Dome of the Rock
The Dome of the Rock is an Islamic shrine located on the Temple Mount in the Old City of Jerusalem. It was completed in 691–92 CE at the order of Umayyad Caliph Abd al-Malik during the Second Fitna on the site of the Second Jewish Temple, destroyed during the Roman Siege of Jerusalem in 70 CE; the original dome collapsed in 1015 and was rebuilt in 1022–23. The Dome of the Rock is in its core one of the oldest extant works of Islamic architecture, its architecture and mosaics were patterned after nearby Byzantine churches and palaces, although its outside appearance has been changed in the Ottoman period and again in the modern period, notably with the addition of the gold-plated roof, in 1959–61 and again in 1993. The octagonal plan of the structure may have been influenced by the Byzantine Church of the Seat of Mary built between 451 and 458 on the road between Jerusalem and Bethlehem; the Foundation Stone the temple was built over bears great significance in Judaism as the place where God created the world and the first human, Adam.
It is believed to be the site where Abraham attempted to sacrifice his son, as the place where God's divine presence is manifested more than in any other place, towards which Jews turn during prayer. The site's great significance for Muslims derives from traditions connecting it to the creation of the world and the belief that the Prophet Muhammad's Night Journey to heaven started from the rock at the center of the structure. A UNESCO World Heritage Site, it has been called "Jerusalem's most recognizable landmark," along with two nearby Old City structures, the Western Wall, the "Resurrection Rotunda" in the Church of the Holy Sepulchre; the structure is octagonal. It is capped at its centre by a dome 20 m in diameter, mounted on an elevated circular drum standing on 16 supports. Surrounding this circle is an octagonal arcade of 24 piers and columns; the octagonal arcade and the inner circular drum create an inner ambulatorium that encircles the holy rock. The outer walls are octagonal, they each measure 18 m wide and 11 m high.
The outer and inner octagon create a outer ambulatorium surrounding the inner one. Both the circular drum and the exterior walls contain many windows; the interior of the dome is lavishly decorated with mosaic and marble, much of, added several centuries after its completion. It contains Qur'anic inscriptions; the dedicatory inscription in Kufic script placed around the dome contains the date believed to be the year the Dome was first completed, AH 72, while the name of the corresponding caliph and builder of the Dome, al-Malik, was deleted and replaced by the name of Abbasid caliph Al-Ma'mun during whose reign renovations took place. Surah Ya Sin is inscribed across the top of the tile work and was commissioned in the 16th century by Suleiman the Magnificent. Al-Isra, the Surah 17 which tells the story of the Isra or Night Journey, is inscribed above this; the Dome of the Rock is situated in the center of the Temple Mount, the site of the Temple of Solomon and the Jewish Second Temple, expanded under Herod the Great in the 1st century BCE.
Herod's Temple was destroyed in 70 CE by the Romans, after the Bar Kokhba revolt in 135, a Roman temple to Jupiter Capitolinus was built at the site. Jerusalem was ruled by the Christian Byzantine Empire throughout the 4th to 6th centuries. During this time, Christian pilgrimage to Jerusalem began to develop; the Church of the Holy Sepulchre was built under Constantine in the 320s, but the Temple Mount was left undeveloped after a failed project of restoration of the Jewish Temple under Julian the Apostate. The initial octagonal structure and its round wooden dome had the same shape as is does today; the Dome of the Rock is now assumed to have been built by the order of Umayyad Caliph Abd al-Malik and his son and successor Al-Walid I. According to Sibt ibn al-Jawzi, construction started in 687. Construction cost was seven times the yearly tax income of Egypt. A dedicatory inscription in Kufic script is preserved inside the dome; the date is recorded as AH 72, the year historians believe the construction of the original Dome was completed.
