1.
Agriculture
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Agriculture is the cultivation and breeding of animals, plants and fungi for food, fiber, biofuel, medicinal plants and other products used to sustain and enhance human life. Agriculture was the key development in the rise of human civilization. The study of agriculture is known as agricultural science, the history of agriculture dates back thousands of years, and its development has been driven and defined by greatly different climates, cultures, and technologies. Industrial agriculture based on large-scale monoculture farming has become the dominant agricultural methodology, genetically modified organisms are an increasing component of agriculture, although they are banned in several countries. Agricultural food production and water management are increasingly becoming global issues that are fostering debate on a number of fronts, the major agricultural products can be broadly grouped into foods, fibers, fuels, and raw materials. Specific foods include cereals, vegetables, fruits, oils, meats, fibers include cotton, wool, hemp, silk and flax. Raw materials include lumber and bamboo, other useful materials are also produced by plants, such as resins, dyes, drugs, perfumes, biofuels and ornamental products such as cut flowers and nursery plants. The word agriculture is a late Middle English adaptation of Latin agricultūra, from ager, field, Agriculture usually refers to human activities, although it is also observed in certain species of ant, termite and ambrosia beetle. To practice agriculture means to use resources to produce commodities which maintain life, including food, fiber, forest products, horticultural crops. This definition includes arable farming or agronomy, and horticulture, all terms for the growing of plants, even then, it is acknowledged that there is a large amount of knowledge transfer and overlap between silviculture and agriculture. In traditional farming, the two are often combined even on small landholdings, leading to the term agroforestry, Agriculture began independently in different parts of the globe, and included a diverse range of taxa. At least 11 separate regions of the Old and New World were involved as independent centers of origin, wild grains were collected and eaten from at least 105,000 years ago. Pigs were domesticated in Mesopotamia around 15,000 years ago, rice was domesticated in China between 13,500 and 8,200 years ago, followed by mung, soy and azuki beans. Sheep were domesticated in Mesopotamia between 13,000 and 11,000 years ago. From around 11,500 years ago, the eight Neolithic founder crops, emmer and einkorn wheat, hulled barley, peas, lentils, bitter vetch, chick peas and flax were cultivated in the Levant. Cattle were domesticated from the aurochs in the areas of modern Turkey. In the Andes of South America, the potato was domesticated between 10,000 and 7,000 years ago, along with beans, coca, llamas, alpacas, sugarcane and some root vegetables were domesticated in New Guinea around 9,000 years ago. Sorghum was domesticated in the Sahel region of Africa by 7,000 years ago, cotton was domesticated in Peru by 5,600 years ago, and was independently domesticated in Eurasia at an unknown time
2.
Irrigation
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Irrigation is the method in which a controlled amount of water is supplied to plants at regular intervals for agriculture. It is used to assist in the growing of crops, maintenance of landscapes. Additionally, irrigation also has a few uses in crop production. In contrast, agriculture that only on direct rainfall is referred to as rain-fed or dry land farming. Irrigation systems are used for dust suppression, disposal of sewage. Irrigation is often studied together with drainage, which is the natural or artificial removal of surface and sub-surface water from a given area, Irrigation has been a central feature of agriculture for over 5,000 years and is the product of many cultures. Historically, it was the basis for economies and societies across the globe, archaeological investigation has found evidence of irrigation where the natural rainfall was insufficient to support crops for rainfed agriculture. Ancient Egyptians practiced Basin irrigation using the flooding of the Nile to inundate land plots which had surrounded by dykes. The flood water was held until the sediment had settled before the surplus was returned to the watercourse. The Ancient Nubians developed a form of irrigation by using a device called a sakia. Irrigation began in Nubia some time between the third and second millennium BCE and it largely depended upon the flood waters that would flow through the Nile River and other rivers in what is now the Sudan. In sub-Saharan Africa irrigation reached the Niger River region cultures and civilizations by the first or second millennium BCE and was based on wet season flooding, terrace irrigation is evidenced in pre-Columbian America, early Syria, India, and China. These canals are the earliest record of irrigation in the New World, traces of a canal possibly dating from the 5th millennium BCE were found under the 4th millennium canal. Large scale agriculture was practiced and a network of canals was used for the purpose of irrigation. Ancient Persia as far back as the 6th millennium BCE, where barley was grown in areas where the rainfall was insufficient to support such a crop. The Qanats, developed in ancient Persia in about 800 BCE, are among the oldest known irrigation methods still in use today and they are now found in Asia, the Middle East and North Africa. The system comprises a network of wells and gently sloping tunnels driven into the sides of cliffs. The noria, a wheel with clay pots around the rim powered by the flow of the stream, was first brought into use at about this time
3.
