The Taj Mahal is a white marble mausoleumlocated in Agra, India. It was built

by Mughal emperor Shah Jahan in memory of his third wife, Mumtaz Mahal. The Taj Mahal is widely

recognized as "the jewel of Muslim art in India and one of the universally admired masterpieces of the

world's heritage.It coveres area about 221 hectare (552 Acres) which include 38 hectare taj mahal

and 183 hectare taj protected forest are."[3]

Taj Mahal is the finest example of Mughal architecture, a style that combines elements

from Persian, Turkish and Indian architectural styles.[4][5]

In 1983, the Taj Mahal became a UNESCO World Heritage Site. While the

white domed marble mausoleum is the most familiar component of the Taj Mahal, it is actually an

integrated complex of structures. The construction began around 1632 and was completed around

1653, employing thousands of artisans and craftsmen.[6]

The construction of the Taj Mahal was

entrusted to a board of architects under imperial supervision, including Abd ul-Karim Ma'mur Khan,

Makramat Khan, and Ustad Ahmad Lahauri.[7][8]

Lahauri[9]

is generally considered to be the principal

designer.[10]

Origin and inspiration

In 1631, Shah Jahan, emperor during the Mughal empire's period of greatest prosperity, was grief-

stricken when his third wife, Mumtaz Mahal, died during the birth of their 14th child,Gauhara

Begum.[11]

Construction of the Taj Mahal began in 1632.[12]

The court chronicles of Shah Jahan's grief

illustrate the love story traditionally held as an inspiration for Taj Mahal.[13][14]

The principal mausoleum

was completed in 1648 and the surrounding buildings and garden were finished five years later.

Emperor Shah Jahan himself described the Taj in these words:[15]

Shah Jahan, who commissioned

the Taj Mahal -"Shah jahan on a

globe" from the Smithsonian

Institution

Artistic depiction of Mumtaz

Mahal

1. The Moonlight Garden to the north of the Yamuna.

2. Terrace area: Tomb, Mosque and Jawab.

3. Charbagh (gardens).

4. Gateway, attendant accommodations, and other tombs.

5. Taj Ganji (bazaar)

Should guilty seek asylum here,

Like one pardoned, he becomes free from sin.

Should a sinner make his way to this mansion,

All his past sins are to be washed away.

The sight of this mansion creates sorrowing sighs;

And the sun and the moon shed tears from their eyes.

In this world this edifice has been made;

To display thereby the creator's glory.

The Taj Mahal incorporates and expands on design traditions of Persian architecture and earlier

Mughal architecture. Specific inspiration came from successful Timurid and Mughal buildings

including; the Gur-e Amir (the tomb of Timur, progenitor of the Mughal dynasty,

in Samarkand),[16]

Humayun's Tomb, Itmad-Ud-Daulah's Tomb (sometimes called the Baby Taj), and

Shah Jahan's own Jama Masjid in Delhi. While earlier Mughal buildings were primarily constructed of

red sandstone, Shah Jahan promoted the use of white marble inlaid with semi-precious stones, and

buildings under his patronage reached new levels of refinement.[17]

Architecture

The tomb

The tomb is the central focus of the entire complex of the Taj Mahal. This large, white marble

structure stands on a square plinth and consists of a symmetrical building with aniwan (an arch-

shaped doorway) topped by a large dome and finial. Like most Mughal tombs, the basic elements are

Persian in origin.

The Taj Mahal seen from the banks of river Yamuna

The base structure is essentially a large, multi-chambered cube with chamfered corners, forming an

unequal octagon that is approximately 55 metres (180 ft) on each of the four long sides. On each of

these sides, a huge pishtaq, or vaulted archway, frames the iwan with two similarly shaped, arched

balconies stacked on either side. This motif of stacked pishtaqs is replicated on the chamfered corner

areas, making the design completely symmetrical on all sides of the building. Four minarets frame the

tomb, one at each corner of the plinth facing the chamfered corners. The main chamber houses the

false sarcophagi of Mumtaz Mahal and Shah Jahan; the actual graves are at a lower level.

Viewed from the east

The marble dome that surmounts the tomb is the most spectacular feature. Its height of around 35

metres (115 ft) is about the same as the length of the base, and is accentuated as it sits on a

cylindrical "drum" which is roughly 7 metres (23 ft) high. Because of its shape, the dome is often

called an onion dome or amrud (guava dome). The top is decorated with a lotus design, which also

serves to accentuate its height. The shape of the dome is emphasised by four smaller

domed chattris (kiosks) placed at its corners, which replicate the onion shape of the main dome. Their

columned bases open through the roof of the tomb and provide light to the interior. Tall decorative

spires (guldastas) extend from edges of base walls, and provide visual emphasis to the height of the

dome. The lotus motif is repeated on both the chattris and guldastas. The dome and chattris are

topped by a gilded finial, which mixes traditional Persian and Hindustani decorative elements.

Viewed from Masjid

Reflection of Taj

The main finial was originally made of gold but was replaced by a copy made of gilded bronze in the

early 19th century. This feature provides a clear example of integration of traditional Persian and

Hindu decorative elements. The finial is topped by a moon, a typical Islamic motif whose horns

point heavenward. Because of its placement on the main spire, the horns of the moon and the finial

point combine to create a trident shape, reminiscent of traditional Hindu symbols of Shiva.[6]

The minarets, which are each more than 40 metres (130 ft) tall, display the designer's penchant for

symmetry. They were designed as working minarets — a traditional element of mosques, used by

the muezzin to call the Islamic faithful to prayer. Each minaret is effectively divided into three equal

parts by two working balconies that ring the tower. At the top of the tower is a final balcony

surmounted by a chattri that mirrors the design of those on the tomb. The chattris all share the same

decorative elements of a lotus design topped by a gilded finial. The minarets were constructed slightly

outside of the plinth so that, in the event of collapse, (a typical occurrence with many tall constructions

of the period) the material from the towers would tend to fall away from the tomb.

Base, dome, and minaret

Finial

Main iwan and side pishtaqs

Simplified diagram of the Taj Mahal floor plan

Minaret

The calligraphy on the Great Gate reads "O Soul, thou art at rest. Return to the Lord at peace with

Him, and He at peace with you."[19]

The calligraphy was created by a calligrapher named Abd ul-Haq, in 1609. Shah Jahan conferred the

title of "Amanat Khan" upon him as a reward for his "dazzling virtuosity".[8]

Near the lines from the

Qur'an at the base of the interior dome is the inscription, "Written by the insignificant being, Amanat

Khan Shirazi."[20]

Much of the calligraphy is composed of florid thuluth script, made of jasper or black

marble,[8]

inlaid in white marble panels. Higher panels are written in slightly larger script to reduce the

skewing effect when viewed from below. The calligraphy found on the marble cenotaphs in the tomb

is particularly detailed and delicate.

Abstract forms are used throughout, especially in the plinth, minarets, gateway, mosque, jawab and,

to a lesser extent, on the surfaces of the tomb. The domes and vaults of the sandstone buildings are

worked with tracery of incised painting to create elaborate geometric forms. Herringbone inlays define

the space between many of the adjoining elements. White inlays are used in sandstone buildings, and

dark or black inlays on the white marbles. Mortared areas of the marble buildings have been stained

or painted in a contrasting colour, creating geometric patterns of considerable complexity. Floors and

walkways use contrasting tiles or blocks in tessellation patterns.

On the lower walls of the tomb there are white marble dados that have been sculpted with

realistic bas relief depictions of flowers and vines. The marble has been polished to emphasise the

exquisite detailing of the carvings and the dado frames and archway spandrels have been decorated

with pietra dura inlays of highly stylised, almost geometric vines, flowers and fruits. The inlay stones

are of yellow marble, jasper and jade, polished and levelled to the surface of the walls.

Herringbone

Plant motifs

Spandrel detail

Incised painting

Reflective tiles normal exposure

Calligraphy of Persianpoems

Finial Floor Tiling

The complex is set around a large 300-metre (980 ft) square charbagh or Mughal garden. The garden

uses raised pathways that divide each of the four quarters of the garden into 16 sunkenparterres or

flowerbeds. A raised marble water tank at the center of the garden, halfway between the tomb and

gateway with a reflecting pool on a north-south axis, reflects the image of the mausoleum. The raised

marble water tank is called al Hawd al-Kawthar, in reference to the "Tank of Abundance" promised

to Muhammad.[21]

Elsewhere, the garden is laid out with avenues of trees and fountains.[22]

The

charbagh garden, a design inspired by Persian gardens, was introduced to India by the first Mughal

emperor, Babur. It symbolises the four flowing rivers of Jannah(Paradise) and reflects the Paradise

garden derived from the Persian paridaeza, meaning 'walled garden'. In mystic Islamic texts of

Mughal period, Paradise is described as an ideal garden of abundance with four rivers flowing from a

central spring or mountain, separating the garden into north, west, south and east.

Most Mughal charbaghs are rectangular with a tomb or pavilion in the center. The Taj Mahal garden is

unusual in that the main element, the tomb, is located at the end of the garden. With the discovery

of Mahtab Bagh or "Moonlight Garden" on the other side of the Yamuna, the interpretation of

the Archaeological Survey of India is that the Yamuna river itself was incorporated into the garden's

design and was meant to be seen as one of the rivers of Paradise.[23]

The similarity in layout of the

garden and its architectural features with the Shalimar Gardens suggest that they may have been

designed by the same architect, Ali Mardan.[24]

Early accounts of the garden describe its profusion of

vegetation, including abundant roses, daffodils, and fruit trees.[25]

As the Mughal Empire declined, the

tending of the garden also declined, and when the British took over the management of Taj Mahal

during the time of the British Empire, they changed the landscaping to resemble that of lawns of

London.[26]

Outlying buildings

The Great gate (Darwaza-i rauza)—gateway to the Taj Mahal

The Taj Mahal complex is bounded on three sides by crenellated red sandstone walls, with the river-

facing side left open. Outside the walls are several additional mausoleums, including those of Shah

Jahan's other wives, and a larger tomb for Mumtaz's favourite servant. These structures, composed

primarily of red sandstone, are typical of the smaller Mughal tombs of the era. The garden-facing

inner sides of the wall are fronted by columned arcades, a feature typical of Hindu temples which was

later incorporated into Mughal mosques. The wall is interspersed with domedchattris, and small

buildings that may have been viewing areas or watch towers like the Music House, which is now used

as a museum.

Interior of the Taj Mahal mosque

The main gateway (darwaza) is a monumental structure built primarily of marble which is reminiscent

of Mughal architecture of earlier emperors. Its archways mirror the shape of tomb's archways, and

its pishtaq arches incorporate the calligraphy that decorates the tomb. It utilises bas-relief and pietra

dura inlaid decorations with floral motifs. The vaulted ceilings and walls have elaborate geometric

designs, like those found in the other sandstone buildings of the complex.