In this inscription, the name of al-Malik was deleted and replaced by the name of Abbasid caliph Al-Ma'mun. This alteration of the original inscription was first noted by Melchior de Vogüé in 1864. An alternative interpretation claims that the inscription indicates the year when construction started; some scholars have suggested that the dome was added to an existing building, built either by Muawiyah I, or indeed a Byzantine building dating to before the Muslim conquest, built under Heraclius. Its architecture and mosaics were patterned after palaces; the two engineers in charge of the project were Raja ibn Haywah, a Muslim theologian from Beit She'an and Yazid Ibn Salam, a non-Arab, Muslim and a native of Jerusalem. Shelomo Dov Goitein of the Hebrew University has argued that the Dome of the Rock was intended to compete with the many fine buildings of worship of other religions: "The form of a rotunda, given to the Qubbat as-Sakhra, although it was foreign to Islam, was destined to rival the many Christian domes."
K. A. C. Creswell in his book The Origin of the Plan of the Dome of the Rock notes that those who built the shrine used the measurements of the Church of the Holy Sepulchre; the diameter of the dome of the shrine is 20.20 m and its height 20.48 m, while the diameter of the
Islamic architecture is the range of architectural styles of buildings associated with Islam. It encompasses religious styles from the early history of Islam to the present day. Early Islamic architecture was influenced by Roman, Persian and all other lands which the Muslims conquered in the 7th and 8th centuries. Further east, it was influenced by Chinese and Indian architecture as Islam spread to Southeast Asia, it developed distinct characteristics in the form of buildings, the decoration of surfaces with Islamic calligraphy and geometric and interlace patterned ornament. The principal Islamic architectural types for large or public buildings are: the Mosque, the Tomb, the Palace and the Fort. From these four types, the vocabulary of Islamic architecture is derived and used for other buildings such as public baths and domestic architecture. Many of the buildings which are mentioned in this article are listed as World Heritage Sites; some of them, like the Citadel of Aleppo, have suffered significant damage in the ongoing Syrian Civil War.
The most recent building that can be known as a true example modern of Islamic architecture is Imam Sadiq University, this building was the winner of Aga Khan fundation as well. This building designed by Nader Ardalan, Iranian architect teaching at Harvard University; the Dome of the Rock in Jerusalem is one of the most important buildings in all of Islamic architecture. It is patterned after the nearby Church of the Holy Sepulchre and Byzantine Christian artists were employed to create its elaborate mosaics against a golden background; the great epigraphic vine frieze was adapted from the pre-Islamic Syrian style. The Dome of the Rock featured interior vaulted spaces, a circular dome, the use of stylized repeating decorative arabesque patterns. Desert palaces in Jordan and Syria served the caliphs as living quarters, reception halls, baths, were decorated to promote an image of royal luxury; the horseshoe arch became a popular feature in Islamic structures. Some suggest the Muslims acquired this from the Visigoths in Spain but they may have obtained it from Syria and Persia where the horseshoe arch had been in use by the Byzantines.
In Moorish architecture, the curvature of the horseshoe arch is much more accentuated. Furthermore, alternating colours were added to accentuate the effect of its shape; this can be seen at a large scale in the Great Mosque of Córdoba. The Great Mosque of Damascus, built on the site of the basilica of John the Baptist after the Islamic invasion of Damascus, still bore great resemblance to 6th and 7th century Christian basilicas. Certain modifications were implemented, including expanding the structure along the transversal axis which better fit with the Islamic style of prayer; the Abbasid dynasty witnessed the movement of the capital from Damascus to Baghdad, from Baghdad to Samarra. The shift to Baghdad influenced politics and art; the Great Mosque of Samarra, once the largest in the world, was built for the new capital. Other major mosques built in the Abbasid Dynasty include the Mosque of Ibn Tulun in Cairo, Abu Dalaf in Iraq, the great mosque in Tunis. Abbasid architecture in Iraq as exemplified in the Fortress of Al-Ukhaidir demonstrated the "despotic and the pleasure-loving character of the dynasty" in its grand size but cramped living quarters.