Irrigation sprinkler
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Irrigation sprinklers are sprinklers providing irrigation to agriculture, crops, vegetation, or for recreation, as a cooling system, or for the control of airborne dust, landscaping and golf courses. The sprinkler system irrigates the field and thus it is used in sandy areas as it checks the wastage of water through seepage. Sprinkler irrigation is a method of applying irrigation water which is similar to natural rainfall, water is distributed through a system of pipes usually by pumping. It is then sprayed into the air through sprinklers so that it breaks up into small water drops which fall to the ground, the pump supply system, sprinklers and operating conditions must be designed to enable a uniform application of water. Sprinklers that spray in a fixed pattern are generally called sprays or spray heads, sprays are not usually designed to operate at pressures, due to misting problems that may develop. Higher pressure sprinklers that themselves move in a circle are driven by a drive, gear drive. These can be designed to rotate in a full or partial circle.5 to 1.9 inches, in addition to irrigation, guns are used for industrial applications such as dust suppression and logging. Many irrigation sprinklers are buried in the ground along with their plumbing, although above ground. Most irrigation sprinklers operate through electric and hydraulic technology and are grouped together in zones that can be turned on. Home lawn sprinklers vary widely in their size, cost, and they include impact sprinklers, oscillating sprinklers, drip sprinklers, and underground sprinkler systems. Small sprinklers are available at home and garden stores or hardware stores for small costs and these are often attached to an outdoor water faucet and are placed only temporarily. Other systems may be installed permanently in the ground and are attached permanently to a homes plumbing system. An ingenious domestic sprinkler made by Nomad called a set-and-forget tractor sprinkler was used in Australia in the 1950s, water pressure ensured that the sprinkler slowly moved across a lawn. Permanently installed systems may operate on timers or other automated processes. They are occasionally installed with retractable heads for aesthetic and practical reasons and these often are programmed to operate on a schedule and irrigate a piece of land in zones. Underground sprinklers function through means of electronic and hydraulic technology. This valve and all of the sprinklers that will be activated by this valve are known as a zone, upon activation, the solenoid, which sits on top of the valve is magnetized lifting a small stainless steel plunger in its center. By doing this, the activated plunger allows air to escape from the top of a diaphragm located in the center of the valve
4.
Circle
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A circle is a simple closed shape in Euclidean geometry. The distance between any of the points and the centre is called the radius, a circle is a simple closed curve which divides the plane into two regions, an interior and an exterior. Annulus, the object, the region bounded by two concentric circles. Arc, any connected part of the circle, centre, the point equidistant from the points on the circle. Chord, a segment whose endpoints lie on the circle. Circumference, the length of one circuit along the circle, or the distance around the circle and it is a special case of a chord, namely the longest chord, and it is twice the radius. Disc, the region of the bounded by a circle. Lens, the intersection of two discs, passant, a coplanar straight line that does not touch the circle. Radius, a line segment joining the centre of the circle to any point on the circle itself, or the length of such a segment, sector, a region bounded by two radii and an arc lying between the radii. Segment, a region, not containing the centre, bounded by a chord, secant, an extended chord, a coplanar straight line cutting the circle at two points. Semicircle, an arc that extends from one of a diameters endpoints to the other, in non-technical common usage it may mean the diameter, arc, and its interior, a two dimensional region, that is technically called a half-disc. A half-disc is a case of a segment, namely the largest one. Tangent, a straight line that touches the circle at a single point. The word circle derives from the Greek κίρκος/κύκλος, itself a metathesis of the Homeric Greek κρίκος, the origins of the words circus and circuit are closely related. The circle has been known since before the beginning of recorded history, natural circles would have been observed, such as the Moon, Sun, and a short plant stalk blowing in the wind on sand, which forms a circle shape in the sand. The circle is the basis for the wheel, which, with related inventions such as gears, in mathematics, the study of the circle has helped inspire the development of geometry, astronomy and calculus. Some highlights in the history of the circle are,1700 BCE – The Rhind papyrus gives a method to find the area of a circular field. The result corresponds to 256/81 as a value of π.300 BCE – Book 3 of Euclids Elements deals with the properties of circles
5.
