A cement is a binder, a substance used for construction that sets and adheres to other materials to bind them together. Cement is used on its own, but rather to bind sand and gravel together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Cement is the most used material in existence and is only behind water as the planet's most-consumed resource. Cements used in construction are inorganic lime or calcium silicate based, can be characterized as either hydraulic or non-hydraulic, depending on the ability of the cement to set in the presence of water. Non-hydraulic cement does not set under water. Rather, it sets as it reacts with carbon dioxide in the air, it is resistant to attack by chemicals after setting. Hydraulic cements set and become adhesive due to a chemical reaction between the dry ingredients and water; the chemical reaction results in mineral hydrates that are not water-soluble and so are quite durable in water and safe from chemical attack.
This allows setting in wet conditions or under water and further protects the hardened material from chemical attack. The chemical process for hydraulic cement found by ancient Romans used volcanic ash with added lime; the word "cement" can be traced back to the Roman term opus caementicium, used to describe masonry resembling modern concrete, made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick supplements that were added to the burnt lime, to obtain a hydraulic binder, were referred to as cementum, cimentum, cäment, cement. In modern times, organic polymers are sometimes used as cements in concrete. Non-hydraulic cement, such as slaked lime, hardens by carbonation in the presence of carbon dioxide, present in the air. First calcium oxide is produced from calcium carbonate by calcination at temperatures above 825 °C for about 10 hours at atmospheric pressure: CaCO3 → CaO + CO2The calcium oxide is spent mixing it with water to make slaked lime: CaO + H2O → Ca2Once the excess water is evaporated, the carbonation starts: Ca2 + CO2 → CaCO3 + H2OThis reaction takes time, because the partial pressure of carbon dioxide in the air is low.
The carbonation reaction requires that the dry cement be exposed to air, so the slaked lime is a non-hydraulic cement and cannot be used under water. This process is called the lime cycle. Conversely, hydraulic cement hardens by hydration. Hydraulic cements are made of a mixture of silicates and oxides, the four main components being: Belite; the silicates are responsible for the cement's mechanical properties—the tricalcium aluminate and brownmillerite are essential for formation of the liquid phase during the kiln sintering. The chemistry of these reactions is not clear and is still the object of research; the earliest known occurrence of cement is from twelve million years ago. A deposit of cement was formed after an occurrence of oil shale located adjacent to a bed of limestone burned due to natural causes; these ancient deposits were investigated in the 1970s. Cement, chemically speaking, is a product that includes lime as the primary curing ingredient, but is far from the first material used for cementation.
The Babylonians and Assyrians used bitumen to bind together burnt alabaster slabs. In Egypt stone blocks were cemented together with a mortar made of sand and burnt gypsum, which contained calcium carbonate. Lime was used by the ancient Greeks. There is evidence that the Minoans of Crete used crushed potshards as an artificial pozzolan for hydraulic cement. Nobody knows who first discovered that a combination of hydrated non-hydraulic lime and a pozzolan produces a hydraulic mixture —but such concrete was used by the Ancient Macedonians, three centuries on a large scale by Roman engineers. There is... a kind of powder. It is found in the neighborhood of Baiae and in the country belonging to the towns round about Mt. Vesuvius; this substance when mixed with lime and rubble not only lends strength to buildings of other kinds, but when piers of it are constructed in the sea, they set hard under water. The Greeks used volcanic tuff from the island of Thera as their pozzolan and the Romans used crushed volcanic ash with lime.
