1.
Ruler
–
A ruler, sometimes called a rule or line gauge, is an instrument used in geometry, technical drawing, printing, engineering and building to measure distances or to rule straight lines. The ruler is a straightedge which may also contain calibrated lines to measure distances, rulers have long been made from different materials and in a wide range of sizes. Plastics have also used since they were invented, they can be molded with length markings instead of being scribed. Metal is used for more durable rulers for use in the workshop,12 inches or 30 cm in length is useful for a ruler to be kept on a desk to help in drawing. Shorter rulers are convenient for keeping in a pocket, longer rulers, e. g.18 inches are necessary in some cases. Rigid wooden or plastic yardsticks,1 yard long, and meter sticks,1 meter long, are also used, classically, long measuring rods were used for larger projects, now superseded by tape measure or laser rangefinders. Desk rulers are used for three purposes, to measure, to aid in drawing straight lines and as a straight guide for cutting and scoring with a blade. Practical rulers have distance markings along their edges, a line gauge is a type of ruler used in the printing industry. These may be made from a variety of materials, typically metal or clear plastic, units of measurement on a basic line gauge usually include inches, agate, picas, and points. More detailed line gauges may contain sample widths of lines, samples of common type in several point sizes, measuring instruments similar in function to rulers are made portable by folding or retracting into a coil when not in use. When extended for use, they are straight, like a ruler, the illustrations on this page show a 2-meter carpenters rule, which folds down to a length of 24 cm to easily fit in a pocket, and a 5-meter-long tape, which retracts into a small housing. A flexible length measuring instrument which is not necessarily straight in use is the tailors fabric tape measure and it is used to measure around a solid body, e. g. a persons waist measurement, as well as linear measurement, e. g. inside leg. It is rolled up when not in use, taking up little space, a contraction rule is made having larger divisions than standard measures to allow for shrinkage of a metal casting. They may also be known as a shrinkage or shrink rule, a ruler software program can be used to measure pixels on a computer screen or mobile phone. These programs are known as screen rulers. In geometry, a ruler without any marks on it may be used only for drawing lines between points. A straightedge is used to help draw accurate graphs and tables. A ruler and compass construction refers to using an unmarked ruler
2.
Keychain
–
A keychain, key fob or key ring is a small chain, usually made from metal or plastic, that connects a small item to a keyring. The length of a keychain allows an item to be used more easily than if connected directly to a keyring, some keychains allow one or both ends the ability to rotate, keeping the keychain from becoming twisted, while the item is being used. A keychain can also be a link between a keyring and the belt of an individual. It is usually employed by personnel whose job demands frequent use of keys, such as a security guard, prison officer, the chain is often retractable, and therefore may be a nylon rope, instead of an actual metal chain. The chain ensures that the keys attached to the individual using them, makes accidental loss less likely. Keychains are one of the most common souvenir and advertising items, keychains are commonly used to promote businesses. A standard advertising keychain will carry the name and contact information. In the 1950s and 1960s, with the improvement of manufacturing techniques. Businesses could place their names on promotional keychains that were three-dimensional for less cost than the standard metal keychains, keychains are small and inexpensive enough to become promotional items for larger national companies that might give them out by the millions. For example, with the launch of a new movie or television show, keychains that currently hold keys are an item that is never long misplaced by the owner. People sometimes attach their keychain to their belt to avoid loss or to allow access to it. Many keychains also offer functions that the owner wants easily accessible as well and these include an army knife, bottle opener, an electronic organizer, scissors, address book, family photos, nail clipper, pill case and even pepper spray. Modern cars often include a keychain that serves as a remote to lock/unlock the car or even start the engine, an electronic key finder is also a useful item found on many keys that will beep when summoned for quick finding when misplaced. A keyring or split ring is a ring that holds keys and other small items, other types of keyrings are made of leather, wood and rubber. Keyring was invented in the 19th century by Alexander Parkes, the most common form of the keyring is a single piece of metal in a double loop. Either end of the loop can be pried open to allow a key to be inserted, novelty carabiners are also commonly used as keyrings for ease of access and exchange. Often the keyring is adorned with a key fob for self-identification, other forms of rings may use a single loop of metal or plastic with a mechanism to open and securely close the loop. The word fob may be linked to the low German dialect for the word Fuppe, meaning pocket, however, fob pockets were pockets meant to deter thieves
3.
