Monday 18 February 2013

Terracotta



Terracotta is clay-based earthenware made from ceramic. They are fine materials used in building constructions and making sculptures.

In general, they are brownish orange in color, which may vary depending on the constitution. 

But it is essential to understand that, although terracotta is similar to pottery, it’s not made from a potter’s wheel.

The making of a terracotta material involves the following sequence of steps.

Clay material is first refined and then molded into the desirable shape for production.

The clay is allowed to dry for sometime and then burnt on a kiln.

The transition of the color from brown to brownish orange takes place at this stage.

The material is generally porous and can be made water tight by surface burnishing the composition before burning in a kiln.

They find applications in garden ware, building decoration, tableware, and so on.

The efficiency of the final product can be checked by striking which will result in a ringing sound. Terracotta can also be recycled from older items of terracotta.

Terracotta occupies a central position in Indian life and culture. 

Terracotta art bears testimony to the varied and traditional practices of ancient India.

Sunday 10 February 2013

Hookah



Hookah is a stemmed instrument used for smoking flavored Tobacco. Here, the smoke is passed through a water basin before inhalation. There are some essential components in a Hookah which are mentioned below along with their description.

Bowl is a container which stands as the head of the Hookah and it holds the coal and tobacco during the smoking session. A perforated aluminum foil or screen typically glass or metal covers the bowl. 

A Windscreen covers the bowl area, with some form of air holes. This prevents wind from increasing the burn rate and temperature of the coal. It also prevents ash from being blown onto the surrounding environment. 

Hose refers to a slender flexible tube that allows the smoke to be drawn for a distance, cooling down before inhalation. The end is typically fitted with a metal, wooden, or plastic mouthpiece of different shapes, size, color or material type. 

A Purge valve is connected to the airspace in the water jar to purge stale smoke which has been sitting unused in the jar for too long. The cover should be opened and cleaned of residue and corrosion regularly to ensure proper sealing.

Water jar lies at the bottom of the Hookah. Smoke from the bowl passes through the body and it bubbles through the water. This cools and humidifies the smoke. Liquids such as fruit juice may be added to the water or used in substitution for adding a fruit flavour. 
Plate or ashtray sits just below the bowl to catch ashes falling off the Hookah.

Grommets are usually placed between the body and the water jar. They help to seal the joints between the parts, therefore decreasing the amount of air coming in and maximizing the smoke breathed in.

Diffuser is a piece attached to the bottom of the stem, usually made of plastic, to make a smoother smoke and a subdued noise. This also cools the smoke down more efficiently. It is used as a luxury item for a premium smoking experience and is not a required component.

The bottom jar of the hookah is filled with water. Tobacco is placed inside the bowl at the top of the hookah. Often the bowl is covered with perforated tin foil or a metal screen and coal placed on top. Charcoal used for hookah smoking must be hard, high density, easy to ignite, and burn longer with persistent heat.

When one inhales through the hose, air is pulled through the charcoal and into the bowl holding the tobacco. The hot air, heated by the charcoal vaporizes the tobacco, thus producing smoke, which is passed down through the body tube that extends into the water in the jar. It bubbles up through the water, losing heat, and fills the top part of the jar, to which the hose is attached for inhaling. Stale smoke, if any has to be exhausted through the purge valve before inhaling. 

Smoking the hookah has gained popularity outside of its native Indian region, in Iran, Pakistan and the Middle East, and is gaining popularity in North America, South America, Europe, Australia, Southeast Asia, Tanzania and South Africa.



Thursday 7 February 2013

Filigree - A Delicate Metal Art



Filigree is a kind of delicate metalwork, usually comprising of gold and silver, embodied with beads and threads. The elements are soldered over a metal surface, arranged with several artistic motifs. 

A motif is a design or composition in the iconography of a particular subject. The same motif maybe repeated throughout the filigree structure or different designs can be employed. This kind of artwork is popular in Indian and other Asian civilizations. 

Fine threads of metal are united at their points of contact with the ground surface using flux. A blowpipe is generally used to connect the fine threads onto the metal surface. 

At first, Granulated motifs are cut into small pieces so that it can be easily placed onto the metal surface. These cut pieces are then mixed with flux to make it apt for melting purpose. The compound is then placed in the holes provided with pitted charcoal.

After this, melting is carried out with a blowpipe that reaches the charcoal layer first and slowly gets down to the motifs which are placed beneath. 

On melting, the bits of wire which are present in the flux get curled up and take a natural spherical shape. The beauty of this artwork is that, each motif on melting ends up slightly different from one another. 

Small grains or beads are placed in these wire junctions.  A stouter wire is placed as a protective layer, as this metal surface is very delicate.

The final step involves decorating the filigree surface with minute beads and globules of gold or other ornamental materials which are soldered to form patterns on a metal surface. 


Monday 4 February 2013

Sandstone



Sandstone is a form of sedimentary rock comprising silicate minerals and rock fragments that were transported by moving fluids. The major composition of Sandstone involves quartz, feldspar, mica, clay minerals and essentially lithic or rock fragments.

The formation of sandstone takes place under two primary stages. At first, the sedimentation process takes place where the several minerals from different parts of the surface are carried over by river, fluids, lava or so on.

Next, these sedimented minerals compact under high pressure and precipitate to form Sandstone, which is nothing but a composed form of hardened sand.

The environment where the minerals are deposited also plays a major role in determining the characteristics of the resulting sandstone. Essential features of the Sandstone, to quote, grain size, sorting, geometrical shape, composition and so on are based on the surroundings where it originates. 

Some common environments are terrestrial like rivers, lakes, deserts and marine like deltas, beach, turbidites.

The color of the sandstone may vary from region to region depending on the topographical features of the Earth’s crust. But they are generally found in tan, brown, yellow, gray, pink, white and black colors.

Sandstone has huge pores that render to the percolation of large amount of water or other liquid storage within them. This feature attributes to the grained surface and solid shape of the Sandstone.

Sandstone is familiar with the coastal sea areas and especially, the deserts where rock surfaces are fine grained and fractured by the seismic activity of the bottom layer of sedimentary rocks.

Sandstone is mined by quarrying. A very pure form of quartz silicate called Quartzite is also obtained from Sandstone by allowing to heavy pressure and heat along with tectonic compression.

Sandstones are relatively soft which makes it easy to carve. It is primarily used for domestic construction and house wares. It has been widely used around the world in constructing temples, cathedrals, homes, and other buildings. It is also used for artistic purposes to create ornamental fountains and statues.