This mixture could set under water. The material was called pozzolana from the town of Pozzuoli, west of Naples where volcanic ash was extracted. In the absence of pozzolanic ash, the Romans used powdered brick or pottery as a substitute and they may have used crushed tiles for this purpose before discovering natural sources near Rome; the huge dome of the Pantheon in Rome and the massive Baths of Caracalla are examples of ancient structures made from these concretes, many of which still stand. The vast system of Roman aqueducts made extensive use of hydraulic cement. Roman concrete was used on the outside of buildings; the normal technique was to use brick facing material as the formwork for an infill of mortar mixed with an aggregate of broken pieces of stone, potsherds, recycled chunks of concrete, or other building ru
Louisiana Purchase Exposition
The Louisiana Purchase Exposition, informally known as the St. Louis World's Fair, was an international exposition held in St. Louis, United States, from April 30 to December 1, 1904. Local and federal funds totaling $15 million were used to finance the event. More than 60 countries and 43 of the 45 American states maintained exhibition spaces at the fair, attended by nearly 19.7 million people. Historians emphasize the prominence of themes of race and empire, the fair's long-lasting impact on intellectuals in the fields of history, art history and anthropology. From the point of view of the memory of the average person who attended the fair, it promoted entertainment, consumer goods and popular culture. In 1904, St. Louis hosted a World's Fair to celebrate the centennial of the 1803 Louisiana Purchase; the idea for such a commemorative event seems to have emerged early in 1898, with Kansas City and St. Louis presented as potential hosts for a fair based on their central location within the territory encompassed by the 1803 land annexation.
The exhibition was grand in scale and lengthy in preparation, with an initial $5 million committed by the city of St. Louis through the sale of city bonds was authorized by the Missouri state legislature in April 1899. An additional $5 million was generated through private donations by interested citizens and businesses from around Missouri, a fundraising target reached in January 1901; the final installment of $5 million of the exposition's $15 million capitalization came in the form of earmarked funds that were part of a congressional appropriations bill passed at the end of May 1900. The fundraising mission was aided by the active support of President of the United States William McKinley, won by organizers in a February 1899 White House visit. While conceived as a centennial celebration to be held in 1903, the actual opening of the St. Louis exposition was delayed until April 30, 1904, to allow for full-scale participation by more states and foreign countries; the exposition remained in operation from its opening until December 1, 1904.
During the year of the fair, the Louisiana Purchase Exposition supplanted the annual St. Louis Exposition of agricultural and scientific exhibitions, held in the city since the 1880s; the fair's 1,200-acre site, designed by George Kessler, was located at the present-day grounds of Forest Park and on the campus of Washington University, was the largest fair to date. There were over 1,500 buildings, connected by some 75 miles of walkways, it was said to be impossible to give a hurried glance at everything in less than a week. The Palace of Agriculture alone covered some 20 acres. Exhibits were staged by 50 foreign nations, the United States government, 43 of the then-45 U. S. states. These featured industries, private organizations and corporations, theater troupes, music schools. There were over 50 concession-type amusements found on "The Pike". Over 19 million individuals were in attendance at the fair. In conjunction with the Exposition the U. S. Post Office issued a series of five commemorative stamps celebrating the 100th anniversary of the Louisiana Purchase.
The 1-cent value portrayed Robert Livingston, the ambassador who negotiated the purchase with France, the 2-cent value depicts Thomas Jefferson, who executed the purchase, the 3-cent honors James Monroe, who participated in negotiations with the French, the 5-cent memorializes William McKinley, involved with early plans for the Exposition and the 10-cent presents a map of the Louisiana Purchase. Louisiana Purchase Commemoratives Kessler, who designed many urban parks in Texas and the Midwest, created the master design for the Fair. A popular myth says that Frederick Law Olmsted, who had died the year before the Fair, designed the park and fair grounds. There are several reasons for this confusion. First, Kessler in his twenties had worked for Olmsted as a Central Park gardener. Second, Olmsted was involved with Forest Park in New York. Third, Olmsted had planned the renovations in 1897 to the Missouri Botanical Garden several blocks to the southeast of the park. Olmsted's sons advised Washington University on integrating the campus with the park across the street.