Surveying
–
Surveying or land surveying is the technique, profession, and science of determining the terrestrial or three-dimensional position of points and the distances and angles between them. A land surveying professional is called a land surveyor, Surveyors work with elements of geometry, trigonometry, regression analysis, physics, engineering, metrology, programming languages and the law. Surveying has been an element in the development of the environment since the beginning of recorded history. The planning and execution of most forms of construction require it and it is also used in transport, communications, mapping, and the definition of legal boundaries for land ownership. It is an important tool for research in other scientific disciplines. Basic surveyance has occurred since humans built the first large structures, the prehistoric monument at Stonehenge was set out by prehistoric surveyors using peg and rope geometry. In ancient Egypt, a rope stretcher would use simple geometry to re-establish boundaries after the floods of the Nile River. The almost perfect squareness and north-south orientation of the Great Pyramid of Giza, built c.2700 BC, the Groma instrument originated in Mesopotamia. The mathematician Liu Hui described ways of measuring distant objects in his work Haidao Suanjing or The Sea Island Mathematical Manual, the Romans recognized land surveyors as a profession. They established the basic measurements under which the Roman Empire was divided, Roman surveyors were known as Gromatici. In medieval Europe, beating the bounds maintained the boundaries of a village or parish and this was the practice of gathering a group of residents and walking around the parish or village to establish a communal memory of the boundaries. Young boys were included to ensure the memory lasted as long as possible, in England, William the Conqueror commissioned the Domesday Book in 1086. It recorded the names of all the owners, the area of land they owned, the quality of the land. It did not include maps showing exact locations, abel Foullon described a plane table in 1551, but it is thought that the instrument was in use earlier as his description is of a developed instrument. Gunters chain was introduced in 1620 by English mathematician Edmund Gunter and it enabled plots of land to be accurately surveyed and plotted for legal and commercial purposes. Leonard Digges described a Theodolite that measured horizontal angles in his book A geometric practice named Pantometria, joshua Habermel created a theodolite with a compass and tripod in 1576. Johnathon Sission was the first to incorporate a telescope on a theodolite in 1725, in the 18th century, modern techniques and instruments for surveying began to be used. Jesse Ramsden introduced the first precision theodolite in 1787 and it was an instrument for measuring angles in the horizontal and vertical planes
4.
Sewing
–
Sewing is the craft of fastening or attaching objects using stitches made with a needle and thread. Sewing is one of the oldest of the arts, arising in the Paleolithic era. For thousands of years, all sewing was done by hand, fine hand sewing is a characteristic of high-quality tailoring, haute couture fashion, and custom dressmaking, and is pursued by both textile artists and hobbyists as a means of creative expression. The first known use of the sewing was in the 14th century. Sewing has an ancient history estimated to begin during the Paleolithic Age, Sewing was used to stitch together animal hides for clothing and for shelter. The weaving of cloth from natural fibres originated in the Middle East around 4000 BCE, and perhaps earlier during the Neolithic Age, during the Middle Ages, Europeans who could afford it employed seamstresses and tailors. Sewing for the most part was an occupation, and most sewing before the 19th century was practical. Clothing was an investment for most people, and women had an important role in extending the longevity of items of clothing. Clothing that was faded would be turned inside-out so that it could continue to be worn, once clothing became worn or torn, it would be taken apart and the reusable cloth sewn together into new items of clothing, made into quilts, or otherwise put to practical use. The many steps involved in making clothing from scratch meant that women often bartered their expertise in a skill with one another. Decorative needlework such as embroidery was a skill, and young women with the time. From the Middle Ages to the 17th century, sewing tools such as needles, decorative embroidery was valued in many cultures worldwide. Some examples are the Cretan Open Filling stitch, Romanian Couching or Oriental Couching, the stitches associated with embroidery spread by way of the trade routes that were active during the Middle Ages. European imperial settlements also spread embroidery and sewing techniques worldwide, however, there are instances of sewing techniques indigenous to cultures in distant locations from one another, where cross-cultural communication would have been historically unlikely. For example, a method of reverse appliqué known to areas of South America is also known to Southeast Asia, the Industrial Revolution shifted the production of textiles from the household to the mills. In the early decades of the Industrial Revolution, the machinery produced whole cloth, the worlds first sewing machine was patented in 1790 by Thomas Saint. By the early 1840s, other early sewing machines began to appear, by the 1850s, Isaac Singer developed the first sewing machines that could operate quickly and accurately and surpass the productivity of a seamstress or tailor sewing by hand. While much clothing was produced at home by female members of the family
5.