Electric motor
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An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this is the conversion of energy into electrical energy and is done by an electric generator. In normal motoring mode, most electric motors operate through the interaction between an electric motors magnetic field and winding currents to generate force within the motor, small motors may be found in electric watches. General-purpose motors with highly standardized dimensions and characteristics provide convenient mechanical power for industrial use, the largest of electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors may be classified by electric power source type, internal construction, application, type of motion output, perhaps the first electric motors were simple electrostatic devices created by the Scottish monk Andrew Gordon in the 1740s. The theoretical principle behind production of force by the interactions of an electric current. The conversion of energy into mechanical energy by electromagnetic means was demonstrated by the British scientist Michael Faraday in 1821. A free-hanging wire was dipped into a pool of mercury, on which a permanent magnet was placed, when a current was passed through the wire, the wire rotated around the magnet, showing that the current gave rise to a close circular magnetic field around the wire. This motor is often demonstrated in experiments, brine substituting for toxic mercury. Though Barlows wheel was a refinement to this Faraday demonstration. In 1827, Hungarian physicist Ányos Jedlik started experimenting with electromagnetic coils, after Jedlik solved the technical problems of the continuous rotation with the invention of the commutator, he called his early devices electromagnetic self-rotors. Although they were used only for instructional purposes, in 1828 Jedlik demonstrated the first device to contain the three components of practical DC motors, the stator, rotor and commutator. The device employed no permanent magnets, as the fields of both the stationary and revolving components were produced solely by the currents flowing through their windings. His motor set a record which was improved only four years later in September 1838 by Jacobi himself. His second motor was powerful enough to drive a boat with 14 people across a wide river and it was not until 1839/40 that other developers worldwide managed to build motors of similar and later also of higher performance. The first commutator DC electric motor capable of turning machinery was invented by the British scientist William Sturgeon in 1832, following Sturgeons work, a commutator-type direct-current electric motor made with the intention of commercial use was built by the American inventor Thomas Davenport, which he patented in 1837. The motors ran at up to 600 revolutions per minute, and powered machine tools, due to the high cost of primary battery power, the motors were commercially unsuccessful and Davenport went bankrupt. Several inventors followed Sturgeon in the development of DC motors but all encountered the same battery power cost issues, no electricity distribution had been developed at the time
6.
Cotton
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Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus Gossypium in the family of Malvaceae. The fiber is almost pure cellulose, under natural conditions, the cotton bolls will tend to increase the dispersal of the seeds. The plant is a native to tropical and subtropical regions around the world, including the Americas, Africa. The greatest diversity of wild species is found in Mexico, followed by Australia. Cotton was independently domesticated in the Old and New Worlds, the fiber is most often spun into yarn or thread and used to make a soft, breathable textile. Current estimates for world production are about 25 million tonnes or 110 million bales annually, China is the worlds largest producer of cotton, but most of this is used domestically. The United States has been the largest exporter for many years, in the United States, cotton is usually measured in bales, which measure approximately 0.48 cubic meters and weigh 226.8 kilograms. Cotton cultivation in the region is dated to the Indus Valley Civilization, the Indus cotton industry was well-developed and some methods used in cotton spinning and fabrication continued to be used until the industrialization of India. Between 2000 and 1000 BC cotton became widespread across much of India, for example, it has been found at the site of Hallus in Karnataka dating from around 1000 BC. Cotton fabrics discovered in a cave near Tehuacán, Mexico have been dated to around 5800 BC, the domestication of Gossypium hirsutum in Mexico is dated between 3400 and 2300 BC. Cotton was grown upriver, made into nets, and traded with fishing villages along the coast for supplies of fish. The Spanish who came to Mexico and Peru in the early 16th century found the people growing cotton and this may be a reference to tree cotton, Gossypium arboreum, which is a native of the Indian subcontinent. According to the Columbia Encyclopedia, Cotton has been spun, woven and it clothed the people of ancient India, Egypt, and China. Hundreds of years before the Christian era, cotton textiles were woven in India with matchless skill, in Iran, the history of cotton dates back to the Achaemenid era, however, there are few sources about the planting of cotton in pre-Islamic Iran. The planting of cotton was common in Merv, Ray and Pars of Iran, in Persian poets poems, especially Ferdowsis Shahname, there are references to cotton. Marco Polo refers to the products of Persia, including cotton. John Chardin, a French traveler of the 17th century who visited the Safavid Persia, during the Han dynasty, cotton was grown by Chinese peoples in the southern Chinese province of Yunnan. Mohamed Ali Pasha accepted the proposition and granted himself the monopoly on the sale and export of cotton in Egypt, and later dictated cotton should be grown in preference to other crops
7.