Taj Mahal mosque or masjid

At the far end of the complex, there are two grand red sandstone buildings that are open to the sides

of the tomb. Their backs parallel the western and eastern walls, and the two buildings are precise

mirror images of each other. The western building is a mosque and the other is the jawab (answer),

whose primary purpose was architectural balance, although it may have been used as a guesthouse.

The distinctions between these two buildings include the lack of mihrab(a niche in a mosque's wall

facing Mecca) in the jawab and that the floors of jawab have a geometric design, while the mosque

floor was laid with outlines of 569 prayer rugs in black marble. The mosque's basic design of a long

hall surmounted by three domes is similar to others built by Shah Jahan, particularly to his Masjid-

Jahan Numa, or Jama Masjid, Delhi. The Mughal mosques of this period divide the sanctuary hall into

three areas, with a main sanctuary and slightly smaller sanctuaries on either side. At the Taj Mahal,

each sanctuary opens onto an enormous vaulting dome. These outlying buildings were completed in

1643.

Construction

Ground layout of the Taj Mahal

The Taj Mahal was built on a parcel of land to the south of the walled city of Agra. Shah Jahan

presented Maharajah Jai Singh with a large palace in the center of Agra in exchange for the

land.[27]

An area of roughly three acres was excavated, filled with dirt to reduce seepage, and levelled

at 50 metres (160 ft) above riverbank. In the tomb area, wells were dug and filled with stone and

rubble to form the footings of the tomb. Instead of lashed bamboo, workmen constructed a colossal

brick scaffold that mirrored the tomb. The scaffold was so enormous that foremen estimated it would

take years to dismantle. According to the legend, Shah Jahan decreed that anyone could keep the

bricks taken from the scaffold, and thus it was dismantled by peasants overnight. A fifteen kilometre

(9.3 mi) tamped-earth ramp was built to transport marble and materials to the construction site and

teams of twenty or thirty oxen pulled the blocks on specially constructed wagons. An elaborate post-

and-beam pulley system was used to raise the blocks into desired position. Water was drawn from the

river by a series of purs, an animal-powered rope and bucket mechanism, into a large storage tank

and raised to a large distribution tank. It was passed into three subsidiary tanks, from which it was

piped to the complex.

The plinth and tomb took roughly 12 years to complete. The remaining parts of the complex took an

additional 10 years and were completed in order of minarets, mosque and jawab, and gateway. Since

the complex was built in stages, discrepancies exist in completion dates due to differing opinions on

"completion". For example, the mausoleum itself was essentially complete by 1643, but work

continued on the rest of the complex. Estimates of the cost of construction vary due to difficulties in

estimating costs across time. The total cost has been estimated to be about 32 million Rupees at that

time.[28]

The Taj Mahal was constructed using materials from all over India and Asia and over 1,000 elephants

were used to transport building materials. The translucent white marble was brought from Makrana,

Rajasthan, the jasper from Punjab, jade and crystal from China. The turquoise was from Tibet and

the Lapis lazuli from Afghanistan, while the sapphire came from Sri Lanka and

the carnelian fromArabia. In all, twenty eight types of precious and semi-precious stones were inlaid

into the white marble.

The construction of the Taj Mahal was entrusted to a board of architects under imperial supervision,

including Abd ul-Karim Ma'mur Khan, Makramat Khan, and Ustad Ahmad Lahauri.[7][8]

Lahauri[9]

is

generally considered to be the principal designer.[10]

Artist's impression of the Taj Mahal, from the Smithsonian Institution

A labour force of twenty thousand workers was recruited across northern India. Sculptors

from Bukhara, calligraphers from Syria and Persia, inlayers from southern India, stonecutters

from Baluchistan, a specialist in building turrets, another who carved only marble flowers were part of

the thirty-seven men who formed the creative unit. Some of the builders involved in construction of Taj

Mahal are:

Ismail Afandi (a.k.a. Ismail Khan) of the Ottoman Empire — Turkish architect, designer of the

main dome.[29]

Ustad Isa (Isa Muhammad Effendi) of Persia — Turkish architect, trained by Koca Mimar Sinan

Agha of the Ottoman Empire and frequently credited with a key role in the architectural

design.[30][31]

'Puru' from Benarus, Persia — has been mentioned as a supervising architect.[32]

Qazim Khan, a native of Lahore – cast the solid gold finial.

Chiranjilal, a lapidary from Delhi — the chief sculptor and mosaicist.

Amanat Khan from Shiraz, Iran — the chief calligrapher.[33]

Muhammad Hanif — a supervisor of masons.

Mir Abdul Karim and Mukkarimat Khan of Shiraz — handled finances and management of daily

production.

History

Taj Mahal by Samuel Bourne, 1860.

Soon after the Taj Mahal's completion, Shah Jahan was deposed by his son Aurangzeb and put

under house arrest at nearby Agra Fort. Upon Shah Jahan's death, Aurangzeb buried him in the

mausoleum next to his wife.[34]

By the late 19th century, parts of the buildings had fallen badly into disrepair. During the time of

the Indian rebellion of 1857, the Taj Mahal was defaced by British soldiers and government officials,

who chiselled out precious stones and lapis lazuli from its walls. At the end of the 19th century,

British viceroy Lord Curzon ordered a sweeping restoration project, which was completed in

1908.[35][36]

He also commissioned the large lamp in the interior chamber, modelled after one in

a Cairo mosque. During this time the garden was remodelled with British-style lawns that are still in

place today.[26]

Agra Fort, is a monument, is a UNESCO World Heritage site located in Agra, Uttar Pradesh, India. It

is about 2.5 km northwest of its more famous sister monument, the Taj Mahal. The fort can be more

accurately described as a walled city. After Panipat, Mughals captured the fort and a vast treasure -

which included a diamond that was later named as the Koh-i-Noor diamond - was

seized. Babur stayed in the fort in the palace of Ibrahim. He built a baoli (step well) in

it. Humayun was crowned here in 1530. Humayunwas defeated in Bilgram in 1540. Sher Shah held

the fort for five years. The Mughals defeated the Hindu King Hemu finally at the Second Battle of

Panipat in 1556.

History

Akbar supervises the building of the Fort at Agra

The passing of Shah Jahan inside theAgra Fort beside his daughter and caretaker Princess Jahanara.

It was originally a brick fort, held by the Hindu Sikarwar Rajputs. It was mentioned for the first time in

1080 AD when a Ghaznavide force captured it. Sikandar Lodi (1488–1517) was the first Sultan of

Delhi who shifted to Agra and lived in the fort. He governed the country from here and Agra assumed

the importance of the second capital. He died in the fort in 1517 and his son, Ibrahim Lodi, held it for

nine years until he was defeated and killed at Panipat in 1526. Several palaces, wells and a mosque

were built by him in the fort during his period.

After Panipat, Mughals captured the fort and a vast treasure - which included a diamond that was

later named as the Koh-i-Noor diamond - was seized. Babur stayed in the fort in the palace of

Ibrahim. He built a baoli (step well) in it. Humayun was crowned here in 1530. Humayun was defeated

in Bilgram in 1540. Mughals under Akbar, defeated the Hindu King Hemu finally at the Second Battle

of Panipat in 1556.

Realizing the importance of its central situation, Akbar made it his capital and arrived in Agra in 1558.

His historian, Abdul Fazal, recorded that this was a brick fort known as 'Badalgarh' . It was in a ruined

condition and Akbar had it rebuilt with red sandstone from Barauli area inRajasthan. Architects laid

the foundation and it was built with bricks in the inner core with sandstone on external surfaces. Some

1,444,000 builders worked on it for eight years, completing it in 1573.

It was only during the reign of Akbar's grandson, Shah Jahan, that the site took on its current state.

The legend is that Shah Jahan built the beautiful Taj Mahal for his wife, Mumtaz Mahal. Unlike his

grandfather, Shah Jahan tended to have buildings made from white marble, often inlaid with gold or

semi-precious gems. He destroyed some of the earlier buildings inside the fort in order to make his

own.

At the end of his life, Shah Jahan was deposed and restrained by his son, Aurangzeb, in the fort. It is

rumored that Shah Jahan died in Muasamman Burj, a tower with a marble balcony with a view of the

Taj Mahal.

The fort was the site of a battle during the Indian rebellion of 1857, which caused the end of

the British East India Company's rule in India, and led to a century of direct rule of India by Britain.

Layout

Inside the Musamman Burj, where Shah Jahan spent the last seven years of his life under house arrest by his

son Aurangzeb.

Map of the fort

The 94-acre (380,000 m2) fort has a semicircular plan, its chord lies parallel to the river and its walls

are seventy feet high. Double ramparts have massive circular bastions at intervals,

withbattlements, embrasures, machicolations and string courses. Four gates were provided on its four

sides, one Khizri gate opening on to the river.

Two of the fort's gates are notable: the "Delhi Gate" and the "Lahore Gate." The Lahore Gate is also

popularly also known as the Amar Singh Gate, for Amar Singh Rathore.

Decorated column

The monumental Delhi Gate, which faces the city on the western side of the fort, is considered the

grandest of the four gates and a masterpiece of Akbar's time. It was built circa 1568 both to enhance

security and as the king's formal gate, and includes features related to both. It is embellished with

inlay work in white marble, proof to the richness and power of the Great Mughals. Awooden

drawbridge was used to cross the moat and reach the gate from the mainland; inside, an inner

gateway called Hathi Pol ("Elephant Gate") - guarded by two life-sized stone elephantswith their riders

- added another layer of security. The drawbridge, slight ascent, and 90-degree turn between the

outer and inner gates make the entrance impregnable. During a siege, attackers would employ

elephants to crush a fort's gates. Without a level, straight run-up to gather speed, however, something

prevented by this layout, elephants are ineffective.

Because the Indian military (the Parachute Brigade in particular) is still using the northern portion of

the Agra Fort, the Delhi Gate cannot be used by the public. Tourists enter via the Amar Singh Gate.

The site is very important in terms of architectural history. Abul Fazal recorded that five hundred

buildings in the beautiful designs of Bengal and Gujarat were built in the fort. Some of them were

demolished by Shahjahan to make way for his white marble palaces. Most of the others were

destroyed by the British between 1803 and 1862 for raising barracks. Hardly thirty Mughal buildings

have survived on the south-eastern side, facing the river. Of these, the Delhi Gate and Akbar

Gate and one palace - "Bengali Mahal" - are representative Akbari buildings.

Akbar Darwazza (Akbar Gate) was renamed Amar Singh Gate by the British. The gate is similar in

design to the Delhi Gate. Both are built of red sandstone.

The Bengali Mahal is built of red sandstone and is now split into Akbari Mahal and Jahangiri mahal.