Carpentry
–
Carpentry in the United States is almost always done by men. With 98. 5% of carpenters being male, it was the fourth most male-dominated occupation in the country in 1999, Carpenters are usually the first tradesmen on a job and the last to leave. Carpenters normally framed post-and-beam buildings until the end of the 19th century and it is also common that the skill can be learned by gaining work experience other than a formal training program, which may be the case in many places. The word carpenter is the English rendering of the Old French word carpentier which is derived from the Latin carpentrius, the Middle English and Scots word was wright, which could be used in compound forms such as wheelwright or boatwright. An easy way to envisage this is that first fix work is all that is done before plastering takes place, second fix is done after plastering takes place. Second fix work, the construction of such as skirting boards, architraves. Carpentry is also used to construct the formwork into which concrete is poured during the building of such as roads. In the UK, the skill of making timber formwork for poured, or in situ, although the. work of a carpenter and joiner are often combined. Joiner is less common than the finish carpenter or cabinetmaker. The terms housewright and barnwright were used historically, now used by carpenters who work using traditional methods. Someone who builds custom concrete formwork is a form carpenter, wood is one of mankinds oldest building materials. The ability to shape wood improved with technological advances from the age to the bronze age to the iron age. The oldest surviving, complete text is Vitruvius ten books collectively titled De architectura which discusses some carpentry. By the 16th century sawmills were coming into use in Europe, the founding of America was partly based on a desire to extract resources from the new continent including wood for use in ships and buildings in Europe. In the 18th century part of the Industrial Revolution was the invention of the steam engine and these technologies combined with the invention of the circular saw led to the development of balloon framing which was the beginning of the decline of traditional timber framing. The 19th century saw the development of engineering and distribution which allowed the development of hand-held power tools, wire nails. In the 20th century portland cement came into use and concrete foundations allowed carpenters to do away with heavy timber sills. Also, drywall came into common use replacing lime plaster on wooden lath, plywood, engineered lumber and chemically treated lumber also came into use
6.