In 1901 the Louisiana Purchase Exposition Corporation selected prominent St. Louis architect Isaac S. Taylor as the Chairman of the Architectural Commission and Director of Works for the fair, supervising the overall design and construction. Taylor appointed Emmanuel Louis Masqueray to be his Chief of Design. In the position for three years, Masqueray designed the following Fair buildings: Palace of Agriculture, the Cascades and Colonnades, Palace of Forestry and Game, Palace of Horticulture and Palace of Transportation, all of which were emulated in civic projects across the United States as part of the City Beautiful movement. Masqueray resigned shortly after the Fair opened in 1904, having been invited by Archbishop John Ireland of St. Paul, Minnesota to design a new cathedral for the city. Paul J. Pelz was architect for the Palace of Machinery. According to a claim in a 1923 edition of The Colored Citizen of Pensacola, the majority of work in building the fair was done by African Americans, including all the engineering calculations for the layout of the park.
Many African Americans were not credited. Florence Hayward, a successful freelance writer in St. Lo
New York (state)
New York is a state in the Northeastern United States. New York was one of the original thirteen colonies. With an estimated 19.54 million residents in 2018, it is the fourth most populous state. To distinguish the state from the city with the same name, it is sometimes called New York State; the state's most populous city, New York City, makes up over 40% of the state's population. Two-thirds of the state's population lives in the New York metropolitan area, nearly 40% lives on Long Island; the state and city were both named for the 17th century Duke of York, the future King James II of England. With an estimated population of 8.62 million in 2017, New York City is the most populous city in the United States and the premier gateway for legal immigration to the United States. The New York metropolitan area is one of the most populous in the world. New York City is a global city, home to the United Nations Headquarters and has been described as the cultural and media capital of the world, as well as the world's most economically powerful city.
The next four most populous cities in the state are Buffalo, Rochester and Syracuse, while the state capital is Albany. The 27th largest U. S. state in land area, New York has a diverse geography. The state is bordered by New Jersey and Pennsylvania to the south and Connecticut and Vermont to the east; the state has a maritime border with Rhode Island, east of Long Island, as well as an international border with the Canadian provinces of Quebec to the north and Ontario to the northwest. The southern part of the state is in the Atlantic coastal plain and includes Long Island and several smaller associated islands, as well as New York City and the lower Hudson River Valley; the large Upstate New York region comprises several ranges of the wider Appalachian Mountains, the Adirondack Mountains in the Northeastern lobe of the state. Two major river valleys – the north-south Hudson River Valley and the east-west Mohawk River Valley – bisect these more mountainous regions. Western New York is considered part of the Great Lakes region and borders Lake Ontario, Lake Erie, Niagara Falls.
The central part of the state is dominated by the Finger Lakes, a popular vacation and tourist destination. New York had been inhabited by tribes of Algonquian and Iroquoian-speaking Native Americans for several hundred years by the time the earliest Europeans came to New York. French colonists and Jesuit missionaries arrived southward from Montreal for trade and proselytizing. In 1609, the region was visited by Henry Hudson sailing for the Dutch East India Company; the Dutch built Fort Nassau in 1614 at the confluence of the Hudson and Mohawk rivers, where the present-day capital of Albany developed. The Dutch soon settled New Amsterdam and parts of the Hudson Valley, establishing the multicultural colony of New Netherland, a center of trade and immigration. England seized the colony from the Dutch in 1664. During the American Revolutionary War, a group of colonists of the Province of New York attempted to take control of the British colony and succeeded in establishing independence. In the 19th century, New York's development of access to the interior beginning with the Erie Canal, gave it incomparable advantages over other regions of the U.
S. built its political and cultural ascendancy. Many landmarks in New York are well known, including four of the world's ten most-visited tourist attractions in 2013: Times Square, Central Park, Niagara Falls, Grand Central Terminal. New York is home to the Statue of Liberty, a symbol of the United States and its ideals of freedom and opportunity. In the 21st century, New York has emerged as a global node of creativity and entrepreneurship, social tolerance, environmental sustainability. New York's higher education network comprises 200 colleges and universities, including Columbia University, Cornell University, New York University, the United States Military Academy, the United States Merchant Marine Academy, University of Rochester, Rensselaer Polytechnic Institute, Rockefeller University, which have been ranked among the top 40 in the nation and world; the tribes in what is now New York were predominantly Algonquian. Long Island was divided in half between the Wampanoag and Lenape; the Lenape controlled most of the region surrounding New York Harbor.