Hot-dip galvanization
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Hot-dip galvanization is a form of galvanization. Galvanized steel can be welded, however, one must exercise caution around the resulting toxic zinc fumes, galvanized steel is suitable for high-temperature applications of up to 392 °F. The use of galvanized steel at temperatures above this will result in peeling of the zinc at the metallic layer. Like other corrosion protection systems, galvanizing protects steel by acting as a barrier between steel and the atmosphere, however, zinc is a more electropositive metal in comparison to steel. The process of hot-dip galvanizing results in a bond between zinc and steel with a series of distinct iron-zinc alloys. The resulting coated steel can be used in much the way as uncoated. A typical hot-dip galvanizing line operates as follows, Steel is cleaned using a caustic solution and this removes oil/grease, dirt, and paint. The caustic cleaning solution is rinsed off, the steel is pickled in an acidic solution to remove mill scale. The pickling solution is rinsed off, a flux, often zinc ammonium chloride is applied to the steel to inhibit oxidation of the cleaned surface upon exposure to air. The flux is allowed to dry on the steel and aids in the process of the liquid zinc wetting and adhering to the steel, the steel is dipped into the molten zinc bath and held there until the temperature of the steel equilibrates with that of the bath. The steel is cooled in a tank to reduce its temperature. Lead is either added to primary Z1 grade zinc or already contained in used secondary zinc, a third, declining method is to use low Z5 grade zinc. Steel strip can be hot-dip galvanized in a continuous line, hot-dip galvanized steel strip is extensively used for applications requiring the strength of steel combined with the resistance to corrosion of zinc. Roofing and walling, safety barriers, handrails, consumer appliances, one common use is in metal pails. Other modern techniques have largely replaced hot-dip for these sorts of roles and this includes electrogalvanizing, which deposits the layer of zinc from an aqueous electrolyte by electroplating, forming a thinner and much stronger bond. In 1742, French chemist Paul Jacques Malouin described a method of coating iron by dipping it in molten zinc in a presentation to the French Royal Academy. In 1772 Luigi Galvani, galvanizings namesake, discovered the process that takes place between metals during an experiment with frog legs. In 1801 Alessandro Volta furthered the research on galvanizing when he discovered the electro-potential between two metals, creating a corrosion cell
8.
Aluminium
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Aluminium or aluminum is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal, Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is combined in over 270 different minerals. The chief ore of aluminium is bauxite, Aluminium is remarkable for the metals low density and its ability to resist corrosion through the phenomenon of passivation. Aluminium and its alloys are vital to the industry and important in transportation and structures, such as building facades. The oxides and sulfates are the most useful compounds of aluminium, despite its prevalence in the environment, no known form of life uses aluminium salts metabolically, but aluminium is well tolerated by plants and animals. Because of these salts abundance, the potential for a role for them is of continuing interest. Aluminium is a soft, durable, lightweight, ductile. It is nonmagnetic and does not easily ignite, a fresh film of aluminium serves as a good reflector of visible light and an excellent reflector of medium and far infrared radiation. The yield strength of aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has about one-third the density and stiffness of steel and it is easily machined, cast, drawn and extruded. Aluminium atoms are arranged in a cubic structure. Aluminium has an energy of approximately 200 mJ/m2. Aluminium is a thermal and electrical conductor, having 59% the conductivity of copper. Aluminium is capable of superconductivity, with a critical temperature of 1.2 kelvin. Aluminium is the most common material for the fabrication of superconducting qubits, the strongest aluminium alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This corrosion resistance is reduced by aqueous salts, particularly in the presence of dissimilar metals. In highly acidic solutions, aluminium reacts with water to form hydrogen, primarily because it is corroded by dissolved chlorides, such as common sodium chloride, household plumbing is never made from aluminium
9.