Ancient Rome
–
In its many centuries of existence, the Roman state evolved from a monarchy to a classical republic and then to an increasingly autocratic empire. Through conquest and assimilation, it came to dominate the Mediterranean region and then Western Europe, Asia Minor, North Africa and it is often grouped into classical antiquity together with ancient Greece, and their similar cultures and societies are known as the Greco-Roman world. Ancient Roman civilisation has contributed to modern government, law, politics, engineering, art, literature, architecture, technology, warfare, religion, language and society. Rome professionalised and expanded its military and created a system of government called res publica, the inspiration for modern republics such as the United States and France. By the end of the Republic, Rome had conquered the lands around the Mediterranean and beyond, its domain extended from the Atlantic to Arabia, the Roman Empire emerged with the end of the Republic and the dictatorship of Augustus Caesar. 721 years of Roman-Persian Wars started in 92 BC with their first war against Parthia and it would become the longest conflict in human history, and have major lasting effects and consequences for both empires. Under Trajan, the Empire reached its territorial peak, Republican mores and traditions started to decline during the imperial period, with civil wars becoming a prelude common to the rise of a new emperor. Splinter states, such as the Palmyrene Empire, would divide the Empire during the crisis of the 3rd century. Plagued by internal instability and attacked by various migrating peoples, the part of the empire broke up into independent kingdoms in the 5th century. This splintering is a landmark historians use to divide the ancient period of history from the pre-medieval Dark Ages of Europe. King Numitor was deposed from his throne by his brother, Amulius, while Numitors daughter, Rhea Silvia, because Rhea Silvia was raped and impregnated by Mars, the Roman god of war, the twins were considered half-divine. The new king, Amulius, feared Romulus and Remus would take back the throne, a she-wolf saved and raised them, and when they were old enough, they returned the throne of Alba Longa to Numitor. Romulus became the source of the citys name, in order to attract people to the city, Rome became a sanctuary for the indigent, exiled, and unwanted. This caused a problem for Rome, which had a large workforce but was bereft of women, Romulus traveled to the neighboring towns and tribes and attempted to secure marriage rights, but as Rome was so full of undesirables they all refused. Legend says that the Latins invited the Sabines to a festival and stole their unmarried maidens, leading to the integration of the Latins, after a long time in rough seas, they landed at the banks of the Tiber River. Not long after they landed, the men wanted to take to the sea again, one woman, named Roma, suggested that the women burn the ships out at sea to prevent them from leaving. At first, the men were angry with Roma, but they realized that they were in the ideal place to settle. They named the settlement after the woman who torched their ships, the Roman poet Virgil recounted this legend in his classical epic poem the Aeneid
7.
Integrated circuit
–
An integrated circuit or monolithic integrated circuit is a set of electronic circuits on one small flat piece of semiconductor material, normally silicon. The ICs mass production capability, reliability and building-block approach to circuit design ensured the rapid adoption of standardized ICs in place of using discrete transistors. ICs are now used in all electronic equipment and have revolutionized the world of electronics. Computers, mobile phones, and other home appliances are now inextricable parts of the structure of modern societies, made possible by the small size. These advances, roughly following Moores law, allow a computer chip of 2016 to have millions of times the capacity, ICs have two main advantages over discrete circuits, cost and performance. Cost is low because the chips, with all their components, are printed as a unit by photolithography rather than being constructed one transistor at a time, furthermore, packaged ICs use much less material than discrete circuits. Performance is high because the ICs components switch quickly and consume little power because of their small size, the main disadvantage of ICs is the high cost to design them and fabricate the required photomasks. This high initial cost means ICs are only practical when high production volumes are anticipated, Circuits meeting this definition can be constructed using many different technologies, including thin-film transistor, thick film technology, or hybrid integrated circuit. However, in general usage integrated circuit has come to refer to the single-piece circuit construction originally known as a integrated circuit. Jacobi disclosed small and cheap hearing aids as typical industrial applications of his patent, an immediate commercial use of his patent has not been reported. The idea of the circuit was conceived by Geoffrey Dummer. Dummer presented the idea to the public at the Symposium on Progress in Quality Electronic Components in Washington and he gave many symposia publicly to propagate his ideas, and unsuccessfully attempted to build such a circuit in 1956. A precursor idea to the IC was to create small ceramic squares, Components could then be integrated and wired into a bidimensional or tridimensional compact grid. This idea, which seemed very promising in 1957, was proposed to the US Army by Jack Kilby, however, as the project was gaining momentum, Kilby came up with a new, revolutionary design, the IC. In his patent application of 6 February 1959, Kilby described his new device as a body of semiconductor material … wherein all the components of the circuit are completely integrated. The first customer for the new invention was the US Air Force, Kilby won the 2000 Nobel Prize in Physics for his part in the invention of the integrated circuit. His work was named an IEEE Milestone in 2009, half a year after Kilby, Robert Noyce at Fairchild Semiconductor developed his own idea of an integrated circuit that solved many practical problems Kilbys had not. Noyces design was made of silicon, whereas Kilbys chip was made of germanium, Noyce credited Kurt Lehovec of Sprague Electric for the principle of p–n junction isolation, a key concept behind the IC
8.