North of the Lenape was the Mohicans. Starting north of them, from east to west, were three Iroquoian nations: the Mohawk, the original Iroquois and the Petun. South of them, divided along Appalachia, were the Susquehannock and the Erie. Many of the Wampanoag and Mohican peoples were caught up in King Philip's War, a joint effort of many New England tribes to push Europeans off their land. After the death of their leader, Chief Philip Metacomet, most of those peoples fled inland, splitting into the Abenaki and the Schaghticoke. Many of the Mohicans remained in the region until the 1800s, however, a small group known as the Ouabano migrated southwest into West Virginia at an earlier time, they may have merged with the Shawnee. The Mohawk and Susquehannock were the most militaristic. Trying to corner trade with the Europeans, they targeted other tribes; the Mohawk were known for refusing white settlement on their land and banishing any of their people who converted to Christianity. They posed a major threat to the Abenaki and Mohicans, while the Susquehannock conquered the Lenape in the 1600s.
The most devastating event of the century, was the Beaver Wars. From 1640–1680, Iroquoian peoples waged campaigns which extended from modern-day Michigan to Virginia against Algonquian and Siouan tribes, as well as each other; the ai
Talc is a clay mineral composed of hydrated magnesium silicate with the chemical formula Mg3Si4O102. Talc in powdered form in combination with corn starch, is a used substance known as baby powder; this mineral is used as a thickening agent and lubricant, is an ingredient in ceramics and roofing material, is one of the main ingredients in many cosmetic products. It occurs as foliated to fibrous masses, in an exceptionally rare crystal form, it has a perfect basal cleavage, uneven flat fracture and it is foliated with a two dimensional platy form. The Mohs scale of mineral hardness is based on scratch hardness comparison, ranging from 1-10, a value of 10 being the hardest of minerals. Talc is the defining value 1 therefore the softest of minerals. Any mineral below a value of 2 on Mohs scale of mineral hardness can be scratched by a fingernail; when scraped on a streak plate it produces a white streak, though this indicator is of little importance because most silicate minerals produce a white streak.
Talc is translucent to opaque with colors ranging from whitish grey to green with a vitreous and pearly luster. Talc is not soluble in water, but is soluble in dilute mineral acids. Soapstone is a well known metamorphic rock composed predominantly of talc; the word "talc" derives from Medieval Latin talcum, which in turn originates from Arabic: طلق ṭalq which, derives from Persian: تالک tālk. In ancient times, the word was used for various related minerals, including talc and selenite. Talc is a mineral that results from the metamorphism of magnesian minerals such as serpentine, pyroxene and olivine, in the presence of carbon dioxide and water; this is known as "talc carbonation" or "steatization" and produces a suite of rocks known as talc carbonates. Talc is formed by hydration and carbonation by this reaction: serpentine2 Mg3Si2O54 + carbon dioxide3CO2 → talcMg3Si4O102 + magnesite3 MgCO3 + water3 H2OTalc can be formed via a reaction between dolomite and silica, typical of skarnification of dolomites by silica-flooding in contact metamorphic aureoles: dolomite3 CaMg2 + silica4 SiO2 + waterH2O → talcMg3Si4O102 + calcite3 CaCO3 + carbon dioxide3 CO2Talc can be formed from magnesian chlorite and quartz in blueschist and eclogite metamorphism by the following metamorphic reaction: chlorite + quartz → kyanite + talc + waterIn this reaction, the ratio of talc and kyanite depends on aluminium content, with more aluminous rocks favoring production of kyanite.
