Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. Geotechnical engineering is important in civil engineering, but has applications in military, mining and other engineering disciplines that are concerned with construction occurring on the surface or within the ground. Geotechnical engineering uses principles of soil mechanics and rock mechanics to investigate subsurface conditions and materials. A typical geotechnical engineering project begins with a review of project needs to define the required material properties. Follows a site investigation of soil, fault distribution and bedrock properties on and below an area of interest to determine their engineering properties including how they will interact with, on or in a proposed construction. Site investigations are needed to gain an understanding of the area in or on which the engineering will take place. Investigations can include the assessment of the risk to humans and the environment from natural hazards such as earthquakes, sinkholes, soil liquefaction, debris flows and rockfalls.
A geotechnical engineer determines and designs the type of foundations, and/or pavement subgrades required for the intended man-made structures to be built. Foundations are designed and constructed for structures of various sizes such as high-rise buildings, medium to large commercial buildings, smaller structures where the soil conditions do not allow code-based design. Foundations built for above-ground structures include deep foundations. Retaining structures include retaining walls. Earthworks include embankments, tunnels and levees, reservoirs, deposition of hazardous waste and sanitary landfills. Geotechnical engineers are extensively involved in earthen and concrete dam projects, evaluating the subsurface conditions at the dam site and the side slopes of the reservoir, the seepage conditions under and around the dam and the stability of the dam under a range of normal and extreme loading conditions. Geotechnical engineering is related to coastal and ocean engineering. Coastal engineering can involve the design and construction of wharves and jetties.
Ocean engineering can involve foundation and anchor systems for offshore structures such as oil platforms. The fields of geotechnical engineering and engineering geology are related, have large areas of overlap. However, the field of geotechnical engineering is a specialty of engineering, where the field of engineering geology is a specialty of geology. Coming from the fields of engineering and science the two may approach the same subject, such as soil classification, with different methods. Humans have used soil as a material for flood control, irrigation purposes, burial sites, building foundations, as construction material for buildings. First activities were linked to irrigation and flood control, as demonstrated by traces of dykes and canals dating back to at least 2000 BCE that were found in ancient Egypt, ancient Mesopotamia and the Fertile Crescent, as well as around the early settlements of Mohenjo Daro and Harappa in the Indus valley; as the cities expanded, structures were erected supported by formalized foundations.
Until the 18th century, however, no theoretical basis for soil design had been developed and the discipline was more of an art than a science, relying on past experience. Several foundation-related engineering problems, such as the Leaning Tower of Pisa, prompted scientists to begin taking a more scientific-based approach to examining the subsurface; the earliest advances occurred in the development of earth pressure theories for the construction of retaining walls. Henri Gautier, a French Royal Engineer, recognized the "natural slope" of different soils in 1717, an idea known as the soil's angle of repose. A rudimentary soil classification system was developed based on a material's unit weight, no longer considered a good indication of soil type; the application of the principles of mechanics to soils was documented as early as 1773 when Charles Coulomb developed improved methods to determine the earth pressures against military ramparts. Coulomb observed that, at failure, a distinct slip plane would form behind a sliding retaining wall and he suggested that the maximum shear stress on the slip plane, for design purposes, was the sum of the soil cohesion, c, friction σ tan , where σ is the normal stress on the slip plane and ϕ is the friction angle of the soil.
By combining Coulomb's theory with Christian Otto Mohr's 2D stress state, the theory became known as Mohr-Coulomb theory. Although it is now recognized that precise determination of cohesion is impossible because c is not a fundamental soil property, the Mohr-Coulomb theory is still used in practice today. In the 19th century Henry Darcy developed what is now known as Darcy's Law describing the flow of fluids in porous media. Joseph Boussinesq developed theories of stress distribution in elastic solids that pr
A litter box, sometimes called a sandbox, litter tray, cat pan, litter pan, or catbox, is an indoor feces and urine collection box for cats, as well as rabbits, miniature pigs, small dogs, other pets that instinctively or through training will make use of such a repository. They are provided for pets that are permitted free roam of a home but who cannot or do not always go outside to excrete their metabolic waste. Many owners of these animals prefer not to let them roam outside for fear that they might succumb to outdoor dangers, such as weather, wildlife, or traffic. A litter box makes it possible to shelter pets from these risks. In the wild, cats excrete in soft or sandy soil for easy burial, they use their paws in a backward sweeping motion to cover their feces. To stimulate this instinctive desire, a litter box's bottom is filled with an inch or more of cat litter. Litter box filler is a granular material that absorbs moisture and odors such as ammonia; some litter brands contain baking soda to absorb such odors.