Laser
–
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term laser originated as an acronym for light amplification by stimulated emission of radiation, the first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light coherently, spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances, Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum, i. e. they can emit a single color of light. Temporal coherence can be used to produce pulses of light as short as a femtosecond, Lasers are distinguished from other light sources by their coherence. Spatial coherence is typically expressed through the output being a narrow beam, Laser beams can be focused to very tiny spots, achieving a very high irradiance, or they can have very low divergence in order to concentrate their power at a great distance. Temporal coherence implies a polarized wave at a single frequency whose phase is correlated over a great distance along the beam. A beam produced by a thermal or other incoherent light source has an amplitude and phase that vary randomly with respect to time and position. Lasers are characterized according to their wavelength in a vacuum, most single wavelength lasers actually produce radiation in several modes having slightly differing frequencies, often not in a single polarization. Although temporal coherence implies monochromaticity, there are lasers that emit a broad spectrum of light or emit different wavelengths of light simultaneously, there are some lasers that are not single spatial mode and consequently have light beams that diverge more than is required by the diffraction limit. However, all devices are classified as lasers based on their method of producing light. Lasers are employed in applications where light of the spatial or temporal coherence could not be produced using simpler technologies. The word laser started as an acronym for light amplification by stimulated emission of radiation, in the early technical literature, especially at Bell Telephone Laboratories, the laser was called an optical maser, this term is now obsolete. A laser that produces light by itself is technically an optical rather than an optical amplifier as suggested by the acronym. It has been noted that the acronym LOSER, for light oscillation by stimulated emission of radiation. With the widespread use of the acronym as a common noun, optical amplifiers have come to be referred to as laser amplifiers. The back-formed verb to lase is frequently used in the field, meaning to produce light, especially in reference to the gain medium of a laser. Further use of the laser and maser in an extended sense, not referring to laser technology or devices, can be seen in usages such as astrophysical maser
9.
Mickey Mantle
–
Mickey Charles Mantle, nicknamed The Commerce Comet and The Mick, was an American professional baseball player. Mantle played his entire Major League Baseball career with the New York Yankees as a fielder and first baseman. Mantle was one of the best players and sluggers, and is regarded by many as the greatest switch hitter in baseball history, Mantle was inducted into the National Baseball Hall of Fame in 1974 and was elected to the Major League Baseball All-Century Team in 1999. Mantle was arguably the greatest offensive threat of any center fielder in baseball history and he has the highest career OPS+ of any center fielder and he had the highest stolen base percentage in history at the time of his retirement. He also had an excellent 0.984 fielding percentage when playing center field, Mantle was noted for his ability to hit for both average and power, especially tape measure home runs. He hit 536 MLB career home runs, batted.300 or more ten times, Mantle won the Triple Crown in 1956, leading the major leagues in batting average, home runs, and runs batted in, he later wrote a book about his best year in baseball. He was an All-Star for 16 seasons, playing in 16 of the 20 All-Star Games that were played and he was an American League Most Valuable Player three times and a Gold Glove winner once. Mantle appeared in 12 World Series including seven championships, and holds World Series records for the most home runs, RBIs, extra-base hits, runs, walks, and total bases. Mantle was born on October 20,1931 in Spavinaw, Oklahoma and he was of at least partial English ancestry, his great-grandfather, George Mantle, left Brierley Hill, in Englands Black Country, in 1848. Mutt named his son in honor of Mickey Cochrane, a Hall of Fame catcher, later in his life, Mantle expressed relief that his father had not known Cochranes true first name, as he would have hated to be named Gordon. Mantle spoke warmly of his father, and said he was the bravest man he ever knew, No boy ever loved his father more, he said. His grandfather died at the age of 60 in 1944, when Mantle was four years old, his family moved to the nearby town of Commerce, Oklahoma, where his father worked in lead and zinc mines. As a teenager, Mantle rooted for the St. Louis Cardinals, Mantle was an all-around athlete at Commerce High School, playing basketball as well as football in addition to his first love, baseball. His football playing nearly ended his athletic career, kicked in the left shin during a practice game during his sophomore year, Mantle developed osteomyelitis in his left ankle, a crippling disease that was incurable just a few years earlier. Mantle began his baseball career in Kansas with the semi-professional Baxter Springs Whiz Kids. In 1948, Yankees scout Tom Greenwade came to Baxter Springs to watch Mantles teammate, during the game, Mantle hit three home runs. Greenwade returned in 1949, after Mantles high school graduation, to sign Mantle to a league contract. Mantle signed for $140 per month with a $1,500 signing bonus, Mantle was assigned to the Yankees Class-D Independence Yankees of the Kansas–Oklahoma–Missouri League, where he played shortstop
10.