Truss
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In engineering, a truss is a structure that consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object. A two-force member is a component where force is applied to only two points. In this typical context, external forces and reactions to those forces are considered to act only at the nodes and result in forces in the members that are either tensile or compressive. For straight members, moments are explicitly excluded because, and only because, all the joints in a truss are treated as revolutes, as is necessary for the links to be two-force members. A planar truss is one all members and nodes lie within a two dimensional plane, while a space truss has members and nodes that extend into three dimensions. The top beams in a truss are called top chords and are typically in compression, the beams are called bottom chords. The interior beams are called webs, and the areas inside the webs are called panels, Truss derives from the Old French word trousse, from around 1200, which means collection of things bound together. The term truss has often used to describe any assembly of members such as a cruck frame or a couple of rafters. One engineering definition is, A truss is a single plane framework of individual structural member connected at their ends of forms a series of triangle to span a large distance, a truss consists of typically straight members connected at joints, traditionally termed panel points. Trusses are typically composed of triangles because of the stability of that shape. A triangle is the simplest geometric figure that will not change shape when the lengths of the sides are fixed, in comparison, both the angles and the lengths of a four-sided figure must be fixed for it to retain its shape. The joint at which a truss is designed to be supported is commonly referred to as the Munter Point, the simplest form of a truss is one single triangle. This type of truss is seen in a roof consisting of rafters and a ceiling joist. Because of the stability of this shape and the methods of used to calculate the forces within it. The traditional diamond-shape bicycle frame, which utilizes two conjoined triangles, is an example of a simple truss, a planar truss lies in a single plane. Planar trusses are used in parallel to form roofs and bridges. The depth of a truss, or the height between the upper and lower chords, is what makes it an efficient structural form, a solid girder or beam of equal strength would have substantial weight and material cost as compared to a truss. For a given span, a deeper truss will require less material in the chords, an optimum depth of the truss will maximize the efficiency
10.
Agriculture in the United States
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Agriculture is a major industry in the United States, which is a net exporter of food. As of the 2007 census of agriculture, there were 2.2 million farms, covering an area of 922 million acres, an average of 418 acres per farm. The United States was a leader in seed improvement i. e. hybridization and in expanding uses for crops from the work of George Washington Carver to the development of bioplastics, the mechanization of farming and intensive farming have been major themes in U. S. Modern agriculture in the U. S. ranges from the common hobby farms, Corn, turkeys, tomatoes, potatoes, peanuts, and sunflower seeds constitute some of the major holdovers from the agricultural endowment of the Americas. European agricultural practices greatly affected the New England landscape, colonists brought livestock over from Europe which caused many changes to the land. Grazing animals required a lot of land and food and the act of grazing itself destroyed native grasses, New species of weeds were introduced and began to thrive as they were capable of withstanding the grazing of animals, whereas native species could not. The practices associated with keeping livestock also contributed to the deterioration of the forests, colonists would cut down the trees and then allow their cattle and livestock to graze freely in the forest and never plant more trees. The animals trampled and tore up the ground so much as to cause long-term destruction, soil exhaustion was a huge problem in New England agriculture. Farming with oxen did allow the colonist to farm land but it increased erosion. This was due to deeper plow cuts in the soil that allowed the more contact with oxygen causing nutrient depletion. In grazing fields, the number of cattle in the New England, the soil was being compacted by the cattle. In the United States, farms spread from the colonies westward along with the settlers, in cooler regions, wheat was often the crop of choice when lands were newly settled, leading to a wheat frontier that moved westward over the course of years. Also very common in the antebellum Midwest was farming corn while raising hogs, complementing each other especially since it was difficult to get grain to market before the canals, after the wheat frontier had passed through an area, more diversified farms including dairy cattle generally took its place. Warmer regions saw plantings of cotton and herds of beef cattle, in the early colonial south, raising tobacco and cotton was common, especially through the use of slave labor until the Civil War. In the northeast, slaves were used in agriculture until the early 19th century, in the Midwest, slavery was prohibited by the Freedom Ordinance of 1787. The introduction and broad adoption of agriculture since the mid-19th century contributed to economic growth in the United States. Between 1930 and 1942, the United States share of world soybean production skyrocketed from 3% to 46. 5%, by 1973 soybeans were the United States number one cash crop, and leading export commodity, ahead of both wheat and corn. Significant areas of farmland were abandoned during the Great Depression and incorporated into nascent national forests, alfalfa and hay would both be in the top ten in 2003 if they were tracked by FAO