This is associated with high-pressure, low-temperature minerals such as phengite and glaucophane within the lower blueschist facies. Such rocks are white and fibrous, are known as whiteschist. Talc is a trioctahedral layered mineral. Talc is a common metamorphic mineral in metamorphic belts that contain ultramafic rocks, such as soapstone, within whiteschist and blueschist metamorphic terranes. Prime examples of whiteschists include the Franciscan Metamorphic Belt of the western United States, the western European Alps in Italy, certain areas of the Musgrave Block, some collisional orogens such as the Himalayas, which stretch along Pakistan, India and Bhutan. Talc carbonate ultramafics are typical of many areas of the Archaean cratons, notably the komatiite belts of the Yilgarn Craton in Western Australia. Talc-carbonate ultramafics are known from the Lachlan Fold Belt, eastern Australia, from Brazil, the Guiana Shield, from the ophiolite belts of Turkey and the Middle East. China is the key world talc and steatite producing country with an output of about 2.2M tonnes, which accounts for 30% of total global output.
The other major producers are Brazil, the U. S. France, Italy, Russia and Austria. Notable economic talc occurrences include the Mount Seabrook talc mine, Western Australia, formed upon a polydeformed, layered ultramafic intrusion; the France-based Luzenac Group is the world's largest supplier of mined talc. Its largest talc mine at Trimouns near Luzenac in southern France produces 400,000 tonnes of talc per year. Extraction in disputed areas of Nangarhar province, has led the international monitoring group Global Witness to declare talc a conflict mineral, as the profits are used to fund armed confrontation between the Taliban and Islamic State. Talc is used in many industries, including paper making, plastic and coatings, food, electric cable, pharmaceuticals and ceramics. A coarse grayish-green high-talc rock is soapstone or steatite, used for stoves, electrical switchboards, etc, it is used for surfaces of laboratory table tops and electrical switchboards because of its resistance to heat and acids.
In finely ground form, talc finds use as a cosmetic, as a lubricant, as a filler in paper manufacture. It is used to coat the insides of inner tubes and rubber gloves during manufacture to keep the surfaces from sticking. Talcum powder, with heavy refinement, has been used in baby powder, an astringent powder used to prevent diaper rash; the American Academy of Pediatrics recommends that parents not use baby powder because it poses a risk of respiratory problems, including breathing trouble and serious lung damage if the baby inhales it. The small size of the particles makes it difficult to keep them out of the air while applying the powder. Zinc oxide-based ointments are a much safer alternative, it is often used in basketball to keep a player's hands dry. Most tailor's chalk, or French chalk, is talc, as is the chalk used for welding or metalworki
Chalk is a soft, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO3, it forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells shed from micro-organisms called coccolithophores. Flint is common as bands parallel to the bedding or as nodules embedded in chalk, it is derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is deposited around larger fossils such as Echinoidea which may be silicified. Chalk as seen in Cretaceous deposits of Western Europe is unusual among sedimentary limestones in the thickness of the beds. Most cliffs of chalk have few obvious bedding planes unlike most thick sequences of limestone such as the Carboniferous Limestone or the Jurassic oolitic limestones; this indicates stable conditions over tens of millions of years. Chalk has greater resistance to weathering and slumping than the clays with which it is associated, thus forming tall, steep cliffs where chalk ridges meet the sea.
Chalk hills, known as chalk downland form where bands of chalk reach the surface at an angle, so forming a scarp slope. Because chalk is well jointed it can hold a large volume of ground water, providing a natural reservoir that releases water through dry seasons. Chalk is mined from chalk deposits both above underground. Chalk mining boomed during the Industrial Revolution, due to the need for chalk products such as quicklime and bricks; some abandoned chalk mines remain tourist destinations due to their massive expanse and natural beauty. The Chalk Group is a European stratigraphic unit, it forms the famous White Cliffs of Dover in Kent, England, as well as their counterparts of the Cap Blanc Nez on the other side of the Dover Strait. The Champagne region of France is underlain by chalk deposits, which contain artificial caves used for wine storage; some of the highest chalk cliffs in the world occur at Jasmund National Park in Germany and at Møns Klint in Denmark – both once formed a single island.