Some of the most historically interesting mixing of Hindu and Islamic architecture are found here. In

fact, some of the Islamic decorations feature haraam (forbidden) images of living creatures -

dragons, elephants and birds, instead of the usual patterns and calligraphy seen in Islamic surface

decoration.

Charminar , built in 1591 AD, is a landmark monument located in Hyderabad, Andhra Pradesh, India.

The English name is a transliteration and combination of the Urdu words Chār and Minar, translating

to "Four Towers"; the eponymous towers are ornate minarets attached and supported by four grand

arches.[1][2]

The landmark has become a global icon of Hyderabad, listed among the most recognized

structures of India.[3]

The Charminar is on the east bank of Musi river.[4]

To the northeast lies the Laad

Bazaar and in the west end lies the granite-made richly ornamented Makkah Masjid.[1][2]

History

Sultan Muhammad Quli Qutb Shah, the fifth ruler of the Qutb Shahi dynasty built Charminar in 1591

AD,[5]

shortly after he had shifted his capital from Golkonda to what is now known as Hyderabad.[6]

He

built this famous structure to commemorate the elimination of a plague epidemic from this city. He is

said to have prayed for the end of a plague that was ravaging his city and vowed to build

a masjid (Islamic mosque) at the very place where he was praying. In 1591 while laying the

foundation of Charminar, Quli Qutb Shah prayed: "Oh Allah, bestow unto this city peace and

prosperity. Let millions of men of all castes, creeds and religions make it their abode, like fish in the

water.[citation needed]

"

The mosque became popularly known as Charminar because of the two Urdu words char, meaning

four, and minar, meaning tower, combined to form Charminar.[7]

It is said that, during the Mughal Governorship between Qutb Shahi and Asaf Jahi rule, the south

western minaret "fell to pieces" after being struck by lightning and "was forthwith repaired" at a cost of

Rs 60,000.[2] In 1824, the monument was replastered at a cost of Rs 100,000.

In its heyday, the Charminar market had some 14,000 shops. Today the famous markets known as

Laad Baazar and Pather Gatti, near the Charminar, are a favour, of tourists and locals alike for

jewellery, especially known for exquisite bangles and pearls respectively.

In 2007, Hyderabadi Muslims living in Pakistan constructed a small-scaled quasi replica of the

Charminar at the main crossing of the Bahadurabad neighborhood in Karachi.[8]

Structure

The structure is made of granite, limestone, mortar and pulverised marble. Initially the monument with

its four arches was so proportionately planned that when the fort was opened one could catch a

glimpse of the bustling Hyderabad city as these Charminar arches were facing the most active royal

ancestral streets. There is also a legend of an underground tunnel connecting theGolkonda to

Charminar, possibly intended as an escape route for the Qutb Shahi rulers in case of a siege, though

the location of the tunnel is unknown.[9]

The Charminar is a square edifice with each side 20 meters (approximately 66 feet) long, with four

grand arches each facing a cardinal point that open into four streets. At each corner stands an

exquisitely shaped minaret, 56 meters (approximately 184 feet) high with a double balcony. Each

minaret is crowned by a bulbous dome with dainty petal like designs at the base.

A beautiful mosque is located at the western end of the open roof and the remaining part of the roof

served as a court during the Qutb Shahi times.

There are 149 winding steps to reach the upper floor. Once atop, the solitude and serenity of the

beautiful interior is refreshing. The space in the upper floor between the minarets was meant for

Friday prayers. There are forty-five prayer spaces.[1]

Charminar has the signature style of Islamic architecture.[10]

This great tribute to aesthetics looks

sturdy and solid from a distance and, as one moves closer, it emerges as an elegant and romantic

edifice proclaiming its architectural eminence in all its detail and dignity. Charminar looks equally

spectacular at night when it is illuminated. Apart from being the core of the city’s cultural milieu, it has

become a brand name.

Charminar is a beautiful and impressive square monument. Each of the corners has a tall, pointed

minaret. These four gracefully carved minarets soar to 48.7 m above the ground, commanding the

landscape for miles around. Each minaret has four stories, marked by a delicately carved ring. Unlike

the Taj Mahal, Charminar's four fluted minarets are built into the main structure. The top floor, the

highest point one can reach, provides a panoramic view of the city.[11]

The actual mosque occupies the top floor of the four-storey structure. Madame Blavatsky reports that

each of the floors was meant for a separate branch of learning before the structure was transformed

by the Imperial British administration into a warehouse for opium and liqueurs.[12]

A vault that appears from inside like a dome, supports two galleries within the Charminar, one over

another, and above those a terrace that serves as a roof, bordered with a stone balcony. The main

gallery has 45 covered prayer spaces with a large open space in front to accommodate more people

for Friday prayers.

The monument overlooks another beautiful and grand mosque called Makkah Masjid.[13]

The area

surrounding Charminar is known by same name. A thriving market still lies around the Charminar,

attracting people and merchandise of every description.

The iron pillar (also known as the Ashokan pillar) of Delhi, India, is a 7 m (23 ft) high pillar in

the Qutb complex, notable for the composition of the metals used in its construction.

The pillar, which weighs more than six tons, is said to have been fashioned at the time

of Chandragupta Vikramaditya (375–413) of the Gupta Empire,[1]

though other authorities give dates

as early as 912 BCE.[2]

The pillar initially stood in the center of a Jain temple complex housing twenty-

seven temples that were destroyed by Qutb-ud-din Aybak, and their material was used in building

theQuwwat-ul-Islam mosque and the Qutub Minar complex where the pillar stands today.[3]

The pillar has attracted the attention of archaeologists and metallurgists and has been called "a

testament to the skill of ancient Indian blacksmiths" because of its high resistance to corrosion,[4]

due

to both the Delhi environment providing alternate wetting and drying conditions, and iron with

high phosphorus content conferring protection by the formation of an even layer of crystalline iron

hydrogen phosphate.[5]

The name of the city of Delhi is thought to be based on a legend associated with the pillar

(see History of Delhi).

Description

Detail showing the inscription

The Iron pillar stands within the courtyard of Quwwat-ul-Islam Mosque

Text and translation of the inscription in English at the site

The height of the pillar, from the top of its capital to the bottom of its base, is 23 ft 8 in (7.21 m),

3 ft 8 in (1.12 m) of which is below ground. Its bell pattern capital is 3 ft 6 in (1.07 m) in height, and its

bulb-shaped base is 2 ft 4 in (0.71 m) high. The base rests on a grid of iron bars soldered with lead

into the upper layer of the dressed stone pavement. The pillar's lower diameter is 16.4 in (420 mm),

and its upper diameter 12.05 in (306 mm). It is estimated to weigh more than six tons.[6]

The pillar was erected by Chandragupta Vikramaditya (375 CE–414 CE), (interpretation based on

analysis of archer-type Gupta gold coins) of the Gupta dynastythat ruled northern India 320–

540.[7]

The pillar, with the statue of Chakra at the top, was originally located at a place

called Vishnupadagiri (meaning "hill with footprint of Lord Vishnu").[8]

This has been identified as

modern Udayagiri, situated in the vicinity of Vidisha, Madhya Pradesh. There are several aspects to

the original site of the pillar at Udayagiri. Vishnupadagiri is located on the Tropic of Cancer and,

therefore, was a centre of astronomical studies during the Gupta period. The iron pillar served as

a sundial when it was originally at Vishnupadagiri. The early-morning shadow of the iron pillar fell in

the direction of the foot ofAnantasayin Vishnu (in one of the panels at Udayagiri) only around

the summer solstice (June 21). The Udayagiri site in general, and the iron pillar location in particular,

are evidence for the astronomical knowledge that existed in Gupta India.

The pillar bears a Sanskrit inscription in Brahmi script,[9]

which states that it was erected as a standard

in honour of Lord Vishnu. It also praises the valor and qualities of a king referred to simply as

Chandra, who has been identified with the Gupta King Chandragupta Vikramaditya (375-413). The

inscription reads (in the translation given in the tablets erected by Pandit Banke Rai in 1903):

He, on whose arm fame was inscribed by the sword, when, in battle in the Vanga countries (Bengal),

he kneaded (and turned) back with (his) breast the enemies who, uniting together, came against

(him);-he, by whom, having crossed in warfare the seven mouths of the (river) Sindhu,

the Vahlikas were conquered;-he, by the breezes of whose prowess the southern ocean is even still

perfumed;-

(Line 3.)-He, the remnant of the great zeal of whose energy, which utterly destroyed (his) enemies,

like (the remnant of the great glowing heat) of a burned-out fire in a great forest, even now leaves not

the earth; though he, the king, as if wearied, has quit this earth, and has gone to the other world,

moving in (bodily) from to the land (of paradise) won by (the merit of his) actions, (but) remaining on

(this) earth by (the memory of his) fame;-

(L. 5.)-By him, the king,-who attained sole supreme sovereignty in the world, acquired by his own arm

and (enjoyed) for a very long time; (and) who, having the name of Chandra, carried a beauty of

countenance like (the beauty of) the full-moon,-having in faith fixed his mind upon (the god) Vishnu,

this lofty standard of the divine Vishnu was set up on the hill (called) Vishnupada.

It is believed by some that the pillar was installed in its current location by Vigraha Raja, the

ruling Tomar king.[10]

One of the inscriptions on the iron pillar from A.D. 1052

mentions Tomara king Anangpal II.[11]

A fence was erected around the pillar in 1997 in response to damage caused by visitors. There is a

popular tradition that it was considered good luck if one could stand with one's back to the pillar and

make one's hands meet behind it.

Scientific analysis

The pillar was manufactured by forge welding and is composed of 98% pure wrought iron, is 7.21 m

(23 feet 8 inches) high, with 93 cm (36.6 inches) buried below the present floor level,[12]

and has a

diameter of 41 cm (16 inches) at the bottom, which tapers towards the upper end.

Details of the top of iron pillar, Qutub Minar, Delhi.

In a report published in the journal Current Science, R. Balasubramaniam of the IIT Kanpur explains

how the pillar's resistance to corrosion is due to a passive protective film at the iron-rust interface. The

presence of second-phase particles (slag and unreduced iron oxides) in the microstructure of the iron,

that of high amounts of phosphorus in the metal, and the alternate wetting and drying existing under

atmospheric conditions are the three main factors in the three-stage formation of that protective

passive film.[13]

Lepidocrocite and goethite are the first amorphous iron oxyhydroxides that appear upon oxidation of

iron. High corrosion rates are initially observed. Then, an essential chemical reaction intervenes: slag

and unreduced iron oxides (second phase particles) in the iron microstructure alter the polarization

characteristics and enrich the metal–scale interface with phosphorus, thus indirectly promoting

passivation of the iron[14]

(cessation of rusting activity). The second-phase particles act as a cathode,

and the metal itself serves as anode, for a mini-galvanic corrosion reaction during environment

exposure. Part of the initial iron oxyhydroxides is also transformed into magnetite, which somewhat

slows down the process of corrosion. The ongoing reduction of lepidocrocite and the diffusion of

oxygen and complementary corrosion through the cracks and pores in the rust still contribute to the

corrosion mechanism from atmospheric conditions.