The Great Mosque of Kairouan is considered the ancestor of all the mosques in the western Islamic world. Its original marble columns and sculptures were of Roman workmanship brought in from Carthage and other elements resemble Roman form, it is one of the best preserved and most significant examples of early great mosques, founded in 670 AD and dating in its present form from the Aghlabid period. The Great Mosque of Kairouan is constituted of a massive square minaret, a large courtyard surrounded by porticos and a huge hypostyle prayer hall covered on its axis by two cupolas; the Great Mosque of Samarra in Iraq, completed in 847 AD, combined the hypostyle architecture of rows of columns supporting a flat base above which a huge spiraling minaret was constructed. The Hagia Sophia in Istanbul influenced Islamic architecture; when the Ottomans captured the city from the Byzantines, they converted the basilica to a mosque and incorporated Byzantine architectural elements into their own work. The Hagia Sophia served as a model for many Ottoman mosques such as the Shehzade Mosque, the Suleiman Mosque, the Rüstem Pasha Mosque.
Domes are a major structural feature of Islamic architecture. The dome first appeared in Islamic architecture in 691 with the construction of the Dome of the Rock, a near replica of the existing Church of the Holy Sepulchre and other Christian domed basilicas situated nearby. Domes remain in use, being a significant feature of many mosques and of the Taj Mahal in the 17th century; the distinctive pointed domes of Islamic architecture originating with the Byzantines and Persians, have remained a distinguishing feature of mosques into the 21st century. Distinguishing motifs of Islamic architecture have always been the mathematical themes of ordered repetition, radiating structures, rhythmic, metric patterns. In this respect, fractal geometry has been a key utility for mosques and palaces. Other significant features employed as motifs include columns and arches, organized and interwoven with alternating sequences of niches and colonnettes. From the eighth to the eleventh century, Islamic architectural styles were influenced by two different ancien
Traditional Persian residential architecture
Traditional Persian residential architecture, is the architecture employed by builders and craftsmen in the cultural Greater Iran and the surrounding regions to construct vernacular houses. The art draws from various elements from both Islamic and pre-Islamic times. Being situated on the edge of deserts and arid regions, Persian cities have hot summers, cold, dry winters, thus Iran’s traditional architecture is designed in proportion to its climatic conditions. The continued design and existence of traditional homes amidst the preponderance of mid-rise apartments in Iran's ongoing modernisation projects is testament to a strong connection and identification with Persian architectural heritage. Iran's old city fabric is composed of narrow winding streets called koocheh with high walls of adobe and brick roofed at various intervals; this form of urban design, which used to be commonplace in Iran, is an optimal form of desert architecture that minimizes desert expansion and the effects of dust storms.
It maximizes daytime shades, insulates the “fabric” from severe winter temperatures. Islamic beliefs coupled with the necessity to defend cities against frequent foreign invasions encouraged traditional Persian residential architects to create inward seeking designs amidst these narrow complicated koochehs, weaving knit residential neighborhoods, thus the house becomes the container as opposed to the contained. These houses possess an innate system of protection. Hence residential architecture in Persia was designed in a way so as to provide maximum protection to the inhabitants during times of tension and danger, while furnishing a microcosm of tranquility that protected this inner “paradise garden”. Neighborhoods in old Persian cities formed around shrines of popular saints. All public facilities such as baths, houses of mourning, administration offices, schools were to be found within the neighborhood itself. In addition to the main bazaar of the city, each neighborhood had its own bazaar-cheh as well, as well as its own ab anbar, which provided the neighborhood with clean water.
Qazvin, for example had over 100 such reservoirs before being modernized with city plumbing in modern times. When visiting Kashan in 1993, the chairman of UNESCO remarked: “Kashani architects are the greatest alchemists of history, they could make gold out of dust”. Indeed all of Kashan's masterpieces, as in many other parts in Iran are made of humble, earth. Like many other cities throughout Iran, stucco was the most widespread method of ornamentation in Persian houses. One reason was the cheap price of the materials used that don't require a high temperature to be transformed into plaster; this is an important consideration in places like central Iran where wood is scarce. Another reason is that it is shaped, molded, or carved. Thanks to stucco, a wall of crudely fashioned stone blocks or raw brick, gives an impression of great luxury, thus stucco owes its luxurious appearance to the skill of the craftsman. And with a tradition of stucco technique going back to pre-Islamic Iran, this is an art mastered by Persian craftsmen, as seen here.
