Chicago the City of Chicago, is the most populous city in Illinois, as well as the third most populous city in the United States. With an estimated population of 2,716,450, it is the most populous city in the Midwest. Chicago is the principal city of the Chicago metropolitan area referred to as Chicagoland, the county seat of Cook County, the second most populous county in the United States; the metropolitan area, at nearly 10 million people, is the third-largest in the United States, the fourth largest in North America and the third largest metropolitan area in the world by land area. Located on the shores of freshwater Lake Michigan, Chicago was incorporated as a city in 1837 near a portage between the Great Lakes and the Mississippi River watershed and grew in the mid-nineteenth century. After the Great Chicago Fire of 1871, which destroyed several square miles and left more than 100,000 homeless, the city made a concerted effort to rebuild; the construction boom accelerated population growth throughout the following decades, by 1900 Chicago was the fifth largest city in the world.
Chicago made noted contributions to urban planning and zoning standards, including new construction styles, the development of the City Beautiful Movement, the steel-framed skyscraper. Chicago is an international hub for finance, commerce, technology, telecommunications, transportation, it is the site of the creation of the first standardized futures contracts at the Chicago Board of Trade, which today is the largest and most diverse derivatives market gobally, generating 20% of all volume in commodities and financial futures. O'Hare International Airport is the one of the busiest airports in the world, the region has the largest number of U. S. highways and greatest amount of railroad freight. In 2012, Chicago was listed as an alpha global city by the Globalization and World Cities Research Network, it ranked seventh in the entire world in the 2017 Global Cities Index; the Chicago area has one of the highest gross domestic products in the world, generating $680 billion in 2017. In addition, the city has one of the world's most diversified and balanced economies, not being dependent on any one industry, with no single industry employing more than 14% of the workforce.
Chicago's 58 million domestic and international visitors in 2018, made it the second most visited city in the nation, behind New York City's approximate 65 million visitors. The city ranked first place in the 2018 Time Out City Life Index, a global quality of life survey of 15,000 people in 32 cities. Landmarks in the city include Millennium Park, Navy Pier, the Magnificent Mile, the Art Institute of Chicago, Museum Campus, the Willis Tower, Grant Park, the Museum of Science and Industry, Lincoln Park Zoo. Chicago's culture includes the visual arts, film, comedy and music jazz, soul, hip-hop and electronic dance music including house music. Of the area's many colleges and universities, the University of Chicago, Northwestern University, the University of Illinois at Chicago are classified as "highest research" doctoral universities. Chicago has professional sports teams in each of the major professional leagues, including two Major League Baseball teams; the name "Chicago" is derived from a French rendering of the indigenous Miami-Illinois word shikaakwa for a wild relative of the onion, known to botanists as Allium tricoccum and known more as ramps.
The first known reference to the site of the current city of Chicago as "Checagou" was by Robert de LaSalle around 1679 in a memoir. Henri Joutel, in his journal of 1688, noted that the eponymous wild "garlic" grew abundantly in the area. According to his diary of late September 1687:...when we arrived at the said place called "Chicagou" which, according to what we were able to learn of it, has taken this name because of the quantity of garlic which grows in the forests in this region. The city has had several nicknames throughout its history such as the Windy City, Chi-Town, Second City, the City of the Big Shoulders, which refers to the city's numerous skyscrapers and high-rises. In the mid-18th century, the area was inhabited by a Native American tribe known as the Potawatomi, who had taken the place of the Miami and Sauk and Fox peoples; the first known non-indigenous permanent settler in Chicago was Jean Baptiste Point du Sable. Du Sable arrived in the 1780s, he is known as the "Founder of Chicago".