The litter material satisfies a cat's instinctive desire to use an dug material. The most common material is clay, although recycled paper "pellets" and silica-based "crystal" variants are used. Sometimes, when an owner wishes to stimulate the cat's natural instincts, natural dirt is used. In the US, cat litter is a $2 billion industry consuming five billion pounds of mined clay annually; the first commercially available cat litters in the United States was Kitty Litter, available in 1947 and marketed by Ed Lowe. This was the first large-scale use of clay in litter boxes. Clay litter is much more absorbent than sand and is manufactured into large grains or clumps of clay to make it less to be tracked from the litter box; the brand name Kitty Litter has become a genericized trademark, used by many to denote any type of cat litter. Today, cat litter can be obtained quite economically at a variety of retail stores. Conventional clay litter is indistinguishable from clay-based oil absorbent. Non-clumping cat litter is made of zeolite and sepiolite.
The cat-box that the litter is poured into can give off a strong odor. It is recommended that it is kept in an area in the home, not used, such as a basement or laundry room. There are special types of litter to lessen the odor, they odorized crystals. If kept in room with an intake vent, an air freshener may be added on the furnace filter to isolate the odor from the rest of the house. Litter clumps were first developed in the UK in the 1950s by the Fuller's Earth Union to become a part of Laporte Industries Ltd; the type of clumping litter developed by the FEU was calcium bentonite, a less swelling and less sticky type than American bentonite. Subsequently in America, clumping bentonite was developed in 1984 by biochemist Thomas Nelson. Most are made from granulated bentonite clay which clumps together when wet and forms a solid mass separate from the other litter in the box; this solid clumped material can be scooped out and disposed of without changing the entire contents of the litter box.
Clumping litter also contains quartz or diatomaceous earth. Because of the clumping effect, the manufacturers instruct not to flush clumping litters down the toilet, because it could clog it. Clumping clay cat litters are natural products, they may contain occurring crystalline silica, or silica dust, which in California is treated as a known carcinogen under Proposition 65. Clay litter is criticized by the more expensive manufacturers of non-clay litter as being produced in a strip mine in an environmentally degrading process; this sort of litter can be toxic to ferrets, leading to both digestive problems. Biodegradable litters are made from various plant resources, including pine wood pellets, recycled newspaper, clumping sawdust, Brazilian cassava, wheat, barley, soy pulp and dried orange peel; each year, more than two million tons of cat litter, or 100,000 truckloads, ends up in landfills in the U. S. alone. This is not biodegradable or renewable and adds to the waste burden; some pet owners prefer biodegradable litters due to its friendliness to the environment.
Biodegradable cat litter can be eliminated by safely composting the used litter at home. Other cat owners can be attracted to the biodegradable litters because of their flushability or deodorizing properties. Asthmatic cats may sometimes benefit from the reduced dust in some forms of biodegradable litter. Biodegradable litter packaged for cats tends to be more expensive than traditional clay litters, so cost is not a positive factor in their selection, one of these, namely pine pellets can be purchased from regional feed stores that carry 40 lb bags for horse bedding at a significant cost reduction cheaper than the cheapest clumping litter. Most biodegradable litters last longer than the equivalent size of clay or clumping clay litters. Grain-based animal or poultry feed provides an economical alternative to products marketed as cat litter. Most of these forms of litter are recycled from human usage and are thus reusing a waste product as opposed to drawing clay from mines. Silica gel litter referred to as "crystal litter", is a porous granular form of silicon d
A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers; the well water is drawn by a pump, or using containers, such as buckets, that are raised mechanically or by hand. Wells were first constructed at least eight thousand years ago and vary in construction from a simple scoop in the sediment of a dry watercourse to the qanats of Iran, the stepwells and sakiehs of India. Placing a lining in the well shaft helps create stability, linings of wood or wickerwork date back at least as far as the Iron Age. Wells have traditionally been sunk by hand digging, as is the case in rural areas of the developing world; these wells are inexpensive and low-tech as they use manual labour, the structure can be lined with brick or stone as the excavation proceeds. A more modern method called caissoning uses pre-cast reinforced concrete well rings that are lowered into the hole.