Earthquakes in Iran leave massive destruction. Most of Iran's remaining traditional houses date from the post-quake eras during the Qajar period. Despite the efforts of architects to build resistance to earthquakes into their works, hardly anything remains from the spectacular Safavi palaces or anything prior to those as recounted by French and British explorers in many parts of Persia. All traditional Persian houses were designed in order to satisfy the following essential features: Hashti and Dalan-e-vorudi: Entering the doorway one steps into a small enclosed transitional space called Hashti. Here one is forced to redirect one's steps away from the street and into the hallway, called Dalan e Vorudi. In mosques, the Hashti enables the architect to turn the steps of the believer to the correct orientation for prayer hence giving the opportunity to purify oneself before entering the mosque. Convenient access to all parts of the house. A central pool with surrounding gardens containing trees of figs and grape vines.
Important partitionings such as the biruni and the andaruni. Specific orientation facing toward and away from Mecca. Furthermore, Persian houses in central Iran were designed to make use of an ingenious systems of wind catchers that create unusually cool temperatures in the lower levels of the building. Thick massive walls were designed to keep the sun's heat out in the summertime while retaining the internal heat in the winters. Persia's distinctive artistic heritage with efficient yet ancient technical know-how thus created houses and spaces whose features were aesthetic talars and roofscapes with intriguing light wells, as well as intricate window and mirror works, reliefs, a beautifully crafted iwan amidst comfortable residential spaces in hot arid regions. Whereas the geometrical rigor seen in the works such as those in Safavi era Isfahan invoke the perfect order of the celestial world, the vegetal ornamentation realized in the interiors of houses, testify to the Persian love of gardens.
And the stucco carvings and paintings executed by royal craftsmen, exemplify the level of Persian aesthetics. Talar Iwan Dalan-e vorudi Badgir Qanat Kariz Gonbad Garden Shabestan Kucheh Panjdari Hashti Andaruni Biruni Ab anbar Yakhchal Howz Abbasian House House of Tabatabaei Amerian House Borujerdi ha House House of Qavam Tizno house in dezful
Iranian architecture or Persian architecture is the architecture of Iran and parts of the rest of West Asia, the Caucasus and Central Asia. Its history dates back to at least 5,000 BC with characteristic examples distributed over a vast area from Turkey and Iraq to Uzbekistan and Tajikistan, from the Caucasus to Zanzibar. Persian buildings vary from peasant huts to tea houses and garden, pavilions to "some of the most majestic structures the world has seen". In addition to historic gates and mosques, the rapid growth of cities such as the capital, Tehran has brought about a wave of demolition and new construction. Iranian architecture displays great variety, both structural and aesthetic, from a variety of traditions and experience. Without sudden innovations, despite the repeated trauma of invasions and cultural shocks, it has achieved "an individuality distinct from that of other Muslim countries", its paramount virtues are: "a marked feeling for scale. Traditionally, the guiding formative motif of Iranian architecture has been its cosmic symbolism "by which man is brought into communication and participation with the powers of heaven".
This theme has not only given unity and continuity to the architecture of Persia, but has been a primary source of its emotional character as well. According to Persian historian and archaeologist Arthur Pope, the supreme Iranian art, in the proper meaning of the word, has always been its architecture; the supremacy of architecture applies to both pre- and post-Islamic periods. Traditional Persian architecture has maintained a continuity that, although temporarily distracted by internal political conflicts or foreign invasion, nonetheless has achieved an unmistakable style. In this architecture, "there are no trivial buildings. In expressiveness and communicativity, most Persian buildings are lucid - eloquent; the combination of intensity and simplicity of form provides immediacy, while ornament and subtle proportions reward sustained observation." Overall, the traditional architecture of the Iranian lands throughout the ages can be categorized into the six following classes or styles: Zoroastrian: The Parsian style including: Pre-Parsian style e.g. Chogha Zanbil, Median style, Achaemenid style manifesting in construction of spectacular cities used for governance and inhabitation, temples made for worship and social gatherings, mausoleums erected in honor of fallen kings, The Parthian style includes designs from the following eras: Seleucid era e.g. Anahita Temple, Parthian era e.g. Hatra, the royal compounds at Nysa, Sassanid era e.g. Ghal'eh Dokhtar, the Taq-i Kisra, Darband.