In 1795, following the Northwest Indian War, an area, to be part of Chicago was turned over to the United States for a military post by native tribes in accordance with the Treaty of Greenville. In 1803, the United States Army built Fort Dearborn, destroyed in 1812 in the Battle of Fort Dearborn and rebuilt; the Ottawa and Potawatomi tribes had ceded additional land to the United States in the 1816 Treaty of St. Louis; the Potawatomi were forcibly removed from their land after the Treaty of Chicago in 1833. On August 12, 1833, the Town of Chicago was organized with a population of about 200. Within seven years it grew to more than 4,000 people. On June 15, 1835, the first public land sales began with Edmund Dick Taylor as U. S. Receiver of Public Monies; the City of Chicago was incorporated on Saturday, March 4, 1837, for several decades was the world's fastest-growing city. As the site of the Chicago Portage, the city became an important transportation hub between the eastern and western United States.
Chicago's first railway and Chicago Union Railroad, the Illi
The Queensboro Bridge known as the 59th Street Bridge – because its Manhattan end is located between 59th and 60th Streets – and titled the Ed Koch Queensboro Bridge, is a cantilever bridge over the East River in New York City, completed in 1909. It connects the neighborhood of Long Island City in the borough of Queens with the neighborhood of the Upper East Side Manhattan, passing over Roosevelt Island; the Queensboro Bridge carries New York State Route 25, which terminates at the west side of the bridge. The bridge once carried NY 25A as well; the western leg of the Queensboro Bridge is flanked on its northern side by the freestanding Roosevelt Island Tramway. The bridge was, for a long time called the Queensboro Bridge, but in March 2011, the bridge was renamed in honor of former New York City mayor Ed Koch. No tolls are charged for motor vehicles to use the bridge; the Queensboro Bridge is the first entry point into Manhattan in the course of the New York City Marathon and the last exit point out of Manhattan in the Five Boro Bike Tour.
The Queensboro Bridge is a two-level double cantilever bridge. It has one over the channel on each side of Roosevelt Island; the bridge does not have suspended spans, so the cantilever arm from each side reaches to the midpoint of the span. The lengths of its five spans and approaches are as follows: Manhattan to Roosevelt Island span length: 1,182 ft Roosevelt Island span length: 630 ft Roosevelt Island to Queens span length: 984 ft Side span lengths: 469 and 459 ft Total length between anchorages: 3,724 ft Total length including approaches: 7,449 ft Until it was surpassed by the Quebec Bridge in 1917, the span between Manhattan and Roosevelt Island was the longest cantilever span in North America; the upper level of the bridge has four lanes of automobile traffic, consisting of two roadways with two lanes in each directions. It provides a view of the New York skyline. Although the two upper level roadways both end at Thomson Avenue on the Queens side, they diverge in opposite directions on the Manhattan side.
The lanes used by westbound traffic, located on the northern side of the bridge, lead north to 62nd and 63rd Streets. On the other hand, the lanes used by eastbound traffic are located on the southern side of the bridge lead south to 57th and 58th Streets; the roadway to 57th and 58th Streets is used as a westbound high-occupancy vehicle lane during rush hours. The lower level has five vehicular lanes, the inner four for automobile traffic and the southern outer lane for automobile traffic as well, used for Queens-bound traffic; the North Outer Roadway was converted into a permanent pedestrian walk and bicycle path in September 2000. The Manhattan approach to the bridge is supported on a series of Guastavino tile vaults which formed the elegant ceiling of the former Food Emporium Bridge Market and the restaurant Guastavino's, located under the bridge; this open air promenade was known as Bridgemarket and was part of Hornbostel's attempt to make the bridge more hospitable in the city. Serious proposals for a bridge linking Manhattan to Long Island City were first made as early as 1838 and attempts to finance such a bridge were made by a private company beginning in 1867.