Driven wells can be created in unconsolidated material with a well hole structure, which consists of a hardened drive point and a screen of perforated pipe, after which a pump is installed to collect the water. Deeper wells can be excavated by hand drilling methods or machine drilling, using a bit in a borehole. Drilled wells are cased with a factory-made pipe composed of steel or plastic. Drilled wells can access water at much greater depths than dug wells. Two broad classes of well are shallow or unconfined wells completed within the uppermost saturated aquifer at that location, deep or confined wells, sunk through an impermeable stratum into an aquifer beneath. A collector well can be constructed adjacent to a freshwater lake or stream with water percolating through the intervening material; the site of a well can be selected by a hydrogeologist, or groundwater surveyor. Water may be hand drawn. Impurities from the surface can reach shallow sources and contamination of the supply by pathogens or chemical contaminants needs to be avoided.
Well water contains more minerals in solution than surface water and may require treatment before being potable. Soil salination can occur as the water table falls and the surrounding soil begins to dry out. Another environmental problem is the potential for methane to seep into the water. Wood-lined wells are known from the early Neolithic Linear Pottery culture, for example in Kückhoven, dated 5090 BC and Eythra, dated 5200 BC in Schletz in Austria; some of the earliest evidence of water wells are located in China. The neolithic Chinese made extensive use of deep drilled groundwater for drinking; the Chinese text The Book of Changes a divination text of the Western Zhou dynasty, contains an entry describing how the ancient Chinese maintained their wells and protected their sources of water. Archaeological evidence and old Chinese documents reveal that the prehistoric and ancient Chinese had the aptitude and skills for digging deep water wells for drinking water as early as 6000 to 7000 years ago.
A well excavated at the Hemedu excavation site was believed to have been built during the neolithic era. The well was cased by four rows of logs with a square frame attached to them at the top of the well. 60 additional tile wells southwest of Beijing are believed to have been built around 600 BC for drinking and irrigation. In Egypt and sakiehs are used; when compared to each other however, the Sakkieh is much more efficient, as it can bring up water from a depth of 10 metres. The Sakieh is the Egyptian version of the Noria; some of the world's oldest known wells, located in Cyprus, date to 7000-8500 BC. Two wells from the Neolithic period, around 6500 BC, have been discovered in Israel. One is in Atlit, on the northern coast of Israel, the other is the Jezreel Valley. Wells for other purposes came along much historically; the first recorded salt well was dug in the Sichuan province of China around 2,250 years ago. This was the first time that ancient water well technology was applied for the exploitation of salt, marked the beginning of Sichuan’s salt drilling industry.
The earliest known oil wells were drilled in China, in 347 CE. These wells had depths of up to about 240 metres and were drilled using bits attached to bamboo poles; the oil was burned to produce salt. By the 10th century, extensive bamboo pipelines connected oil wells with salt springs; the ancient records of China and Japan are said to contain many allusions to the use of natural gas for lighting and heating. Petroleum was known as Burning water in Japan in the 7th century; until recent centuries, all artificial wells were pumpless hand-dug wells of varying degrees of sophistication, they remain a important source of potable water in some rural developing areas where they are dug and used today. Their indispensability has produced a number of literary references and figurative, to them, including the reference to the incident of Jesus meeting a woman at Jacob's well in the bible and the "Ding Dong Bell" nursery rhyme about a cat in a well. Hand-dug wells are excavations with diameters large enough to accommodate one or more people with shovels digging down to below the water table.