Islamic: The Khorasani style, e.g. Jameh Mosque of Nain and Jameh Mosque of Isfahan, The Razi style which includes the methods and devices of the following periods: Samanid period, e.g. Samanid Mausoleum, Ziyarid period, e.g. Gonbad-e Qabus, Seljukid period, e.g. Kharraqan towers, The Azari style, e.g. Soltaniyeh, Arg-i Alishah, Jameh Mosque of Varamin, Goharshad Mosque, Bibi Khanum mosque in Samarqand, tomb of Abdas-Samad, Gur-e Amir, Jameh mosque of Yazd The Isfahani style spanning through the Safavid, Afsharid and Qajarid dynasties starting from the 16th century onward, e.g. Chehelsotoon, Ali Qapu, Agha Bozorg Mosque, Shah Mosque, Sheikh Lotf Allah Mosque in Naqsh-i Jahan Square. Available building materials dictate major forms in traditional Iranian architecture. Heavy clays available at various places throughout the plateau, have encouraged the development of the most primitive of all building techniques, molded mud, compressed as solidly as possible, allowed to dry; this technique, used in Iran from ancient times, has never been abandoned.
The abundance of heavy plastic earth, in conjunction with a tenacious lime mortar facilitated the development and use of brick. Iranian architecture makes use of abundant symbolic geometry, using pure forms such as circles and squares, plans are based on symmetrical layouts featuring rectangular courtyards and halls. Certain design elements of Persian architecture have persisted throughout the history of Iran; the most striking are a discerning use of simple and massive forms. The consistency of decorative preferences, the high-arched portal set within a recess, columns with bracket capitals, recurrent types of plan and elevation can be mentioned. Through the ages these elements have recurred in different types of buildings, constructed for various programs and under the patronage of a long succession of rulers; the columned porch, or talar, seen in the rock-cut tombs near Persepolis, reappear in Sassanid temples, in late Islamic times it was used as the portico of a palace or mosque, adapted to the architecture of roadside tea-houses.
The dome on four arches, so characteristic of Sassanid times, is a still to be found in many cemeteries and Imamzadehs across Iran today. The notion of earthly towers reaching up toward the sky to mingle with the divine towers of heaven las
Moroccan architecture dates from 110 BCE with the massive pisé buildings. The architecture has been influenced by Islamization during the Idrisid dynasty, Moorish exiles from Spain. Morocco is in Northern-Africa bordering the Atlantic; the country's diverse geography and the land's long history marked by successive waves of settlers and military encroachments are all reflected in Morocco's architecture. Morocco's first independent state called the Berber kingdom of Mauretania was ruled by the Berbers clan, it was first documented during 110 BC. During the time of the Berbers, the country has been through several sieges by a number of invaders; the Berbers ritual and beliefs still remained and became the country's cultural heritage including its antique architecture. The Berbers are known for their use of earth or mud brick called pisé. Many of the massive pisé buildings had defensive functions as main trading posts and ports or guard walls against pirates and rivals; this ancient building method prevails in all sizes of buildings.
Since pisé is a water- permeable material, the foundation is required to be rebuilt regularly. Moreover, Moroccan traditional architecture gained influences from neighboring countries and intruders; the conversion of the Berber tribes in Morocco to Islam by Idris I of Morocco influenced the overall architectural style of the country. The elegance of Islamic features is blended in and adapted into buildings and interior designs such as the use of tiling, geometric design and floral motifs. Which could be seen in mosques, plazas as well as homes; the materials chosen for the interiors of Moroccan classical architecture, are due in part to the necessity of cooling in the arid land climate of Morocco. Tiles – Zellige tiling wrongly labelled "mosaic", is used to decorate the surfaces of buildings and objects, principally interior walls and fountains. Modern use of zellige has extended the use to furniture and other interiors. Fountains – Before the conversion, water was an important part of Moroccan culture.