Its efforts never came to fruition and the company went bankrupt in the 1890s. Successful plans came about in 1903 – after the creation in 1898 of Greater New York City through the amalgamation of Manhattan, Queens, the Bronx and Staten Island – under the new city's Department of Bridges, led by Gustav Lindenthal, appointed to the new position of Commissioner of Bridges in 1902, in collaboration with Leffert L. Buck and Henry Hornbostel, designers of the Williamsburg Bridge. Construction soon began, but it would take until 1909 for the bridge to be completed due to delays from the collapse of an incomplete span during a windstorm, from labor unrest, which included an attempt to dynamite one span; the bridge opened for public use on March 1909, having cost about $18 million and 50 lives. There was a ten-cent toll to drive over the bridge; the bridge's ceremonial grand opening was held on June 12, 1909. At the time, it was the fourth longest bridge in the world; the grand opening included. The bridge was known as the Blackwell's Island Bridge, from an earlier name for Roosevelt Island.
The bridge's upper level contained two pedestrian walkways and two elevated railway tracks. Three lanes of roadway were installed on the south side of the upper level in 1931, replacing the former upper-level walkway. All service on the Second Avenue Elevated was discontinued in 1942. From 1955 to 1958, two additional lanes were built on the upper level; the upper-level ramps on the Queens end of the bridge were built during the same time. The lower deck hosted four motor traffic lanes, what is now the "outer roadway" and pedestrian walk were two trolley lanes. A trolley connected passengers from Queens and Manhattan to a stop in the middle of the bridge, where passengers could take an elevator or the stairs down to Roosevelt Island; the trolley operated from the bridge's opening until April 7, 1957. The trolley lanes and mid-bridge station, as well as the stairs, were removed in the 1950s – the trolley's last run was on April 7, 1957 – and for the next few decades the bridge carried 11 lanes of automobile traffic.
In 1930, an elevator was built on the bridge to transport cars and passengers to what was called Welfare Island, now Roos
Supreme Court of the United States
The Supreme Court of the United States is the highest court in the federal judiciary of the United States. Established pursuant to Article III of the U. S. Constitution in 1789, it has original jurisdiction over a narrow range of cases, including suits between two or more states and those involving ambassadors, it has ultimate appellate jurisdiction over all federal court and state court cases that involve a point of federal constitutional or statutory law. The Court has the power of judicial review, the ability to invalidate a statute for violating a provision of the Constitution or an executive act for being unlawful. However, it may act only within the context of a case in an area of law over which it has jurisdiction; the court may decide cases having political overtones, but it has ruled that it does not have power to decide nonjusticiable political questions. Each year it agrees to hear about one hundred to one hundred fifty of the more than seven thousand cases that it is asked to review.
According to federal statute, the court consists of the Chief Justice of the United States and eight associate justices, all of whom are nominated by the President and confirmed by the Senate. Once appointed, justices have lifetime tenure unless they resign, retire, or are removed from office; each justice has a single vote in deciding. When the chief justice is in the majority, he decides. In modern discourse, justices are categorized as having conservative, moderate, or liberal philosophies of law and of judicial interpretation. While a far greater number of cases in recent history have been decided unanimously, decisions in cases of the highest profile have come down to just one single vote, exemplifying the justices' alignment according to these categories; the Court meets in the Supreme Court Building in Washington, D. C, its law enforcement arm is the Supreme Court of the United States Police. It was while debating the division of powers between the legislative and executive departments that delegates to the 1787 Constitutional Convention established the parameters for the national judiciary.
Creating a "third branch" of government was a novel idea. Early on, some delegates argued that national laws could be enforced by state courts, while others, including James Madison, advocated for a national judicial authority consisting of various tribunals chosen by the national legislature, it was proposed that the judiciary should have a role in checking the executive power to veto or revise laws. In the end, the Framers compromised by sketching only a general outline of the judiciary, vesting federal judicial power in "one supreme Court, in such inferior Courts as the Congress may from time to time ordain and establish", they delineated neither the exact powers and prerogatives of the Supreme Court nor the organization of the Template:Judicial branch as a whole. The 1st United States Congress provided the detailed organization of a federal judiciary through the Judiciary Act of 1789; the Supreme Court, the country's highest judicial tribunal, was to sit in the nation's Capital and would be composed of a chief justice and five associate justices.