The Iron Pillar in Qutub Minar, c. 1905

The next main agent to intervene in protection from oxidation is phosphorus, enhanced at the metal–

scale interface by the same chemical interaction previously described between the slags and the

metal. The ancient Indian smiths did not add lime to their furnaces. The use of limestone as in

modernblast furnaces yields pig iron that is later converted into steel; in the process, most

phosphorus is carried away by the slag.[15]

The absence of lime in the slag and the deliberate use of

specific quantities of wood with high phosphorus content (for example, Cassia auriculata) during the

smelting induces a higher phosphorus content (> 0.1%, average 0.25%) than in modern iron produced

in blast furnaces (usually less than 0.05%). One analysis gives 0.10% in the slags for 0.18% in the

iron itself. This high phosphorus content and particular repartition are essential catalysts in the

formation of a passive protective film of misawite (d-FeOOH), an amorphous iron oxyhydroxide that

forms a barrier by adhering next to the interface between metal and rust. Misawite, the initial

corrosion-resistance agent, was thus named because of the pioneering studies of Misawa and co-

workers on the effects of phosphorus and copper and those of alternating atmospheric conditions in

rust formation.[16]

The most critical corrosion-resistance agent is iron hydrogen phosphate hydrate (FePO4-H3PO4-

4H2O) under its crystalline form and building up as a thin layer next to the interface between metal

and rust. Rust initially contains iron oxide/oxyhydroxides in their amorphous forms. Due to the initial

corrosion of metal, there is more phosphorus at the metal–scale interface than in the bulk of the

metal. Alternate environmental wetting and drying cycles provide the moisture for phosphoric-acid

formation. Over time, the amorphous phosphate is precipitated into its crystalline form (the latter being

therefore an indicator of old age, as this precipitation is a rather slow happening). The crystalline

phosphate eventually forms a continuous layer next to the metal, which results in an excellent

corrosion resistance layer.[5]

In 1,600 years, the film has grown just one-twentieth of a millimetre

thick.[14]

Balasubramaniam states that the pillar is "a living testimony to the skill of metallurgists of ancient

India". An interview with Balasubramaniam and his work can be seen in the 2005 article by

Veazy.[17]

Further research published in 2009 showed that corrosion has developed evenly over the

surface of the pillar.[18]

It was claimed in the 1920s that iron manufactured in Mirjati near Jamshedpur is similar to the iron of

the Delhi pillar.[19]

Further work on Adivasi (tribal) iron by the National Metallurgical Laboratory in the

1960s did not verify this claim.[20

Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk

is composed mainly of fibroin and produced by certain insect larvae to form cocoons.[1]

The best-

known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx

mori reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-

like structure of the silk fiber, which allows silk cloth to refract incoming light at different angles, thus

producing different colors.

Silks are produced by several other insects, but generally only the silk of moth caterpillars has been

used for textile manufacturing. There has been some research into other silks, which differ at the

molecular level.[2]

Many silks are mainly produced by the larvae of insects undergoing complete

metamorphosis, but some adult insects such as webspinners produce silk, and some insects such

as raspy crickets produce silk throughout their lives.[3]

Silk production also occurs

in Hymenoptera (bees, wasps,

and ants), silverfish, mayflies, thrips, leafhoppers, beetles,lacewings, fleas, flies and midges.[2]

Other

types of arthropod produce silk, most notably various arachnids such as spiders (see spider silk).

Etymology

The word silk comes from Middle English, from Old English sioloc, probably of Slavic origin (akin

to Old Church Slavonic elk), ultimately from Greek srikon, neuter of srikos, silken.[4]

A variety of wild silks, produced by caterpillars other than the mulberry silkworm, have been known

and used in China, South Asia, and Europe since ancient times. However, the scale of production

was always far smaller than that of cultivated silks. There are several reasons for this: firstly, they

differ from the domesticated varieties in color and texture and are therefore less uniform; secondly,

cocoons gathered in the wild have usually had the pupa emerge from them before being discovered

so the silk thread that makes up the cocoon has been torn into shorter lengths; and thirdly, many wild

cocoons are covered in a mineral layer that stymies attempts to reel from them long strands of

silk.[5]

Thus previously the only way to obtain silk suitable for spinning into textiles in areas where

commercial silks are not cultivated is by tedious and labor intensive carding.

Commercial silks originate from reared silkworm pupae which are bred to produce a white colored silk

thread with no mineral on the surface. The pupae are killed by either dipping them in boiling water

before the adult moths emerge or by piercing them with a needle. These factors all contribute to the

ability of the whole cocoon to be unravelled as one continuous thread, permitting a much stronger

cloth to be woven from the silk. Wild silks also tend to be more difficult to dye than silk from the

cultivated silkworm.[6][7]

A technique known as demineralizing allows the mineral layer around the

cocoon to be removed,[8]

leaving only variability in color as a barrier from creating a commercial silk

industry based on wild silks in parts of the world where wild silkmoths thrive, such as Africa and South

America.

Wool is the textile fibre obtained from sheep and certain other animals,including cashmere

from goats, mohair from goats, qiviut from muskoxen, vicuña, alpaca, camel from animals in

the camel family, and angora from rabbits.[1]

Wool has several qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it

grows in staples (clusters).[2]

In the U.S. the term wool is usually restricted to describing the

fibrous protein derived from the specialized skin cells called follicles in sheep, although in

the U.K. it may be used of any long curling fibre such as wood wool, wire wool etc.[3]

Characteristics

Champion hogget fleece, Walcha Show

Fleece of fine New Zealand Merino wool and combed wool top on a wool table

Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibres

attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater

bulk than other textiles, and retain air, which causes the product to retain heat. Insulation also

works both ways; Bedouins and Tuaregs use wool clothes to keep heat out.

The amount of crimp corresponds to the fineness of the wool fibres. A fine wool like Merino

may have up to 100 crimps per inch, while the coarser wools like karakul may have as few as

1 to 2. Hair, by contrast, has little if any scale and no crimp, and little ability to bind into

yarn. On sheep, the hair part of the fleece is called kemp. The relative amounts of kemp to

wool vary from breed to breed, and make some fleeces more desirable for spinning, felting,

or carding into batts for quilts or other insulating products, including the famous tweed cloth

of Scotland.

Wool fibres are hydrophilic, meaning they readily absorb moisture, but are not hollow.[4]

Wool can absorb moisture almost one-third of its own weight.[5]

Wool absorbs sound like

many other fabrics. It is generally a creamy white colour, although some breeds of sheep

produce natural colours, such as black, brown, silver, and random mixes.

Wool ignites at a higher temperature than cotton and some synthetic fibres. It has lower rate

of flame spread, low heat release, low heat of combustion, and does not melt or drip;[6]

it

forms a char which is insulating and self-extinguishing, and contributes less to toxic gases

and smoke than other flooring products, when used in carpets.[7]

Wool carpets are specified

for high safety environments, such as trains and aircraft. Wool is usually specified for

garments for firefighters, soldiers, and others in occupations where they are exposed to the

likelihood of fire.[7]

Wool is resistant to static electricity, as the moisture retained within the fabric conducts

electricity, so wool garments are much less likely to spark or cling to the body. The use of

woollen car seatcovers or carpets reduces the risk of a shock when a person touches a

grounded object. Wool is considered by the medical profession to be hypoallergenic.[7]

Processing

Shearing

Fine Merino shearing Lismore, Victoria

Sheep shearing is the process by which the woollen fleece of a sheep is cut off.

After shearing, the wool is separated into four main categories: fleece (which makes up the

vast bulk), broken, bellies, and locks.[8]

The quality of fleeces is determined by a technique

known as wool classing, whereby a qualified person called a wool classer groups wools of

similar gradings together to maximize the return for the farmer or sheep owner. In Australia

and New Zealand, before being auctioned, all Merino fleece wool is objectively measured for

micron, yield (including the amount of vegetable matter), staple length, staple strength, and

sometimes colour and comfort factor.

Scouring

Wool straight off a sheep, known as "greasy wool"[9]

or "wool in the grease", contains a high

level of valuable lanolin, as well as dirt, dead skin, sweat residue, pesticide, and vegetable

matter. Before the wool can be used for commercial purposes, it must be scoured, a process

of cleaning the greasy wool. Scouring may be as simple as a bath in warm water, or as

complicated as an industrial process using detergent and alkali, and specialized equipment.[10]

In commercial wool, vegetable matter is often removed by chemical carbonization.[11]

In less-

processed wools, vegetable matter may be removed by hand, and some of the lanolin left

intact through use of gentler detergents. This semigrease wool can be worked into yarn and

knitted into particularly water-resistant mittens or sweaters, such as those of the Aran Island

fishermen. Lanolin removed from wool is widely used in cosmetic products such as hand

creams.

Nylon is a generic designation for a family of synthetic polymers known generically as

polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research

facility at the DuPont Experimental Station. Nylon is one of the most commonly used

polymers.

Overview

Nylon is a thermoplastic, silky material, first used commercially in a nylon-bristled

toothbrush (1938), followed more famously by women's stockings ("nylons"; 1940). Nylon is

made of repeating units linked by amide bonds and is frequently referred to as polyamide

(PA). Nylon was the first commercially successful synthetic polymer. There are two common

methods of making nylon for fiber applications. In one approach, molecules with an acid (-

COOH) group on each end are reacted with molecules containing amine (-NH2) groups on

each end. The resulting nylon is named on the basis of the number of carbon atoms separating

the two acid groups and the two amines. These are formed into monomers of intermediate

molecular weight, which are then reacted to form long polymer chains.

Nylon was intended to be a synthetic replacement for silk and substituted for it in many

different products after silk became scarce during World War II. It replaced silk in military

applications such as parachutes and flak vests, and was used in many types of vehicle tires.

Nylon fibers are used in many applications, including fabrics, bridal veils, carpets, musical

strings, and rope.

Solid nylon is used for mechanical parts such as machine screws, gears and other low- to

medium-stress components previously cast in metal. Engineering-grade nylon is processed by

extrusion, casting, and injection molding. Solid nylon is used in hair combs. Type 6,6 Nylon

101 is the most common commercial grade of nylon, and Nylon 6 is the most common

commercial grade of molded nylon. For use in tools such as the spudger, a nylon is available

in glass-filled variants which increase structural and impact strength and rigidity, and

molybdenum sulfide-filled variants which increase lubricity.

Aramids are another type of polyamide with quite different chain structures which include

aromatic groups in the main chain. Such polymers make excellent ballistic fibers.