Thus, fountains representing paradise, could be found everywhere in order to serve everyone. Mosques – Following the introduction of Islam, mosques were built in Morocco with their distinct architectural features. Geometric Design and Floral Motifs Arabesque – Based on Islamic beliefs, avoiding the use of human or animal images is preferable resulting in the spread of floral motifs and geometric patterns; the motifs in Moroccan architectural decor are chiefly carved into stone and wood. Moroccan Islamic architecture is not confined to the country. For example, Sheikha Salama Mosque in the UAE city of Al Ain has two minarets which look Moroccan. Modern day Spain was a Moorish domain from the early 8th century to the late 15th century and was known as Al-Andalus 711 AD to 1492 AD. During the 11th century the berber dynasty of the Almohad Caliphate, ruled Morocco and the southern part of modern-day Spain the most famous of their remaining buildings are the Koutoubia Mosque in Marrakesh, the Giralda of Seville and the Hassan Tower, in Rabat, Morocco.
The Almoravid dynasty ruled the southern half of Spain through the 12th century. The Marinid dynasty from the 13th through the 15th century, rule both Moroccan and Southern Spain until the Reconquista with the fall of Granada in 1492 ending the Moorish era in Iberia. Moorish architecture therefore evolved into a distinct form; the elements of which are as follows Arches – Arches are common feature in Morocco, which can be divided into two types. The first arch is the horseshoe, clover shaped; the second is cusped like a rounded keyhole. These are called Moorish arches. Tiling – Overlapping roof tiling became popular after the influence of Spain. France occupied Morocco in 1912; as a result of the unorganized growth of real estate in the late 1800s to early 1900s, the French protector declared regulations for building standards which directly affected the architecture at that time, as follows: Buildings could not be higher than four stories. Land use regulation required twenty percent of a planned area to be gardens.
Balconies must not overlook neighboring residences. Roofs of all buildings should be flat; the building regulations maintained the country's preexisting architectural features and balanced the rapid urbanization. The Riad known as Dar is the Moroccan traditional house, which has two or more storeys around a courtyard. Villas are larger stand-alone housing in the urbanized area which do not need to follow traditional architectural style. Arches, most the horseshoe arch are used in every aspect of Moroccan housing whether it is doors, windows or niches. Domes are integrated with altars or commemorative monuments as well as modern villas; the interior doors of villas are oversized and decorative. In contrast small doors are used in dars. Doors are adorned with delicate metal work, carving or color. In contrast with doors, windows in Moroccan architecture are unremarkable, they are arched glass panes with fewer adornments compared to doors. Mashrabiya is an Islamic dowel work, made by carving large wood partitions in elaborate geometric patterns.
Its purpose is to conceal the women from the visitor’s prying eyes according to Islamic tradition. The fountain is a conspicuous feature in every house made of marble or cement, it is built in the heart of the courtyard, living room or g
A ceramic is a solid material comprising an inorganic compound of metal, non-metal or metalloid atoms held in ionic and covalent bonds. Common examples are earthenware and brick; the crystallinity of ceramic materials ranges from oriented to semi-crystalline and completely amorphous. Most fired ceramics are either vitrified or semi-vitrified as is the case with earthenware and porcelain. Varying crystallinity and electron composition in the ionic and covalent bonds cause most ceramic materials to be good thermal and electrical insulators. With such a large range of possible options for the composition/structure of a ceramic, the breadth of the subject is vast, identifiable attributes are difficult to specify for the group as a whole. General properties such as high melting temperature, high hardness, poor conductivity, high moduli of elasticity, chemical resistance and low ductility are the norm, with known exceptions to each of these rules. Many composites, such as fiberglass and carbon fiber, while containing ceramic materials, are not considered to be part of the ceramic family.