The act divided the country into judicial districts, which were in turn organized into circuits. Justices were required to "ride circuit" and hold circuit court twice a year in their assigned judicial district. After signing the act into law, President George Washington nominated the following people to serve on the court: John Jay for chief justice and John Rutledge, William Cushing, Robert H. Harrison, James Wilson, John Blair Jr. as associate justices. All six were confirmed by the Senate on September 26, 1789. Harrison, declined to serve. In his place, Washington nominated James Iredell; the Supreme Court held its inaugural session from February 2 through February 10, 1790, at the Royal Exchange in New York City the U. S. capital. A second session was held there in August 1790; the earliest sessions of the court were devoted to organizational proceedings, as the first cases did not reach it until 1791. When the national capital moved to Philadelphia in 1790, the Supreme Court did so as well.
After meeting at Independence Hall, the Court established its chambers at City Hall. Under Chief Justices Jay and Ellsworth, the Court heard few cases; as the Court had only six members, every decision that it made by a majority was made by two-thirds. However, Congress has always allowed less than the court's full membership to make decisions, starting with a quorum of four justices in 1789; the court lacked a home of its own and had little prestige, a situation not helped by the era's highest-profile case, Chisholm v. Georgia, reversed within two years by the adoption of the Eleventh Amendment; the court's power and prestige grew during the Marshall Court. Under Marshall, the court established the power of judicial review over acts of Congress, including specifying itself as the supreme expositor of the Constitution and making several important constitutional rulings that gave shape and substance to the balance of power between the federal government and states; the Marshall Court ended the practice of each justice issuin
Grand Central Terminal
Grand Central Terminal is a commuter rail terminal located at 42nd Street and Park Avenue in Midtown Manhattan, New York City. Grand Central is the southern terminus of the Metro-North Railroad's Harlem and New Haven Lines, serving the northern parts of the New York metropolitan area, it contains a connection to the New York City Subway at Grand Central–42nd Street. The terminal is the third-busiest train station in North America, after Toronto Union Station and New York Penn Station; the distinctive architecture and interior design of Grand Central Terminal's station house have earned it several landmark designations, including as a National Historic Landmark. Its Beaux-Arts design incorporates numerous works of art. Grand Central Terminal is one of the world's ten most visited tourist attractions, with 21.9 million visitors in 2013, excluding train and subway passengers. The terminal's main concourse is used as a meeting place, is featured in films and television. Grand Central Terminal contains a variety of stores and food vendors, including a food court on its lower-level concourse.
Grand Central Terminal was named for the New York Central Railroad. Opened in 1913, the terminal was built on the site of two named predecessor stations, the first of which dates to 1871. Grand Central Terminal served intercity trains until 1991, when Amtrak began routing its trains through nearby Penn Station; the East Side Access project, which will bring Long Island Rail Road service to a new station beneath the terminal, is expected to be completed in late 2022. Grand Central covers 48 acres and has 44 platforms, more than any other railroad station in the world, its platforms, all below ground, serve 26 on the lower. 43 tracks are in use for passenger service. Another eight tracks and four platforms are being built on two new levels deep underneath the existing station as part of East Side Access. Unlike most stations in the Metro-North system, Grand Central Terminal is owned by Midtown Trackage Ventures, a private company, rather than by the Metropolitan Transportation Authority, which operates Metro-North and most of its stations, including Grand Central.
Grand Central Terminal was named by and for the New York Central Railroad, which built the station and its two precursors on the site. It has "always been more colloquially and affectionately known as Grand Central Station", the name of its immediate precursor that operated from 1900 until 1910 and which shares its name with the nearby U. S. Post Office station at 450 Lexington Avenue and, with the Grand Central–42nd Street subway station next to the terminal. Grand Central Terminal serves some 67 million passengers a year, more than any other Metro-North station. At morning rush hour, a train arrives at the terminal every 58 seconds. Three of Metro-North's five main lines terminate at Grand Central: Harlem Line to Wassaic, New York Hudson Line to Poughkeepsie, New York New Haven Line to New Haven, Connecticut New Canaan Branch to New Canaan, Connecticut Danbury Branch to Danbury, Connecticut Waterbury Branch to Waterbury, ConnecticutThrough these lines, the terminal serves Metro-North commuters traveling to and from the Bronx in New York City.