Chemistry

Nylons are condensation copolymers formed by reacting equal parts of a diamine and a

dicarboxylic acid, so that amides are formed at both ends of each monomer in a process

analogous to polypeptide biopolymers. Chemical elements included are carbon, hydrogen,

nitrogen, and oxygen. The numerical suffix specifies the numbers of carbons donated by the

monomers; the diamine first and the diacid second. The most common variant is nylon 6-6

which refers to the fact that the diamine (hexamethylene diamine, IUPAC name: hexane-1,6-

diamine) and the diacid (adipic acid, IUPAC name: hexanedioic acid) each donate 6 carbons

to the polymer chain. As with other regular copolymers like polyesters and polyurethanes, the

"repeating unit" consists of one of each monomer, so that they alternate in the chain. Since

each monomer in this copolymer has the same reactive group on both ends, the direction of

the amide bond reverses between each monomer, unlike natural polyamide proteins which

have overall directionality: C terminal → N terminal. In the laboratory, nylon 6-6 can also be

made using adipoyl chloride instead of adipic.

It is difficult to get the proportions exactly correct, and deviations can lead to chain

termination at molecular weights less than a desirable 10,000 daltons (u). To overcome this

problem, a crystalline, solid "nylon salt" can be formed at room temperature, using an exact

1:1 ratio of the acid and the base to neutralize each other. Heated to 285 °C (545 °F), the salt

reacts to form nylon polymer. Above 20,000 daltons, it is impossible to spin the chains into

yarn, so to combat this, some acetic acid is added to react with a free amine end group during

polymer elongation to limit the molecular weight. In practice, and especially for 6,6, the

monomers are often combined in a water solution. The water used to make the solution is

evaporated under controlled conditions, and the increasing concentration of "salt" is

polymerized to the final molecular weight.

DuPont patented[1]

nylon 6,6, so in order to compete, other companies (particularly the

German BASF) developed the homopolymer nylon 6, or polycaprolactam — not a

condensation polymer, but formed by a ring-opening polymerization (alternatively made by

polymerizing aminocaproic acid). The peptide bond within the caprolactam is broken with

the exposed active groups on each side being incorporated into two new bonds as the

monomer becomes part of the polymer backbone. In this case, all amide bonds lie in the same

direction, but the properties of nylon 6 are sometimes indistinguishable from those of

nylon 6,6 — except for melt temperature and some fiber properties in products like carpets

and textiles. There is also nylon 9.

The 428 °F (220 °C) melting point of nylon 6 is lower than the 509 °F (265 °C) melting point

of nylon 6,6.[2]

Nylon 5,10, made from pentamethylene diamine and sebacic acid, was studied by Carothers

even before nylon 6,6 and has superior properties, but is more expensive to make. In keeping

with this naming convention, "nylon 6,12" (N-6,12) or "PA-6,12" is a copolymer of a 6C

diamine and a 12C diacid. Similarly for N-5,10 N-6,11; N-10,12, etc. Other nylons include

copolymerized dicarboxylic acid/diamine products that are not based upon the monomers

listed above. For example, some aromatic nylons are polymerized with the addition of diacids

like terephthalic acid (→ Kevlar, Twaron) or isophthalic acid (→ Nomex), more commonly

associated with polyesters. There are copolymers of N-6,6/N6; copolymers of N-6,6/N-6/N-

12; and others. Because of the way polyamides are formed, nylon would seem to be limited to

unbranched, straight chains. But "star" branched nylon can be produced by the condensation

of dicarboxylic acids with polyamines having three or more amino groups.

The general reaction is:

A molecule of water is given off and the nylon is formed. Its properties are determined by the

R and R' groups in the monomers. In nylon 6,6, R = 4C and R' = 6C alkanes, but one also has

to include the two carboxyl carbons in the diacid to get the number it donates to the chain. In

Kevlar, both R and R' are benzene rings.

Concepts of nylon production

The first approach: combining molecules with an acid (COOH) group on each end are reacted

with two chemicals that contain amine (NH2) groups on each end. This process creates nylon

6,6, made of hexamethylene diamine with six carbon atoms and adipic acid.

The second approach: a compound has an acid at one end and an amine at the other and is

polymerized to form a chain with repeating units of (-NH-[CH2]n-CO-)x. In other words,

nylon 6 is made from a single six-carbon substance called caprolactam. In this equation, if n

= 5, then nylon 6 is the assigned name (may also be referred to as polymer).

The characteristic features of nylon 6,6 include:

Pleats and creases can be heat-set at higher temperatures More compact molecular structure Better weathering properties; better sunlight resistance Softer "Hand" Higher melting point (256 °C/492.8 °F) Superior colorfastness Excellent abrasion resistance

On the other hand, nylon 6 is easy to dye, more readily fades; it has a higher impact

resistance, a more rapid moisture absorption, greater elasticity and elastic recovery.

Characteristics

Variation of luster: nylon has the ability to be very lustrous, semilustrous or dull. Durability: its high tenacity fibers are used for seatbelts, tire cords, ballistic cloth and other

uses. High elongation Excellent abrasion resistance Highly resilient (nylon fabrics are heat-set) Paved the way for easy-care garments High resistance to insects, fungi, animals, as well as molds, mildew, rot and many chemicals Used in carpets and nylon stockings Melts instead of burning Used in many military applications Good specific strength Transparent to infrared light (−12dB)[3]

Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the

seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The

botanical purpose of cotton fiber is to aid in seed dispersal.

The plant is a shrub native to tropical and subtropical regions around the world, including the

Americas, Africa, and India. The greatest diversity of wild cotton species is found in Mexico,

followed by Australia and Africa.[1]

Cotton was independently domesticated in the Old and

New Worlds. The English name derives from the Arabic (al) qutn قطن, which began to be

used circa 1400 AD.[2]

The fiber is most often spun into yarn or thread and used to make a soft, breathable textile.

The use of cotton for fabric is known to date to prehistoric times; fragments of cotton fabric

dated from 5000 BC have been excavated in Mexico and Pakistan. Although cultivated since

antiquity, it was the invention of the cotton gin that so lowered the cost of production that led

to its widespread use, and it is the most widely used natural fiber cloth in clothing today.

Current estimates for world production are about 25 million tonnes annually, accounting for

2.5% of the world's arable land. China is the world's largest producer of cotton, but most of

this is used domestically. The United States has been the largest exporter for many years.[3]

Types of cotton There are four commercially-grown species of cotton, all domesticated in antiquity:

Gossypium hirsutum – upland cotton, native to Central America, Mexico, the Caribbean and southern Florida, (90% of world production)

Gossypium barbadense – known as extra-long staple cotton, native to tropical South America (8% of world production)

Gossypium arboreum – tree cotton, native to India and Pakistan (less than 2%) Gossypium herbaceum – Levant cotton, native to southern Africa and the Arabian Peninsula

(less than 2%)

The two New World cotton species account for the vast majority of modern cotton

production, but the two Old World species were widely used before the 1900s. While cotton

fibers occur naturally in colors of white, brown, and green, fears of contaminating the

genetics of white cotton have led many cotton-growing locations to ban growing of colored

cotton varieties which remain a specialty product.

History Cotton was first cultivated in the Old World 7,000 years ago (5th millennium BC), by the inhabitants

of western Pakistan, for example as the site of Mehrgarh where early cotton thread has been

preserved in copper beads.[4] Cotton cultivation became more widespread during the Indus Valley

Civilization, which covered a huge swath of the northwestern part of the South Asia, comprising

today parts of eastern Pakistan and northwestern India.[5] The Indus cotton industry was well

developed and some methods used in cotton spinning and fabrication continued to be used until the

modern industrialization of India.[6] Between 2000 and 1000 BC cotton became widespread in much

of India.[7] For example, it has been found at the site of Hallus in Karnataka around 1000 BC. Well

before the Common Era, the use of cotton textiles had spread from India to the Mediterranean and

beyond.[8]

Cotton fabrics discovered in a cave near Tehuacán, Mexico have been dated to around 5800

BC, although it is difficult to know for certain due to fiber decay.[9]

Other sources date the

domestication of cotton in Mexico to approximately 5000 to 3000 BC.[10]

The Greeks and the Arabs were not familiar with cotton until the Wars of Alexander the

Great, as his contemporary Megasthenes told Seleucus I Nicator of "there being trees on

which wool grows" in "Indica".

According to the Columbia Encyclopedia:[8]

Cotton has been spun, woven, and dyed since prehistoric times. It clothed the people of ancient

India, Egypt, and China. Hundreds of years before the Christian era, cotton textiles were woven in

India with matchless skill, and their use spread to the Mediterranean countries.

In Iran (Persia), the history of cotton dates back to the Achaemenid era (5th century BC);

however, there are few sources about the planting of cotton in pre-Islamic Iran. The planting

of cotton was common in Merv, Ray and Pars of Iran. In the poems of Persian poets,

especially Ferdowsi's Shahname, there are references to cotton ("panbe" in Persian). Marco

Polo (13th century) refers to the major products of Persia, including cotton. John Chardin, a

French traveler of 17th century, who had visited the Safavid Persia, has approved the vast

cotton farms of Persia.[11]

During the Han dynasty, cotton was grown by non Chinese peoples in the southern Chinese

province of Yunnan.[12]

In Peru, cultivation of the indigenous cotton species Gossypium barbadense was the

backbone of the development of coastal cultures, such as the Norte Chico, Moche and Nazca.

Cotton was grown upriver, made into nets and traded with fishing villages along the coast for

large supplies of fish. The Spanish who came to Mexico and Peru in the early 16th century

found the people growing cotton and wearing clothing made of it.

During the late medieval period, cotton became known as an imported fiber in northern

Europe, without any knowledge of how it was derived, other than that it was a plant; noting

its similarities to wool, people in the region could only imagine that cotton must be produced

by plant-borne sheep. John Mandeville, writing in 1350, stated as fact the now-preposterous

belief: "There grew there [India] a wonderful tree which bore tiny lambs on the endes of its

branches. These branches were so pliable that they bent down to allow the lambs to feed

when they are hungrie [sic]." (See Vegetable Lamb of Tartary.) This aspect is retained in the

name for cotton in many European languages, such as German Baumwolle, which translates

as "tree wool" (Baum means "tree"; Wolle means "wool"). By the end of the 16th century,

cotton was cultivated throughout the warmer regions in Asia and the Americas.

India's cotton-processing sector gradually declined during British expansion in India and the

establishment of colonial rule during the late 18th and early 19th centuries. This was largely

due to aggressive colonialist mercantile policies of the British East India Company, which

made cotton processing and manufacturing workshops in India uncompetitive. Indian markets

were increasingly forced to supply only raw cotton and were forced, by British-imposed law,

to purchase manufactured textiles from Britain.

