- Soda-lime-silica glass:
- This is first glass manufactured.
- Now it called as soda-lime-silica, soda-lime or simply lime glass.
- Raw materials required for this is not very costly.
- This is easy to melt and fabricate.
Uses: Generally it is used when
chemical durability and great heat resistance is not necessary. Window glass,
bottles of all kinds, light bulbs, etc.
- Lead glass:
- It is obtained by reducing percentage of CaO completely and increasing percentage of PbO in lime glass.
- It is easier to melt.
- Percentage of PbO increased up to 80%.
- This type of glass cut X-rays and gamma rays. But transparent to visible radiations.
Uses: it used in electric tubes,
TV sets, etc.
- Borosilicate Galss:
- During manufacturing process B2O3 is used.
- Due to adding SiO2 percentage of Na2O decreases considerably.
- Still melting point is not increases.
- Coefficient of expansion increases 25 to 50% than lime glass due to addition of B2O3.
Uses: it is used for industrial
piping, cooking utensils, laboratory wears, high temperature thermometers, etc.
Write short note on glass is used for cladding?
- The process of fixing glass to outside of building to give decoration effect is known as glass cladding.
- Glass cladding is also used for partition purpose for interior decoration purpose.
- The glass used for this purpose should be strong and thick.
- It should have good weather proofing and high thermal insulating properties.
- Glass sheet or panels can be fixed by providing steel or wooden frame on wall and they are fixed in frame by using good quality of glass glue.
- Transparent, coloured glass is used for cladding purpose to increase appearance of building.
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