The New York City Subway's adjacent Grand Central–42nd Street station serves these routes: 4, 5, 6, <6> trains, situated diagonally under the Pershing Square Building, 42nd Street, Grand Hyatt New York 7 and <7> trains, under 42nd Street between Park Avenue and west of Third Avenue S train, under 42nd Street between Madison Avenue and Vanderbilt AvenueThese MTA Regional Bus Operations buses stop near Grand Central: NYCT Bus: M1, M2, M3, M4 and Q32 local buses at Madison Avenue and Fifth Avenue X27, X28, X37, X38, SIM4C, SIM6, SIM8, SIM8X, SIM11, SIM22, SIM25, SIM26, SIM30, SIM31 and SIM33C express buses at Madison Avenue X27, X28, X37, X38, SIM4C, SIM8, SIM8X, SIM25, SIM31 and SIM33C express buses at Fifth Avenue M42 local bus at 42nd Street M101, M102 and M103 local buses at Third Avenue and Lexington Avenue X27, X28, X63, X64 and X68 express buses at Third Avenue SIM6, SIM11, SIM22 and SIM26 express buses at Lexington Avenue MTA Bus: BxM3, BxM4, BxM6, BxM7, BxM8, BxM9, BxM10, BxM18, BM1, BM2, BM3, BM4 and BM5 express buses at Madison Avenue and Fifth Avenue BxM1 express bus at Lexington Avenue BxM1, QM21, QM31, QM32, QM34, QM35, QM36, QM40, QM42 and QM44 express buses at Third Avenue Academy Bus: SIM23 and SIM24 express buses at Madison Avenue and Fifth Avenue The terminal and its predecessors were designed for intercity service, which operated from the first station building's completion in 1871 until Amtrak ceased operations in the terminal in 1991.
Through transfers, passengers could connect to all major lines in the United States, including the Canadian, the Empire Builder, the San Francisco Zephyr, the Southwest Limited, the Crescent, the Sunset Limited under Amtrak. Destinations included San Francisco, Los Angeles, New Orleans and Montreal. Another notable former train was New York Central's 20th Century Limited, a luxury service that oper
Nebraska is a state that lies in both the Great Plains and the Midwestern United States. It is bordered by South Dakota to the north, it is the only triply landlocked U. S. state. Nebraska's area is just over 77,220 square miles with a population of 1.9 million people. Its state capital is Lincoln, its largest city is Omaha, on the Missouri River. Indigenous peoples, including Omaha, Ponca, Pawnee and various branches of the Lakota tribes, lived in the region for thousands of years before European exploration; the state is crossed including that of the Lewis and Clark Expedition. Nebraska was admitted as the 37th state of the United States in 1867, it is the only state in the United States whose legislature is unicameral and nonpartisan. Nebraska is composed of two major land regions: the Great Plains; the Dissected Till Plains region consist of rolling hills and contains the state's largest cities and Lincoln. The Great Plains region, occupying most of western Nebraska, is characterized by treeless prairie, suitable for cattle-grazing.
Nebraska has two major climatic zones. The eastern half of the state has a humid continental climate; the western half of the state has a semi-arid climate. The state has wide variations between winter and summer temperatures, variations that decrease moving south in the state. Violent thunderstorms and tornadoes occur during spring and summer and sometimes in autumn. Chinook winds tend to warm the state in the winter and early spring. Nebraska's name is derived from transliteration of the archaic Otoe words Ñí Brásge, pronounced, or the Omaha Ní Btháska, meaning "flat water", after the Platte River that flows through the state. Indigenous peoples lived in the region of present-day Nebraska for thousands of years before European exploration; the historic tribes in the state included the Omaha, Ponca, Pawnee and various branches of the Lakota, some of which migrated from eastern areas into this region. When European exploration and settlement began, both Spain and France sought to control the region.