Jute is a long, soft, shiny vegetable fibre that can be spun into coarse, strong threads. It is

produced from plants in the genus Corchorus, which has been classified in the family

Tiliaceae, or more recently in Malvaceae. However, it has been reclassified within the family

Sparrmanniaceae.

Jute is one of the most affordable natural fibres and is second only to cotton in amount

produced and variety of uses of vegetable fibres. Jute fibres are composed primarily of the

plant materials cellulose (major component of plant fibre) and lignin (major components of

wood fibre). It is thus a ligno-cellulosic fibre that is partially a textile fibre and partially

wood. It falls into the bast fibre category (fibre collected from bast or skin of the plant) along

with kenaf, industrial hemp, flax (linen), ramie, etc. The industrial term for jute fibre is raw

jute. The fibres are off-white to brown, and 1–4 metres (3–12 feet) long.

Cultivation

Main article: Jute cultivation

Jute plants (Corchorus olitorius and Corchorus capsularis)

Jute needs a plain alluvial soil and standing water. The suitable climate for growing jute

(warm and wet climate) is offered by the monsoon climate during the monsoon season.

Temperatures from 20˚C to 40˚C and relative humidity of 70%–80% are favourable for

successful cultivation. Jute requires 5–8 cm of rainfall weekly and more during the sowing

period.

White jute (Corchorus capsularis)

Several historical documents (including, Ain-e-Akbari by Abul Fazal in 1590) state that the

poor villagers of India used to wear clothes made of jute. Simple handlooms and hand

spinning wheels were used by the weavers, who used to spin cotton yarns as well. History

also states that Indians, especially Bengalis, used ropes and twines made of white jute from

ancient times for household and other uses.

Tossa jute (Corchorus olitorius)

Tossa jute (Corchorus olitorius) is an Afro-Arabian variety. It is quite popular for its leaves

that are used as an ingredient in a mucilaginous potherb called molokhiya (ملوخية a word of

uncertain etymology), popular in certain Arab countries. The Book of Job in the Hebrew

Bible mentions this vegetable potherb as Jew's mallow.[citation needed]

Tossa jute fibre is softer, silkier, and stronger than white jute. This variety astonishingly

showed good sustainability in the climate of the Ganges Delta. Along with white jute, tossa

jute has also been cultivated in the soil of Bengal where it is known as paat from the start of

the 19th century. Currently, the Bengal region (West Bengal in India, and Bangladesh) is the

largest global producer of the tossa jute variety.

Jute Fiber

History

For centuries, jute has been an integral part of culture of Bengal, in the entire southwest of

Bangladesh and some portions of West Bengal. During the British Raj in the 19th and early

20th centuries, much of the raw jute fibre of Bengal was carried off to the United Kingdom,

where it was then processed in mills concentrated in Dundee. Initially, due to its texture, it

could only be processed by hand until it was discovered in that city that by treating it with

whale oil, it could be treated by machine[1]

The industry boomed ("jute weaver" was a

recognised trade occupation in the 1901 UK census), but this trade had largely ceased by

about 1970 due to the appearance of synthetic fibres.

Margaret Donnelly, a jute mill landowner in Dundee in the 1800s, set up the first jute mills in

Bengal. In the 1950s and 1960s, when nylon and polythene were rarely used, one of the

primary sources of foreign exchange earnings for the erstwhile United Pakistan was the

export of jute products, based on jute grown in then East Bengal now Bangladesh. Jute has

been called the "Golden Fibre of Bangladesh." However, as the use of polythene and other

synthetic materials as a substitute for jute increasingly captured the market, the jute industry

in general experienced a decline.

During some years in the 1980s, farmers in Bangladesh burnt their jute crops when an

adequate price could not be obtained. Many jute exporters diversified away from jute to other

commodities. Jute-related organisations and government bodies were also forced to close,

change or downsize. The long decline in demand forced the largest jute mill in the world

(Adamjee Jute Mills) to close in Bangladesh. Bangladesh's second largest mill, Latif Bawany

Jute Mills, formerly owned by businessman, Yahya Bawany, was nationalized by the

government. Farmers in Bangladesh have not completely ceased growing jute, however,

mainly due to demand in the internal market. Between 2004–2010, the jute market recovered

and the price of raw jute increased more than 500%[citation needed]

.

Jute has entered many diverse sectors of industry, where natural fibres are gradually

becoming better substitutes. Among these industries are paper, celluloid products (films),

non-woven textiles, composites, (pseudo-wood), and geotextiles. In 2006, the General

Assembly of the United Nations proclaimed 2009 to be the International Year of Natural

Fibres, so as to raise the profile of jute and other natural fibres.

Production

Jute is a rain-fed crop with little need for fertilizer or pesticides. The production is

concentrated in India and some in Bangladesh, mainly Bengal. The jute fibre comes from the

stem and ribbon (outer skin) of the jute plant. The fibres are first extracted by retting. The

retting process consists of bundling jute stems together and immersing them in slow running

water. There are two types of retting: stem and ribbon. After the retting process, stripping

begins. Women and children usually do this job. In the stripping process, non-fibrous matter

is scraped off, then the workers dig in and grab the fibres from within the jute stem.[2]

India,

Pakistan, China are the large buyers of local jute while Britain, Spain, Ivory Coast, Germany

and Brazil also import raw jute from Bangladesh. India is the world's largest jute growing

country.

Polyester is a category of polymers which contain the ester functional group in their main

chain. Although there are many polyesters, the term "polyester" as a specific material most

commonly refers to polyethylene terephthalate (PET). Polyesters include naturally occurring

chemicals, such as in the cutin of plant cuticles, as well as synthetics through step-growth

polymerization such as polycarbonate and polybutyrate. Natural polyesters and a few

synthetic ones are biodegradable, but most synthetic polyesters are not.

Depending on the chemical structure, polyester can be a thermoplastic or thermoset; however,

the most common polyesters are thermoplastics.[1]

Fabric balls knitted from polyester thread or yarn are used extensively in apparel and home

furnishings, from shirts and pants to jackets and hats, bed sheets, blankets, upholstered

furniture and computer mouse mats. Industrial polyester fibers, yarns and ropes are used in

tyre reinforcements, fabrics for conveyor belts, safety belts, coated fabrics and plastic

reinforcements with high-energy absorption. Polyester fiber is used as cushioning and

insulating material in pillows, comforters and upholstery padding. Polyesters are also used to

make bottles, films, tarpaulin, canoes, liquid crystal displays, holograms, filters, dielectric

film for capacitors, film insulation for wire and insulating tapes. Polyesters are widely used as

a finish on high-quality wood products such as guitars, pianos and vehicle/yacht interiors.

Thixotropic properties of spray-applicable polyesters make them ideal for use on open-grain

timbers, as they can quickly fill wood grain, with a high-build film thickness per coat. Cured

polyesters can be sanded and polished to a high-gloss, durable finish.

While synthetic clothing in general is perceived by many as having a less natural feel

compared to fabrics woven from natural fibres (such as cotton and wool)[citation needed]

,

polyester fabrics can provide specific advantages over natural fabrics, such as improved

wrinkle resistance, durability and high color retention. As a result, polyester fibres are

sometimes spun together with natural fibres to produce a cloth with blended properties.

Synthetic fibres also can create materials with superior water, wind and environmental

resistance compared to plant-derived fibres.

Liquid crystalline polyesters are among the first industrially used liquid crystal polymers.

They are used for their mechanical properties and heat-resistance. These traits are also

important in their application as an abradable seal in jet engines[citation needed]

.

Types

Polyesters as thermoplastics may change shape after the application of heat. While

combustible at high temperatures, polyesters tend to shrink away from flames and self-

extinguish upon ignition. Polyester fibres have high tenacity and E-modulus as well as low

water absorption and minimal shrinkage in comparison with other industrial fibres.

Unsaturated polyesters (UPR) are thermosetting resins. They are used as casting materials,

fiberglass laminating resins and non-metallic auto-body fillers. Fibreglass-reinforced

unsaturated polyesters find wide application in bodies of yachts and as body parts of cars.

Increasing the aromatic parts of polyesters increases their glass transition temperature,

melting temperature, thermal stability, chemical stability...

Polyesters can also be telechelic oligomers like the polycaprolactone diol (PCL) and the

polyethylene adipate diol (PEA). They are then used as prepolymers.

Industry Basics

Polyester is a synthetic polymer made of purified terephthalic acid (PTA) or its dimethyl ester

dimethyl terephthalate (DMT) and monoethylene glycol (MEG). With 18% market share of

all plastic materials produced, it ranges third after polyethylene (33.5%)[citation needed]

and

polypropylene (19.5%).

The main raw materials are described as follows: Purified terephthalic acid – PTA – CAS-No.: 100-21-0

Synonym: 1,4 benzenedicarboxylic acid,

Sum formula; C6H4(COOH)2 , mol weight: 166.13

Dimethylterephthalate – DMT – CAS-No: 120-61-6 Synonym: 1,4 benzenedicarboxylic acid dimethyl ester

Sum formula C6H4(COOCH3)2 , mol weight: 194.19

Mono Ethylene Glycol – MEG – CAS No.: 107-21-1 Synonym: 1,2 ethanediol

Sum formula: C2H6O2 , mol weight: 62,07

To make a polymer of high molecular weight a catalyst is needed. The most common catalyst

is antimony trioxide (or antimony tri acetate):

Antimony trioxide – ATO – CAS-No.: 1309-64-4 Molecular weight: 291.51 Sum formula:

Sb2O3

In 2008, about 10,000 tonnes Sb2O3 were used to produce around 49 million tonnes

polyethylene terephthalate.[citation needed]

Polyester is described as follows:

Polyethylene Terephthalate CAS-No.: 25038-59-9 Synonym/abbreviations: polyester, PET,

PES Sum Formula: H-[C10H8O4]-n=60–120 OH, molelcular unit weight: 192.17

There are several reasons for the importance of Polyester:

The relatively easy accessible raw materials PTA or DMT and MEG The very well understood and described simple chemical process of polyester synthesis The low toxicity level of all raw materials and side products during polyester production and

processing The possibility to produce PET in a closed loop at low emissions to the environment The outstanding mechanical and chemical properties of polyester The recyclability The wide variety of intermediate and final products made of polyester.

In table 1 the estimated world polyester production is shown. Main applications are textile

polyester, bottle polyester resin, film polyester mainly for packaging and specialty polyesters

for engineering plastics. According to this table, the world's total polyester production might

exceed 50 million tons per annum before the year 2010.