Construction
–
Construction is the process of constructing a building or infrastructure. Construction as an industry comprises six to nine percent of the domestic product of developed countries. Construction starts with planning, design, and financing, and continues until the project is built, large-scale construction requires collaboration across multiple disciplines. An architect normally manages the job, and a manager, design engineer. For the successful execution of a project, effective planning is essential, the largest construction projects are referred to as megaprojects. Construction is a term meaning the art and science to form objects, systems, or organizations. Construction is used as a verb, the act of building, and a noun, how a building was built, in general, there are three sectors of construction, buildings, infrastructure and industrial. Building construction is further divided into residential and non-residential. Infrastructure is often called heavy/highway, heavy civil or heavy engineering and it includes large public works, dams, bridges, highways, water/wastewater and utility distribution. Industrial includes refineries, process chemical, power generation, mills, there are other ways to break the industry into sectors or markets. Engineering News-Record is a magazine for the construction industry. Each year, ENR compiles and reports on data about the size of design and they publish a list of the largest companies in the United States and also a list the largest global firms. In 2014, ENR compiled the data in nine market segments and it was divided as transportation, petroleum, buildings, power, industrial, water, manufacturing, sewer/waste, telecom, hazardous waste plus a tenth category for other projects. In their reporting on the Top 400, they used data on transportation, sewer, hazardous waste, the Standard Industrial Classification and the newer North American Industry Classification System have a classification system for companies that perform or otherwise engage in construction. To recognize the differences of companies in this sector, it is divided into three subsectors, building construction, heavy and civil engineering construction, and specialty trade contractors, there are also categories for construction service firms and construction managers. Building construction is the process of adding structure to real property or construction of buildings, the majority of building construction jobs are small renovations, such as addition of a room, or renovation of a bathroom. Often, the owner of the property acts as laborer, paymaster, for this reason, those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome. Residential construction practices, technologies, and resources must conform to local building authority regulations, materials readily available in the area generally dictate the construction materials used
11.
Plywood
–
Plywood is a sheet material manufactured from thin layers or plies of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is a wood from the family of manufactured boards which includes medium-density fibreboard. All plywoods bind resin and wood fibre sheets to form a composite material, there is usually an odd number of plies, so that the sheet is balanced—this reduces warping. Because plywood is bonded with grains running against one another and with an odd number of composite parts, the word ply derives from the French verb plier, to fold, from the Latin verb plico, from the ancient Greek verb πλέκω. In 1797 Samuel Bentham applied for patents covering several machines to produce veneers, in his patent applications, he described the concept of laminating several layers of veneer with glue to form a thicker piece – the first description of what we now call plywood. Samuel Bentham was a British naval engineer with many shipbuilding inventions to his credit. Veneers at the time of Bentham were flat sawn, rift sawn or quarter sawn, i. e. cut along or across the log manually in different angles to the grain and thus limited in width and length. One can thus presume that rotary lathe plywood manufacture was a process in France in the 1860s. Plywood was introduced into the United States in 1865 and industrial production started shortly after, in 1928, the first standard-sized 4 ft by 8 ft plywood sheets were introduced in the United States for use as a general building material. Artists use plywood as a support for paintings to replace traditional canvas or cardboard. Ready-made artist boards for oil painting in three-layered plywood were produced, in India, plywood is more commonly called Kitply after a leading brand which pioneered the concept of waterproof plywood in the early 1970s. A typical plywood panel has face veneers of a higher grade than the core veneers, the principal function of the core layers is to increase the separation between the outer layers where the bending stresses are highest, thus increasing the panels resistance to bending. As a result, thicker panels can span greater distances under the same loads, in bending, the maximum stress occurs in the outermost layers, one in tension, the other in compression. Bending stress decreases from the maximum at the layers to nearly zero at the central layer. Shear stress, by contrast, is higher in the center of the panel, the most common dimension is 1.2 by 2.4 metres or the slightly larger imperial dimension of 4 feet ×8 feet. Plies vary in thickness from 1.4 mm to 4.3 mm, the number of plies—which is always odd—depends on the thickness and grade of the sheet. Roofing can use the thinner 5/8 plywood, subfloors are at least 3/4 thick, the thickness depending on the distance between floor joists. T&G plywood is usually found in the 1/2 to 1 range, hardwood plywood is made out of wood from angiosperm trees and used for demanding end uses
12.