In the 1690s, Spain established trade connections with the Apaches, whose territory included western Nebraska. By 1703, France had developed a regular trade with the native peoples along the Missouri River in Nebraska, by 1719 had signed treaties with several of these peoples. After war broke out between the two countries, Spain dispatched an armed expedition to Nebraska under Lieutenant General Pedro de Villasur in 1720; the party was attacked and destroyed near present-day Columbus by a large force of Pawnees and Otoes, both allied to the French. The massacre ended Spanish exploration of the area for the remainder of the 18th century. In 1762, during the Seven Years' War, France ceded the Louisiana territory to Spain; this left Spain competing for dominance along the Mississippi. In response, Spain dispatched two trading expeditions up the Missouri in 1794 and 1795; that year, Mackay's party built a trading post, dubbed Fort Carlos IV, near present-day Homer. In 1819, the United States established Fort Atkinson as the first U.
S. Army post west of the Missouri River, just east of present-day Fort Calhoun; the army abandoned the fort in 1827. European-American settlement was scarce until the California Gold Rush. On May 30, 1854, the US Congress created the Kansas and the Nebraska territories, divided by the Parallel 40° North, under the Kansas–Nebraska Act; the Nebraska Territory included parts of the current states of Colorado, North Dakota, South Dakota and Montana. The territorial capital of Nebraska was Omaha. In the 1860s, after the U. S. government forced many of the Native American tribes to cede their lands and settle on reservations, it opened large tracts of land to agricultural development by Europeans and Americans. Under the Homestead Act, thousands of settlers migrated into Nebraska to claim free land granted by the federal government; because so few trees grew on the prairies, many of the first farming settlers built their homes of sod, as had Native Americans such as the Omaha. The first wave of settlement gave the territory a sufficient population to apply for statehood.
Nebraska became the 37th state on March 1, 1867, the capital was moved from Omaha to the center at Lancaster renamed Lincoln after the assassinated President of the United States, Abraham Lincoln. The battle of Massacre Canyon on August 5, 1873, was the last major battle between the Pawnee and the Sioux. During the 1870s to the 1880s, Nebraska experienced a large growth in population. Several factors contributed to attracting new residents; the first was. This helped settlers to learn the unfamiliar geography of the area; the second factor was the invention of several farming technologies. Agricultural inventions such as barbed wire, wind mills, the steel plow, combined with good weather, enabled settlers to use of Nebraska as prime farming land. By the 1880s, Nebraska's population
Mortar is a workable paste used to bind building blocks such as stones and concrete masonry units and seal the irregular gaps between them, sometimes add decorative colors or patterns in masonry walls. In its broadest sense mortar includes pitch and soft mud or clay, such as used between mud bricks. Mortar comes from Latin mortarium meaning crushed. Cement mortar becomes hard. Mortars are made from a mixture of sand, a binder, water; the most common binder since the early 20th century is Portland cement but the ancient binder lime mortar is still used in some new construction. Lime and gypsum in the form of plaster of Paris are used in the repair and repointing of buildings and structures because it is important the repair materials are similar to the original materials; the type and ratio of the repair mortar is determined by a mortar analysis. There are several types of cement additives; the first mortars were made of clay. Because of a lack of stone and an abundance of clay, Babylonian constructions were of baked brick, using lime or pitch for mortar.
According to Roman Ghirshman, the first evidence of humans using a form of mortar was at the Mehrgarh of Baluchistan in Pakistan, built of sun-dried bricks in 6500 BCE. The ancient sites of Harappan civilization of third millennium BCE are built with kiln-fired bricks and a gypsum mortar. Gypsum mortar called plaster of Paris, was used in the construction of the Egyptian pyramids and many other ancient structures, it is made from gypsum. It is therefore easier to make than lime mortar and sets up much faster which may be a reason it was used as the typical mortar in ancient, brick arch and vault construction. Gypsum mortar is not as durable as other mortars in damp conditions. In early Egyptian pyramids, which were constructed during the Old Kingdom, the limestone blocks were bound by mortar of mud and clay, or clay and sand. In Egyptian pyramids, the mortar was made of either gypsum or lime. Gypsum mortar was a mixture of plaster and sand and was quite soft. In the Indian subcontinent, multiple cement types have been observed in the sites of the Indus Valley Civilization, such as the Mohenjo-daro city-settlement that dates to earlier than 2600 BCE.