Table 1: World polyester production

Market size per year

Product type 2002 [Million tonnes/year] 2008 [Million tonnes/year]

Textile-PET 20 39

Resin, bottle/A-PET 9 16

Film-PET 1.2 1.5

Special polyester 1 2.5

Total 31.2 49

Raw material producer

The raw materials PTA, DMT, and MEG are mainly produced by large chemical companies

which are sometimes integrated down to the crude oil refinery where p-Xylene is the base

material to produce PTA and liquefied petroleum gas (LPG) is the base material to produce

MEG.[citation needed]

Polyester processing

After the first stage of polymer production in the melt phase, the product stream divides into

two different application areas which are mainly textile applications and packaging

applications. In table 2, the main applications of textile and packaging of polyester is listed.

Table 2: Textile and packaging polyester application list

Polyester-based polymer (melt or pellet)

Textile Packaging

Staple fiber (PSF) Bottles for CSD, Water, Beer, Juice, Detergents

Filaments POY, DTY, FDY A-PET Film

Technical yarn and tire cord Thermoforming

Non-woven and spunbond BO-PET Biaxial oriented Film

Mono-filament Strapping

Abbreviations: PSF = Polyester Staple Fiber; POY = Partially Oriented Yarn; DTY = Draw

Textured Yarn; FDY = Fully Drawn Yarn; CSD = Carbonated Soft Drink; A-PET =

Amorphous Polyester Film; BO-PET = Biaxial Oriented Polyester Film;

A comparable small market segment (much less than 1 million tonnes/year) of polyester is

used to produce engineering plastics and masterbatch.

In order to produce the polyester melt with a high efficiency, high-output processing steps

like staple fiber (50–300 tonnes/day per spinning line) or POY /FDY (up to 600 tonnes/day

split into about 10 spinning machines) are meanwhile more and more vertically integrated

direct processes. This means the polymer melt is directly converted into the textile fibers or

filaments without the common step of pelletizing. We are talking about full vertical

integration when polyester is produced at one site starting from crude oil or distillation

products in the chain oil → benzene → PX → PTA → PET melt → fiber/filament or bottle-

grade resin. Such integrated processes are meanwhile established in more or less interrupted

processes at one production site. Eastman Chemicals were the first to introduce the idea of

closing the chain from PX to PET resin with their so-called INTEGREX process. The

capacity of such vertically integrated production sites is >1000 tonnes/day and can easily

reach 2500 tonnes/day.

Besides the above mentioned large processing units to produce staple fiber or yarns, there are

ten thousands of small and very small processing plants, so that one can estimate that

polyester is processed and recycled in more than 10 000 plants around the globe. This is

without counting all the companies involved in the supply industry, beginning with

engineering and processing machines and ending with special additives, stabilizers and

colors. This is a gigantic industry complex and it is still growing by 4–8% per annum,

depending on the world region. Useful information about the polyester industry can be found

under [2]

where a “Who is Producing What in the Polyester Industry” is gradually being

developed.

Synthesis

Synthesis of polyesters is generally achieved by a polycondensation reaction. See

"condensation reactions in polymer chemistry". The general equation for the reaction of a

diol with a diacid is :

(n+1) R(OH)2 + n R´(COOH)2 → HO[ROOCR´COO]nROH + 2n H2O

Azeotrope esterification

In this classical method, an alcohol and a carboxylic acid react to form a carboxylic ester. To

assemble a polymer, the water formed by the reaction must be continually removed by

azeotrope distillation.

Alcoholic transesterification

Main article: Transesterification

Transesterification: An alcohol-terminated oligomer and an ester-terminated oligomer condense to

form an ester linkage, with loss of an alcohol. R and R' are the two oligomer chains, R'' is a sacrificial

unit such as a methyl group (methanol is the byproduct of the esterification reaction).

Acylation (HCl method)

The acid begins as an acid chloride, and thus the polycondensation proceeds with emission of

hydrochloric acid (HCl) instead of water. This method can be carried out in solution or as an

enamel.

Silyl method

In this variant of the HCl method, the carboxylic acid chloride is converted with the trimethyl

silyl ether of the alcohol component and production of trimethyl silyl chloride is obtained

Acetate method (esterification)

Silyl acetate method

Ring-opening polymerization

Aliphatic polyesters can be assembled from lactones under very mild conditions, catalyzed

anionically, cationically or metallorganically. A number of catalytic methods for the

copolymerization of epoxides with cyclic anhydrides have also recently been shown to

provide a wide array of functionalized polyesters, both saturated and unsaturated.

Cross-linking

Unsaturated polyesters are thermosetting resins. They are generally copolymers prepared by

polymerizing one or more diol with saturated and unsaturated dicarboxylic acids (maleic

acid, fumaric acid...) or their anhydrides. The double bond of unsaturated polyesters reacts

with a vinyl monomer mainly the styrene, resulting in a 3-D cross-linked structure. This

structure acts as a thermoset. The cross-linking is initiated through an exothermic reaction

involving an organic peroxide, such as methyl ethyl ketone peroxide or benzoyl peroxide.

Geometric Shapes in Architecture

Introduction

Man has always needed shelter. In the earliest days men were nomads whose main occupations

were hunting and fishing. In order to survive they moved from place to place very frequently. They

were content to live in caves and other temporary shelters. With the advent of agriculture, men

were able to settle in more permanent locations, and they built lasting structures to use as homes. It

was then that architecture came into being.

As years passed, man�s knowledge grew and principles of construction improved. No

longer were men satisfied to build houses alone. Now they designed tombs in which to be

buried, monuments to serve as memorials, palaces to house the rulers, and churches where

they could worship their gods. To produce structures that were functional as well as models

of architectural beauty, designers had to apply principles of mathematics in their work.

Proper ratios and proportions related each feature of a building with every other one and with

the whole structure. Various geometric shapes provided maximum use as well as a pleasing

appearance in all types of architecture.

At the present time, many school children in New Haven are unaware of the relation between

the mathematics studied in their classrooms and the architecture that surrounds them

throughout the city. They shop in the Chapel Square Mall without noticing the simple lines

and planes that form the pattern of the building. On their way to concerts in the Veterans�

Memorial Coliseum, they pass the Supreme Headquarters of the Knights of Columbus and

refer to its cylindrical columns as �tootsie rolls�. The Ingalls rink, commonly known as

�the whale�, stirs up lively conversations about ice skating and hockey without any

thought that the backbone of �the whale� is a perfect sine curve. Many Saturday afternoons

are spent enjoying football in the elliptical stadium known as Yale Bowl. History students,

who visit the graves of notable men in Grove Street Cemetery, seem to be oblivious of the

fact that the lovely entrance gate is a trapezoid. When they are visiting friends� homes,

young people are too busy to see the wide variety of geometric shapes and designs that

abound both outside and inside

In this unit of study we will try to improve the students� understanding and appreciation of

basic geometric shapes that are used in architecture. me unit will describe various plane

geometric figures. It will discuss in detail the properties of several of these figures.

Perimeters and areas of polygons and circles will be computed.

There are several basic objectives for this unit of

study. Upon completion of the unit, the student will be

able to:

�appreciate and enjoy the beauty and charm that exist in the architecture that surrounds him.

�identify simple geometric figures.

�understand the properties of polygons and circles.

�compute areas and perimeters of plane figures.

The material developed here may be used at the following levels of instruction: (1) in seventh

or eighth grade arithmetic classes; (2) in high school geometry classes; (3) in high school

applied mathematics classes; (4) in adult basic education classes.

Polygons

Polygons are evident in all architecture. They provide variation and charm in buildings. When applied

to manufactured articles such as printed fabrics, wallpapers, and tile flooring, polygons enhance the

beauty of the structure itself.

The word polygon is derived from the Greek words meaning many angles. A polygon is a

closed plane figure formed by three or more line segments which intersect only at their

endpoints. Each endpoint is common to exactly two segments.

Example: The figures below are polygons

(figure available in print form)

The following figures are not polygons.

(figure available in print form)

Segments that form a polygon are called sides of the polygon, and an endpoint of any side is

a vertex of the polygon. If two sides have a common endpoint, they are said to be

consecutive. The endpoints of one side are consecutive vertices. The angles of a polygon are

the interior angles between adjacent sides. A polygon is named by placing a capital letter on

each vertex, moving consecutively around the figure in either a clockwise or

counterclockwise direction. If a segment Joins two non consecutive vertices, it is called a

diagonal of the polygon.

Example: This is polygon ABCDE.

(figure available in print form)

Sides Vertices Consecutive Consecutive Angles Diagonals

Sides Vertices

AB A AB and BC A and B ABC AC

BC B BC and CD B and C BCD AD

CD C CD and DE C and D CDE BD

DE D DE and EA D and E DEA BE

EA E EA and AB E and A EAB CE

A polygon is convex if each interior angle is less than a straight angle, otherwise it is

concave. If all sides are equal, the polygon is equilateral, and if all angles are equal it is

equiangular. A regular polygon is both equilateral and equiangular.

Example: Convex Polygon Concave Polygon Regular Polygon

(figure available in print form)

Polygons are classified according to their sides.

No. of Sides Kind of Polygon No.of Sides Kind of Polygon

3 Triangle 7 Heptagon

4 Quadrilateral 8 Octagon

5 Pentagon 9 Nonagon

6 Hexagon 10 Decagon

Suggested Assignment: For one week keep a log of all the polygons that you observe at

home, on the way to school, and in school. Tell the kinds of polygons that you have seen, the

places where you have seen them, and their applications in everyday living.

Exercises:

1. Which of the following are polygons?

(figure available in print form)

2. Using letters name the following polygons.

(figure available in print form)

3. Name the sides, the angles, and the diagonals of each polygon in example 1.

4. Tell whether the following polygons are convex or concave.

(figure available in print form)

5. Classify each of the following polygons:

(figure available in print form)

6. Are the following polygons equilateral, equiangular, or regular?

(figure available in print form)

7. In the following picture identify as many polygons as possible.

(figure available in print form)

The polygons pictured here are:

______________

______________

______________

______________

______________

Triangles

The triangle is the simplest and one of the most familiar of all polygons. It is used in construction and

design of every description. We see it in the framework of buildings and bridges. Because it is a rigid

figure, the shape of a triangle cannot be changed when pressure is applied to it. For this reason the

triangle provides an excellent support for many structures.

A triangle is a polygon that has three sides. The symbol used to denote a triangle is � . An

altitude of a triangle is a segment drawn from a vertex perpendicular to the side opposite that

vertex, or perpendicular to that side extended. A median of a triangle is a segment drawn

from a vertex to the midpoint of the side opposite that vertex. Every triangle has three

altitudes and three medians.

Example:

Triangle ABC is shown.

CD is an altitude.

CE is a median.

As its name implies, a triangle has three angles. The sum of the three angles of a triangle is

180 degrees.

Triangles may be classified by their sides. A scalene triangle has no equal sides. An isosceles

triangle has two equal sides. The equal sides of the isosceles triangle are the legs and the

third side is the base of the triangle. If three sides of a triangle are equal, the triangle is

equilateral. In every triangle, the sum of any two sides is greater than the third side.