Ninety million years ago what is now the chalk downland of Northern Europe was ooze accumulating at the bottom of a great sea. Chalk was one of the earliest rocks made up of microscopic particles to be studied under the microscope, when it was found to be composed entirely of coccoliths, their shells were made of calcite extracted from the rich seawater. As they died, a substantial layer built up over millions of years and, through the weight of overlying sediments became consolidated into rock. Earth movements related to the formation of the Alps raised these former sea-floor deposits above sea level; the chemical composition of chalk is calcium carbonate, with minor amounts of clay. It is formed in the sea by sub-microscopic plankton, which fall to the sea floor and are consolidated and compressed during diagenesis into chalk rock. Most people first encounter the word "chalk" in school where it refers to blackboard chalk, made of mineral chalk, since it crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be erased.
Blackboard chalk manufacture now may use mineral chalk, other mineral sources of calcium carbonate, or the mineral gypsum. While gypsum-based blackboard chalk is the lowest cost to produce, thus used in the developing world, calcium-based chalk can be made where the crumbling particles are larger and thus produce less dust, is marketed as "dustless chalk". Colored chalks, pastel chalks, sidewalk chalk, used to draw on sidewalks and driveways, are made of gypsum. Chalk is a source of quicklime by thermal decomposition, or slaked lime following quenching of quicklime with water. In southeast England, deneholes are a notable example of ancient chalk pits; such bell pits may mark the sites of ancient flint mines, where the prime object was to remove flint nodules for stone tool manufacture. The surface remains at Cissbury are one such example, but the most famous is the extensive complex at Grimes Graves in Norfolk. Woodworking joints may be fitted by chalking one of the mating surfaces. A trial fit will leave a chalk mark on the high spots of the corresponding surface.
Chalk transferring to cover the complete surface indicates a good fit. Builder's putty mainly contains chalk as a filler in linseed oil. Chalk may be used for its properties as a base. In agriculture, chalk is used for raising pH in soils with high acidity; the most common forms are CaCO3 and CaO. Small doses of chalk can be used as an antacid. Additionally, the small particles of chalk make it a substance ideal for polishing. For example, toothpaste contains small amounts of chalk, which serves as a mild abrasive. Polishing chalk is chalk prepared with a controlled grain size, for fine polishing of metals. Chalk can be used as fingerprint powder. Several traditional uses of chalk have been replaced by other substances, although the word "chalk" is still applied to the usual replacements. Tailor's chalk is traditionally a hard chalk used to make temporary markings on cloth by tailors, it is now made of talc. Chalk was traditionally used in recreation. In field sports, such as tennis played on grass, powdered chalk was used to mark the boundary lines of the playing field or court.
If a ball hits the line, a cloud of chalk or p
Crayola LLC Binney & Smith, is an American handicraft company, specializing in artists' supplies. It is best known for its crayons; the company is based in Forks Township, Northampton County, Pennsylvania, USA. Since 1984, it has been a wholly owned subsidiary of Hallmark Cards. An industrial pigment supply company, Crayola soon shifted its focus to art products for home and school use, beginning with chalk crayons, followed by colored pencils, paints, modeling clay, other related goods. All Crayola-branded products are marketed as safe for use by children. Most Crayola crayons are manufactured in the United States; the company produces Silly Putty and a line of professional art products under the Portfolio Series brand. Crayola, LLC claims the Crayola brand has 99% name recognition in U. S. consumer households, says its products are marketed and sold in over 80 countries. The company was founded as Binney and Smith by cousins Edwin Binney and C. Harold Smith in New York City in 1885. Initial products were colorants for industrial use, including red iron oxide pigments used in barn paint and carbon black chemicals used for making tires black and extending their useful lifespan.