Gypsum cement, "light grey and contained sand, traces of calcium carbonate, a high percentage of lime" was used in the construction of wells, drains and on the exteriors of "important looking buildings." Bitumen mortar was used at a lower-frequency, including in the Great Bath at Mohenjo-daro. Building with concrete and mortar next appeared in Greece; the excavation of the underground aqueduct of Megara revealed that a reservoir was coated with a pozzolanic mortar 12 mm thick. This aqueduct dates back to c. 500 BCE. Pozzolanic mortar is a lime based mortar, but is made with an additive of volcanic ash that allows it to be hardened underwater; the Greeks obtained the volcanic ash from the Greek islands Thira and Nisiros, or from the Greek colony of Dicaearchia near Naples, Italy. The Romans improved the use and methods of making what became known as pozzolanic mortar and cement; the Romans used a mortar without pozzolana using crushed terra cotta, introducing aluminum oxide and silicon dioxide into the mix.
This mortar was not as strong as pozzolanic mortar, because it was denser, it better resisted penetration by water. Hydraulic mortar was not available in ancient China due to a lack of volcanic ash. Around 500 CE, sticky rice soup was mixed with slaked lime to make an inorganic−organic composite sticky rice mortar that had more strength and water resistance than lime mortar, it is not understood how the art of making hydraulic mortar and cement, perfected and in such widespread use by both the Greeks and Romans, was lost for two millennia. During the Middle Ages when the Gothic cathedrals were being built, the only active ingredient in the mortar was lime. Since cured lime mortar can be degraded by contact with water, many structures suffered from wind blown rain over the centuries. Ordinary Portland cement mortar known as OPC mortar or just cement mortar, is created by mixing powdered Ordinary Portland Cement, fine aggregate and water, it was invented in 1794 by Joseph Aspdin and patented on 18 December 1824 as a result of efforts to develop stronger mortars.
It was made popular during the late nineteenth century, had by 1930 became more popular than lime mortar as construction material. The advantages of Portland cement is that it sets hard and allowing a faster pace of construction. Furthermore, fewer skilled workers are required in building a structure with Portland cement; as a general rule, Portland cement should not be used for the repair or repointing of older buildings built in lime mortar, which require the flexibility and breathability of lime if they are to function correctly. In the United States and other countries, five standard types of mortar are used for both new construction and repair. Strengths of mortar change based on the ratio of cement and sand used in mortar; the ingredients and the mix ratio for each type of mortars are specified under the ASTM standards. These premixed mortar products are designated by one of the five letters, M, S, N, O, K. Type M mortar is the strongest, Type K the weakest; these type
A tile is a thin object square or rectangular in shape. Tile is a manufactured piece of hard-wearing material such as ceramic, metal, baked clay, or glass used for covering roofs, walls, or other objects such as tabletops. Alternatively, tile can sometimes refer to similar units made from lightweight materials such as perlite and mineral wool used for wall and ceiling applications. In another sense, a tile is a construction tile or similar object, such as rectangular counters used in playing games; the word is derived from the French word tuile, which is, in turn, from the Latin word tegula, meaning a roof tile composed of fired clay. Tiles are used to form wall and floor coverings, can range from simple square tiles to complex or mosaics. Tiles are most made of ceramic glazed for internal uses and unglazed for roofing, but other materials are commonly used, such as glass, cork and other composite materials, stone. Tiling stone is marble, granite or slate. Thinner tiles can be used on walls than on floors, which require more durable surfaces that will resist impacts.