Triangles also may be classified by their angles. An acute triangle is a triangle in which each

angle is less than 90�. A right triangle contains one right angle. The sides that form the right

angle are called legs, and the side opposite the right angle is the hypotenuse of the triangle. If

a triangle contains one obtuse angle, it is an obtuse triangle. An equiangular triangle has

three equal angles.

There is a relationship between the number of equal sides and the number of equal angles in a

triangle. If all sides of a triangle are unequal, the angles opposite these sides are unequal in

the same order, that is, the largest angle is opposite the largest side, the middle angle is

opposite the middle side, and the smallest angle is opposite the smallest side.

In an isosceles triangle, the angles opposite the equal sides are equal. They are called base

angles, and the third angle of the isosceles triangle is the vertex angle. An equilateral triangle

is always equiangular.

Suggested Assignment: In your home or neighborhood, identify as many types of triangles as

you can. Name the places where triangles are used most often. For what purpose are triangles

used in architecture?

2.) The vertices of � MNP are ___, ___, and ___.

3.) If MR = RN, PR is a ___ of � MNP.

4.) If MT is perpendicular to PN, MT is an ___ of � MNP.

5.) In � ABC, A = 67� and B = 36� , C = ___�.

6.) Can the sides of a triangle be (a) 2�, 3�, 7�? (b) 4�, 5�, 6� ?

7.) In right triangle RST, S is the right angle. (a) The legs of � RST are ___ and ___. (b) The

hypotenuse of �RST is ___.

8.) In isosceles � XYZ, XY = XZ.

(a) The legs of � XYZ are ___ and ___.

(b) The base of � XYZ is ___.

(c) The base angles of � XYZ are ___ and ___.

(d) The vertex angle Of � xYz is ___.

9.) In � EFG, E=100�, F = 50�, and G = 30�

(a) The largest side of � EFG is ___.

(b) The smallest side of � EFG is ___.

Quadrilaterals

Another very familiar polygon used in architecture is the quadrilateral. Ceilings, floors, walls,

windows and doors usually are quadrilaterals. A quadrilateral is a polygon with four sides. The most

common quadrilaterals are the parallelogram, rectangle, square, rhombus, and trapezoid.

A parallelogram is a quadrilateral whose opposite sides are parallel. The symbol used to

denote a parallelogram is . A rhombus is an equilateral parallelogram. A rectangle is a

parallelogram with right angles. A square is an equilateral rectangle.

A trapezoid is a quadrilateral with exactly two parallel sides. The parallel sides of the

trapezoid are called the bases. The nonparallel sides are called the legs of the trapezoid. If the

legs are equal, the trapezoid is isosceles. A line segment drawn perpendicular to the bases is

an altitude of the trapezoid. The line segment Joining the midpoints of the legs is the median.

The length of the median is equal to one half the sum of the bases.

ABCD is a trapezoid.

AB and DC are the bases of the trapezoid.

AD and BC are the legs of the trapezoid.

DE is an altitude of the trapezoid.

MN is a median of the trapezoid.

Suggested Assignment: Make a bulletin board to display pictures of buildings cut out of

magazines. Identity all the geometric shapes that you see in the pictures. Describe how

geometric shapes are used as ornaments as well as parts of structural designs in architecture.

2.) ABCD is a parallelogram.

(a) The sum of the angles of � ABC is ___ degrees.

(b) The sum of the angles of � ADC is ___ degrees.

(c) The sum of the angles of � ABCD is ___ degrees.

3.) Measure the opposite sides of ABCD. The opposite sides of a parallelogram are ___.

4.) Measure the opposite angles of ABCD. The opposite angles of a parallelogram are ___.

5.) In parallelogram ABCD draw diagonals AC and BD intersecting at X. Measure DX, XB, AX, and XC.

DX and XB are ___. AX and XC are ___. The diagonals of a parallelogram ____ each other.

6.) Measure the diagonals of rectangle EFGH. The diagonals of a rectangle are ___.

7.) The bases of trapezoid QRST are 17� and 23� respectively. The length of the median of QRST is

___.

8.) Draw an isosceles trapezoid. Measure the base angles of the trapezoid. The base angles of an

isosceles trapezoid are ___.

9.) Draw the diagonals of rhombus EFGH. Measure the angles formed by the intersection of the

diagonals. The diagonals of a rhombus are ___ to each other.

Perimeter of a Polygon

The perimeter of a polygon is the distance around the �rim� or edge of the figure. Linear units

such as inches, feet, meters or miles are used to measure perimeter. To find the perimeter of a

polygon, add the lengths of all its sides.

Example:

Find the perimeter of a room that is 23 feet long and 15 feet wide.

Solution:

Perimeter 23 23 15 15 76 feet

5.) A rectangular swimming pool is 24 2/3 feet long and 15 5/6 feet wide. How many feet of fencing

are needed to enclose the pool?

6.) A room is 18.6 feet long and 12.4 feet wide. How many feet of molding are needed to go around

the rooms

Area of a Polygon

In designing homes, offices or other buildings, the amount of living area or working area is of

primary concern to the architect. The word area is used to indicate the measure of a surface. Square

units, such as square feet or square meters are the standard units used in measuring area. One

square unit is a square that measures one unit on each side. The area of any polygon is the number

of square units that are contained within the figure.

Area of a Rectangle

In a rectangle any side may be called a base. The altitude to the base, also known as the height of

the figure, is a segment drawn perpendicular to the base from a point on the opposite side. The

measures of the base and altitude are denoted by b and h respectively. Consecutive sides of a

rectangle are perpendicular.

(figure available in print form)

In rectangle EFGH, EF is the base, and HE is the altitude drawn to the base. When each side

of the rectangle is divided into unit segments, b 3 units and h 2 units. The number of square

units contained in the rectangle is six or three times two. Thus, the area of the rectangle

equals the product of the base and altitude.

Area of a Rectangle = Base x Altitude or A=bh

Example:

Find the area of a rectangle whose base is 8.4 cm. and whose altitude is 15.6 cm. in length.

Solution:

A= bh A= 8.4 x 15.6 =131.04 sq. ft.

Area of a Parallelogram

Consecutive sides of all parallelograms are not perpendicular. Although any side of a parallelogram

may be called a base, the altitude of a parallelogram is not always a side of the figure. In ABCD, AB is

the base and DE is an altitude drawn to AB. The formula to find the area of a parallelogram may be

derived as follows:

(figure available in print form)

Area of a Parallelogram = Base x Altitude or A=bh

Example:

Find the area of a parallelogram whose base is 8 1/2 inches and whose altitude is 15 1/4

inches in length.

Solution:

Area= 8 1/2 x 15 1/4 = 17/2 x 61/4= 1437/8 = 179 5/8 sq. in.

Area of a Triangle

The diagonal of a parallelogram divides the figure into two equal triangles. The area of each triangle

is equal to one half the area of the parallelogram.

(figure available in print form)

Area of ABCD = AB x h

Area of ABC= 1/2 X AB x h

Area of a triangle = 1/2 x base x altitude

A = 1/2 bh

Example:

Find the area of a triangle whose base is 23.9 ft. and whose altitude is 14.8 ft.

Solution:

A =1/2 bh A-1/2 x 23.9 x 14.8 =1/2 x 353.72 =176.86 sq.ft.

Area of a Trapezoid

Altitudes drawn from each endpoint of the upper base separate a trapezoid into three non

overlapping polygons-two triangles and a rectangle. The area of the trapezoid is equal to the sum of

the areas of these three polygons. A formula to find the area of a trapezoid may be derived as

follows:

(figure available in print form)

Area of a Trapezoid = 1/2 x Altitude x Sum of the Bases

Example:

Find the area of a trapezoid whose bases are 10 cm. and 14 cm. and whose altitude is 6 cm.

Iong.

Solution:

A = 1/2h(b1+ b2) A= 1/2 x 6(10 + 14)= 3 x 24= 72 sq. cm.

Suggested Assignment:

Using polygons, design a house or other building. Find the areas of the exterior walls, the

roof, the doors, and the windows.

9. At $8.50 a square yard, what is the cost of laying a cement floor in a garage that is 6 yards long

and 7 yards wide?

10. At $1.85 a square yard, find the cost of painting the front and rear gables of a house 18 ft. wide,

the height of the ridge above the eaves being 10 ft.

11. QRST is a rectangle. Find the area of:

(figure available in print form)

Circles:

Not all geometric figures are formed by straight lines. One of the most useful geometric shapes is

the circle. It plays a vital part in our lives�in wheels, in all sorts of containers, in machine parts, in

design, and in architecture. The circle provides the most economical form of shelter. Round houses

are used in the Arctic and at the equator.

A circle is the set of points in a plane equidistant from a fixed point in the plane called the

center. The circle receives its name from the center. O is the symbol used to denote a circle.

Several important terms are associated with the circle. A radius of a circle is a line segment

which Joins the center to any point on the circle. AB is a radius of circle A.

(figure available in print form)

A chord is a line segment whose endpoints lie on the circle. CD is a chord of circle A. A

diameter is a chord which passes through the center of the circle. CE is a diameter of circle

A. A secant is a line which intersects a circle in two points. FG is a secant of circle A.

A tangent is a line which lies in the plane of the circle and intersects the circle in exactly one

point. EJ is a tangent to circle A. The point of contact is the point at which the tangent

intersects the circle. ~ is the point of contact of tangent EJ. The circumference of a circle is

the perimeter or distance around the edge of the circle. An arc is a part of the circumference

of a circle. EB is an arc of circle A.

If the circumference of any circle is divided by its diameter, the quotient is always

approximately 22/7 or 3.14. This special number is represented by the Greek letter pi ().

Hence, the circumference of a circle may be expressed as the product of pi and the length of

the diameter of the circle. The formula for finding circumference is C = d or C = 2 r. The area

of a circle may be expressed as the product of pi and the square of the length of the radius, or

A = r2 .

Example:

Find the circumference and area of a circle whose diameter is 14 inches long.

Solution:

C = d A = r2

C = 22/7 x 14 A = 22/7 x 7 x 7

C = 44 inches A = 154 sq. in..

Suggested Assignment:

Write a report on circular houses used in Africa and in the Arctic.

Exercises:

1. Find the circumference and area of a circle whose radius is 5 1/4 feet long.

2. In circle X, identify the following parts:

a. RY e. Line ST

b. XZ f. Line UV

c. YW g. Point R

d. ZW h. Point X

(figure available in print form)

3. Illustrated below are floor plans of a round house, a square house, and a rectangular house. The

perimeter of each one is 66 feet. Find the area of each figure Which of the houses has the greatest

number of square feet of living area?

(figure available in print form)

4. Name the geometric figures that you see in the illustration of the door below at the left.

5. How many square inches of glass are necessary to fill the window shown below at the right?