The earliest ceramics made by humans were pottery objects or figurines made from clay, either by itself or mixed with other materials like silica and sintered in fire. Ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through the use of glassy, amorphous ceramic coatings on top of the crystalline ceramic substrates. Ceramics now include domestic and building products, as well as a wide range of ceramic art. In the 20th century, new ceramic materials were developed for use in advanced ceramic engineering, such as in semiconductors; the word "ceramic" comes from the Greek word κεραμικός, "of pottery" or "for pottery", from κέραμος, "potter's clay, pottery". The earliest known mention of the root "ceram-" is the Mycenaean Greek ke-ra-me-we, "workers of ceramics", written in Linear B syllabic script; the word "ceramic" may be used as an adjective to describe a material, product or process, or it may be used as a noun, either singular, or, more as the plural noun "ceramics".
A ceramic material is an inorganic, non-metallic crystalline oxide, nitride or carbide material. Some elements, such as carbon or silicon, may be considered ceramics. Ceramic materials are brittle, strong in compression, weak in shearing and tension, they withstand chemical erosion that occurs in other materials subjected to acidic or caustic environments. Ceramics can withstand high temperatures, ranging from 1,000 °C to 1,600 °C. Glass is not considered a ceramic because of its amorphous character. However, glassmaking involves several steps of the ceramic process, its mechanical properties are similar to ceramic materials. Traditional ceramic raw materials include clay minerals such as kaolinite, whereas more recent materials include aluminium oxide, more known as alumina; the modern ceramic materials, which are classified as advanced ceramics, include silicon carbide and tungsten carbide. Both are valued for their abrasion resistance and hence find use in applications such as the wear plates of crushing equipment in mining operations.
Advanced ceramics are used in the medicine, electronics industries and body armor. Crystalline ceramic materials are not amenable to a great range of processing. Methods for dealing with them tend to fall into one of two categories – either make the ceramic in the desired shape, by reaction in situ, or by "forming" powders into the desired shape, sintering to form a solid body. Ceramic forming techniques include shaping by hand, slip casting, tape casting, injection molding, dry pressing, other variations. Noncrystalline ceramics, being glass, tend to be formed from melts; the glass is shaped when either molten, by casting, or when in a state of toffee-like viscosity, by methods such as blowing into a mold. If heat treatments cause this glass to become crystalline, the resulting material is known as a glass-ceramic used as cook-tops and as a glass composite material for nuclear waste disposal; the physical properties of any ceramic substance are a direct result of its crystalline structure and chemical composition.
Solid-state chemistry reveals the fundamental connection between microstructure and properties such as localized density variations, grain size distribution, type of porosity and second-phase content, which can all be correlated with ceramic properties such as mechanical strength σ by the Hall-Petch equation, toughness, dielectric constant, the optical properties exhibited by transparent materials. Ceramography is the art and science of preparation and evaluation of ceramic microstructures. Evaluation and characterization of ceramic microstructures is implemented on similar spatial scales to that used in the emerging field of nanotechnology: from tens of angstroms to tens of micrometers; this is somewhere between the minimum wavelength of visible light and the resolution limit of the naked eye. The microstructure includes most grains, secondary phases, grain boundaries, micro-
Umayyad architecture developed in the Umayyad Caliphate between 661 and 750 in its heartlands of Syria and Palestine. It drew extensively on the architecture of other Middle Eastern civilizations and that of the Byzantine Empire, but introduced innovations in decoration and new types of building such as mosques with mihrab's and minarets; the Umayyad caliphate was established in 661 after Ali, the son-in-law of Muhammad, was murdered in Kufa. Muawiyah I, governor of Syria, became the first Umayyad caliph; the Umayyads made Damascus their capital. Under the Umayyads the Arab empire continued to expand extending to Central Asia and the borders of India in the east, Yemen in the south, the Atlantic coast of what is now Morocco and the Iberian peninsula in the west; the Umayyads built new cities unfortified military camps that provided bases for further conquests. Wasit, Iraq was the most important of these, included a square Friday mosque with a hypostyle roof; the empire was secular and tolerant of existing customs in the conquered lands, creating resentment among those looking for a more theocratic state.