Decorative tilework or tile art should be distinguished from mosaic, where forms are made of great numbers of tiny irregularly positioned tesserae, each of a single color of glass or sometimes ceramic or stone. The earliest evidence of glazed brick is the discovery of glazed bricks in the Elamite Temple at Chogha Zanbil, dated to the 13th century BC. Glazed and colored bricks were used to make low reliefs in Ancient Mesopotamia, most famously the Ishtar Gate of Babylon, now reconstructed in Berlin, with sections elsewhere. Mesopotamian craftsmen were imported for the palaces of the Persian Empire such as Persepolis; the use of sun-dried bricks or adobe was the main method of building in Mesopotamia where river mud was found in abundance along the Tigris and Euphrates. Here the scarcity of stone may have been an incentive to develop the technology of making kiln-fired bricks to use as an alternative. To strengthen walls made from sun-dried bricks, fired bricks began to be used as an outer protective skin for more important buildings like temples, city walls and gates.
Making fired. Fired bricks are solid masses of clay heated in kilns to temperatures of between 950° and 1,150°C, a well-made fired brick is an durable object. Like sun-dried bricks they were made in wooden molds but for bricks with relief decorations special molds had to be made. Rooms with tiled floors made of clay decorated with geometric circular patterns have been discovered from the ancient remains of Kalibangan and AhladinoTiling was used in the second century by the Sinhalese kings of ancient Sri Lanka, using smoothed and polished stone laid on floors and in swimming pools. Historians consider the techniques and tools for tiling as well advanced, evidenced by the fine workmanship and close fit of the tiles. Tiling from this period can be seen in Ruwanwelisaya and Kuttam Pokuna in the city of Anuradhapura; the Achaemenid Empire decorated buildings with glazed brick tiles, including Darius the Great's palace at Susa, buildings at Persepolis. The succeeding Sassanid Empire used tiles patterned with geometric designs, plants and human beings, glazed up to a centimeter thick.
Early Islamic mosaics in Iran consist of geometric decorations in mosques and mausoleums, made of glazed brick. Typical turquoise tiling becomes popular in 10th-11th century and is used for Kufic inscriptions on mosque walls. Seyyed Mosque in Isfahan, Dome of Maraqeh and the Jame Mosque of Gonabad are among the finest examples; the dome of Jame' Atiq Mosque of Qazvin is dated to this period. The golden age of Persian tilework began during the reign the Timurid Empire. In the moraq technique, single-color tiles were cut into small geometric pieces and assembled by pouring liquid plaster between them. After hardening, these panels were assembled on the walls of buildings, but the mosaic was not limited to flat areas. Tiles were used to cover both the exterior surfaces of domes. Prominent Timurid examples of this technique include the Jame Mosque of Yazd, Goharshad Mosque, the Madrassa of Khan in Shiraz, the Molana Mosque. Other important tile techniques of this time include girih tiles, with their characteristic white girih, or straps.
Mihrabs, being the focal points of mosques, were the places where most sophisticated tilework was placed. The 14th-century mihrab at Madrasa Imami in Isfahan is an outstanding example of aesthetic union between the Islamic calligrapher's art and abstract ornament; the pointed arch, framing the mihrab's niche, bears an inscription in Kufic script used in 9th-century Qur'an. One of the best known architectural masterpieces of Iran is the Shah Mosque in Isfahan, from the 17th century, its dome is a prime example of tile mosaic and its winter praying hall houses one of the finest ensembles of cuerda seca tiles in the world. A wide variety of tiles had to be manufactured in order to cover complex forms of the hall with consistent mosaic patterns; the result was a technological triumph as well as a dazzling display of abstract ornament. During the Safavid period, mosaic ornaments were replaced by a haft rang technique. Pictures were painted on plain rectangle tiles and fired afterwards. Besides economic reasons, the seven colors method gave more freedom to artists and was less time-consuming.
It was popular until the Qajar period, when the palette of colors was extended by orange. The seven colors of Haft Rang tiles were black, ultramarine