Binney & Smith's new process of creating inexpensive black colorants was entered into the chemistry industries competition at the 1900 Paris Exposition under the title "carbon gas blacks, lamp or oil blacks,'Peerless' black" and earned the company a gold medal award in chemical and pharmaceutical arts. In 1900, the company added production of slate school pencils. Binney's experimentation with industrial materials, including slate waste and talc, led to the invention of the first dustless white chalk, for which the company won a gold medal at the 1904 St. Louis World's Fair. Formed as a partnership, Binney & Smith incorporated in 1902, in that year Binney & Smith developed and introduced the Staonal marking crayon. Edwin Binney, working with his wife, Alice Stead Binney, developed his own famous product line of wax crayons beginning on 10 June 1903, which it sold under the brand name Crayola; the Crayola name was coined by Alice Binney, a former schoolteacher. It comes from craie and ola for "oleaginous" or "oily."
The suffix "-ola" was popular in commercial use at the time, lending itself to products such as granola, Victrola and Mazola. Crayola introduced its crayons not with a full product line. By 1905, the line had expanded to offering 18 different-sized crayon boxes with five different-sized crayons, only two of which survive today—the "standard size" and the "large size"; the product line offered crayon boxes containing 6, 7, 8, 12, 14, 16, 18, 24, 28, or 30 different color crayons. Some of these boxes were targeted for artists and contained crayons with no wrappers, while others had a color number printed on the wrapper that corresponded to a number on a list of color names printed inside the box lid, but some boxes contained crayons with their color names printed on their wrappers; the Rubens Crayola line, started in 1903, was directly targeted at artists and designed to compete with the Raphael brand of crayons from Europe. The crayon boxes sold from five cents for a No.6 Rubens box containing six different-colored crayons to $1.50 for the No. 500 Rubens Special Artists and Designers Crayon box containing 24 different-colored, larger crayons.
In April 1904 at the St. Louis World's Fair, Binney & Smith won the Gold Medal for their An-Du-Septic dustless chalk. Subsequently, Crayola used the opportunity to develop a new packaging strategy by emphasizing their gold medal on the front of many of their products and crayon boxes; this strategy turned out to be so successful and recognizable to their brand that they phased out nearly all of their other Crayola line box designs to adapt to the gold medal format, which appeared on their packaging for the next 50-plus years. In 1905, the prototype offering of their new No. 8 crayon box featured a copy from the side of the medal with an eagle on it. This was changed to the other side of the medal with the 1904 date on it in Roman numerals. Binney & Smith purchased the Munsell Color Company crayon product line in 1926, inherited 22 new colors, 11 in the maximum and 11 in the middle hue ranges, they retained the Munsell name on products such as “Munsell-Crayola” and “Munsell-Perma” until 1934, incorporated their colors into their own Crayola Gold Medal line of boxes.
In 1939, Crayola, by combining its existing crayon colors with the Munsell colors, introduced its largest color assortment product to date. In 1949, Crayola introduced the "Crayola No. 48" containing 48 color crayons in a non-peggable floor box. Further expansion took place in 1958 with the introduction of the 64-color pack that included the company's first crayon sharpener built into the box; the 64-color box was called "a watershed" moment in the history of the Crayola crayon by Smithsonian National Museum of American History curator David Shayt. The corporation became a publicly traded company under the symbol BYS on the American Stock Exchange in 1963, moved to the New York Stock Exchange under the same symbol in 1978. In 1977, Binney & Smith acquired the rights to a stretchy bouncy toy. Crayola markers were introduced in 1978 to coincide with the 75th anniversary of Crayola crayons. In 1984, the company was ac
A tire or tyre is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface traveled over. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, which provide a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, designed to match the weight of the vehicle with the bearing strength of the surface that it rolls over by providing a bearing pressure that will not deform the surface excessively; the materials of modern pneumatic tires are synthetic rubber, natural rubber and wire, along with carbon black and other chemical compounds. They consist of a body; the tread provides traction. Before rubber was developed, the first versions of tires were bands of metal fitted around wooden wheels to prevent wear and tear. Early rubber tires were solid. Pneumatic tires are used on many types of vehicles, including cars, motorcycles, trucks, heavy equipment, aircraft.