Drywall
–
Drywall is a panel made of calcium sulfate dihydrate with or without additives and normally pressed between a facer and a backer. It is used to make walls and ceilings. The plaster is mixed with fibre, plasticizer, foaming agent, and various additives that can decrease mildew, increase fire resistance, drywall construction became prevalent in North America as a speedier alternative to traditional lath and plaster. The first plasterboard plant in the UK was opened in 1888 in Rochester, Sackett Board was invented in 1894 by Augustine Sackett and Fred Kane. It was made by layering plaster within four plies of wool felt paper, sheets were 36 ×36 × 1/4 thick with open edges. Gypsum board evolved between 1910 and 1930 beginning with wrapped board edges and elimination of the two layers of felt paper in favor of paper-based facings. In 1910 United States Gypsum Corporation bought Sackett Plaster Board Company, providing efficiency of installation, it was developed additionally as a measure of fire resistance. Later air entrainment technology made boards lighter and less brittle, then joint treatment materials, rock lath was an early substrate for plaster. As it evolved, it was faced with paper impregnated with gypsum crystals that bonded with the applied facing layer of plaster, a wallboard panel consists of a layer of gypsum plaster sandwiched between two layers of paper. The raw gypsum, CaSO4·2 H2O, is heated to drive off the water then slightly rehydrated to produce the hemihydrate of calcium sulfate, the board is then formed by sandwiching a core of the wet mixture between two sheets of heavy paper or fibreglass mats. When the core sets it is dried in a large drying chamber. Drying chambers typically use natural gas today, to dry 1 MSF of wallboard, between 1,750,000 and 2,490,000 BTU is required. Organic dispersants/plasticisers are used so the slurry will flow during manufacture, coal-fired power stations include devices called scrubbers to remove sulphur from their exhaust emissions. The sulphur is absorbed by powdered limestone in a process called flue-gas desulphurization and this is commonly used in drywall construction in the United States and elsewhere. Drywall panels in the United States are manufactured in 48-inch, 54-inch and 96-inch wide panels in varying lengths to suit the application, lengths up to 12-feet are commonly available, though the most common length is 8-feet. Common panel thicknesses are 1⁄2-inch and 5⁄8-inch, with panels also available in 1⁄4-inch, 3⁄8-inch, 3/4-inch and 1-inch for specific applications, in Europe plasterboard is manufactured in metric sizes, with the common sizes being corollaries of old imperial sizes. Most plasterboard is made in 120 cm-wide sheets, though 90 cm and 60 cm wide sheets are also made,120 cm wide plasterboard is most commonly made in 240 cm lengths, though 250,260,270,280,300 cm and even longer are commonly available. Thicknesses of plasterboard available are 9.5 mm to 25 mm, however four side chamfered drywall is not currently offered by major UK manufacturers for general use
Media related to Tape measures at Wikimedia Commons