In 747 a revolution began in the east. By 750 the Umayyads had been overthrown by the Abbasids. A branch of the Umayyad dynasty continued to rule in Eberia until 1051. All monuments from the Umayyad period that have survived are in Syria and Palestine; the sanctuary of the Dome of the Rock in Jerusalem is the oldest surviving Islamic building. The Umayyads adopted the construction techniques of Byzantine architecture and Sasanian architecture, they re-used existing buildings. There was some innovation in types of building. Most buildings in Syria were of high quality ashlar masonry, using large tightly-joined blocks, sometimes with carving on the facade. Stone barrel vaults were only used to roof small spans. Wooden roofs were used with the wood in Syria brought from the forests of Lebanon; these roofs had shallow pitches and rested on wooden trusses. Wooden domes were constructed both in Jerusalem. Baked brick and mud brick were used in Mesopotamia, due to lack of stone. Where brick was used in Syria, the work was in the finer Mesopotamian style rather than the more crude Byzantine style.
The Umayyads used local architects. Some of their buildings cannot be distinguished from those of the previous regime. However, in many cases eastern and western elements were combined to give a distinctive new Islamic style. For example, the walls at Qasr Mshatta are built from cut stone in the Syrian manner, the vaults are Mesopotamian in design and Coptic and Byzantine elements appear in the decorative carving; the horseshoe arch appears for the first time in Umayyad architecture to evolve to its most advanced form in al-Andalus. Umayyad architecture is distinguished by the extent and variety of decoration, including mosaics, wall painting and carved reliefs with Islamic motifs; the Umayyads are known for some new and some adapted from earlier forts. The largest is Qasr al-Hayr al-Sharqi; the palaces were symbolically defended by walls and gates. In some cases the outside walls carried decorative friezes; the palaces would have a bath house, a mosque, a main castle. The entrance to the castle would be elaborate.
Towers along the walls would hold apartments with three or five rooms. These rooms were simple; the palaces had a second floor holding formal meeting rooms and official apartments. The fortress-like appearance was misleading, thus Qasr Kharana appears to have arrowslits. The fortress-like plan was derived from Roman forts built in Syria, construction followed earlier Syrian methods with some Byzantine and Mesopotamian elements; the baths derive from Roman models, but had smaller heated rooms and larger ornate rooms that would have been used for entertainment. The palaces had floor mosaics and frescoes or paintings on the walls, with designs that show both eastern and western influences. One fresco in the bath of Qasr Amra depicts six kings. Inscriptions below in Arabic and Greek identify the first four as the rulers of Byzantium, Spain and Abyssinia. Stucco sculptures were sometimes incorporated in the palace buildings. Qasr al-Hayr al-Sharqi is about 100 kilometres northeast of Palmyra on the main road from Aleppo to Iraq.
A large walled enclosure 7 by 4 kilometres was used to contain domestic animals. A walled madina, or city, contained an olive oil press and six large houses. Nearby there was some simpler houses. According to an inscription dated 728, the caliph provided significant funding for its development; the settlement was soon modified. The madina had four gates, one in each wall, but three were soon walled up; the basic layout was formal, but the buildings failed to comply with the plan. Most of the desert palaces were abandoned after the Umayyads fell from power, remain as ruins. Mosques were makeshift. In Iraq, they evolved from square prayer enclosures; the ruins of two large Umayyad mosques have been found in Iraq. One is 240 by the other 213 by 135 metres. Both had hypostyle designs, with roofs supported by elaborately designed columns. In Syria, the Umayyads preserved the overall concept of a court surrounded by porticos, with a deeper sanctuary, developed in Medina. Rather than make the sanctuary a hypostyle hall, as was done in Iraq, they divided it into three aisles