Metal tires are still used on locomotives and railcars, solid rubber tires are still used in various non-automotive applications, such as some casters, carts and wheelbarrows. The word tire is a short form of attire, from the idea; the spelling tyre does not appear until the 1840s when the English began shrink fitting railway car wheels with malleable iron. Traditional publishers continued using tire; the Times newspaper in Britain was still using tire as late as 1905. The spelling tyre began to be used in the 19th century for pneumatic tires in the UK; the 1911 edition of the Encyclopædia Britannica states that "he spelling'tyre' is not now accepted by the best English authorities, is unrecognized in the US", while Fowler's Modern English Usage of 1926 says that "there is nothing to be said for'tyre', etymologically wrong, as well as needlessly divergent from our own older & the present American usage". However, over the course of the 20th century, tyre became established as the standard British spelling.
The earliest tires were bands of leather iron placed on wooden wheels used on carts and wagons. The tire would be heated in a forge fire, placed over the wheel and quenched, causing the metal to contract and fit on the wheel. A skilled worker, known as a wheelwright, carried out this work; the first patent for what appears to be a standard pneumatic tire appeared in 1847 lodged by the Scottish inventor Robert William Thomson. However, this never went into production; the first practical pneumatic tire was made in 1888 on May Street, Belfast, by Scots-born John Boyd Dunlop, owner of one of Ireland's most prosperous veterinary practices. It was an effort to prevent the headaches of his 10-year-old son Johnnie, while riding his tricycle on rough pavements, his doctor, John Sir John Fagan, had prescribed cycling as an exercise for the boy, was a regular visitor. Fagan participated in designing the first pneumatic tires. Cyclist Willie Hume demonstrated the supremacy of Dunlop's tires in 1889, winning the tire's first-ever races in Ireland and England.
In Dunlop's tire patent specification dated 31 October 1888, his interest is only in its use in cycles and light vehicles. In September 1890, he was made aware of an earlier development but the company kept the information to itself. In 1892, Dunlop's patent was declared invalid because of prior art by forgotten fellow Scot Robert William Thomson of London, although Dunlop is credited with "realizing rubber could withstand the wear and tear of being a tire while retaining its resilience". John Boyd Dunlop and Harvey du Cros together worked through the ensuing considerable difficulties, they employed inventor Charles Kingston Welch and acquired other rights and patents which allowed them some limited protection of their Pneumatic Tyre business's position. Pneumatic Tyre would become Dunlop Tyres; the development of this technology hinged on myriad engineering advances, including the vulcanization of natural rubber using sulfur, as well as by the development of the "clincher" rim for holding the tire in place laterally on the wheel rim.
Synthetic rubbers were invented in the laboratories of Bayer in the 1920s. In 1946, Michelin developed the radial tire method of construction. Michelin had bought the bankrupt Citroën automobile company in 1934, so it was able to fit this new technology immediately; because of its superiority in handling and fuel economy, use of this technology spread throughout Europe and Asia. In the U. S. the outdated bias-ply tire construction persisted, with market share of 87% as late as 1967. Delay was caused by tire and automobile manufacturers in America "concerned about transition costs." In 1968, Consumer Reports, an influential American magazine, acknowledged the superiority of radial construction, setting off a rapid decline in Michelin's competitor technology. In the U. S. the radial tire now has a market share of 100% in automobiles. Today, over 1 billion tires are produced annually in over 400 tire factories. There are 2 aspects to. First, tension in the cords pull on the bead uniformly around the wheel, except where it is reduced above the contact patch.
Second, the bead transfers that net force to the rim. Air pressure, via the ply cords, exerts tensile force on the entire bead surrounding th