The excavation is braced horizontally to avoid erosion endangering the people digging. They can be lined with brick. A more modern method called caissoning
Potassium is a chemical element with symbol K and atomic number 19. It was first isolated from the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals. All of the alkali metals have a single valence electron in the outer electron shell, removed to create an ion with a positive charge – a cation, which combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium is a soft silvery-white alkali metal that oxidizes in air and reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, burning with a lilac-colored flame, it is found dissolved in sea water, is part of many minerals. Potassium is chemically similar to sodium, the previous element in group 1 of the periodic table, they have a similar first ionization energy, which allows for each atom to give up its sole outer electron. That they are different elements that combine with the same anions to make similar salts was suspected in 1702, was proven in 1807 using electrolysis.
Occurring potassium is composed of three isotopes, of which 40K is radioactive. Traces of 40K are found in all potassium, it is the most common radioisotope in the human body. Potassium ions are vital for the functioning of all living cells; the transfer of potassium ions across nerve cell membranes is necessary for normal nerve transmission. Fresh fruits and vegetables are good dietary sources of potassium; the body responds to the influx of dietary potassium, which raises serum potassium levels, with a shift of potassium from outside to inside cells and an increase in potassium excretion by the kidneys. Most industrial applications of potassium exploit the high solubility in water of potassium compounds, such as potassium soaps. Heavy crop production depletes the soil of potassium, this can be remedied with agricultural fertilizers containing potassium, accounting for 95% of global potassium chemical production; the English name for the element potassium comes from the word "potash", which refers to an early method of extracting various potassium salts: placing in a pot the ash of burnt wood or tree leaves, adding water and evaporating the solution.
When Humphry Davy first isolated the pure element using electrolysis in 1807, he named it potassium, which he derived from the word potash. The symbol "K" stems from kali, itself from the root word alkali, which in turn comes from Arabic: القَلْيَه al-qalyah "plant ashes". In 1797, the German chemist Martin Klaproth discovered "potash" in the minerals leucite and lepidolite, realized that "potash" was not a product of plant growth but contained a new element, which he proposed to call kali. In 1807, Humphry Davy produced the element via electrolysis: in 1809, Ludwig Wilhelm Gilbert proposed the name Kalium for Davy's "potassium". In 1814, the Swedish chemist Berzelius advocated the name kalium for potassium, with the chemical symbol "K"; the English and French speaking countries adopted Davy and Gay-Lussac/Thénard's name Potassium, while the Germanic countries adopted Gilbert/Klaproth's name Kalium. The "Gold Book" of the International Union of Physical and Applied Chemistry has designated the official chemical symbol as K.
Potassium is the second least dense metal after lithium. It is a soft solid with a low melting point, can be cut with a knife. Freshly cut potassium is silvery in appearance, but it begins to tarnish toward gray on exposure to air. In a flame test and its compounds emit a lilac color with a peak emission wavelength of 766.5 nanometers. Neutral potassium atoms have 19 electrons, one more than the stable configuration of the noble gas argon; because of this and its low first ionization energy of 418.8 kJ/mol, the potassium atom is much more to lose the last electron and acquire a positive charge than to gain one and acquire a negative charge. This process requires so little energy that potassium is oxidized by atmospheric oxygen. In contrast, the second ionization energy is high, because removal of two electrons breaks the stable noble gas electronic configuration. Potassium therefore does not form compounds with the oxidation state of higher. Potassium is an active metal that reacts violently with oxygen in water and air.
With oxygen it forms potassium peroxide, with water potassium forms potassium hydroxide. The reaction of potassium with water is dangerous because of its violent exothermic character and the production of hydrogen gas. Hydrogen reacts again with atmospheric oxygen, producing water, which reacts with the remaining potassium; this reaction requires only traces of water. Because of the sensitivity of potassium to water and air, reactions with other elements are possible only in an inert atmosphere such as argon gas using air-free techniques. Potassium does not react with most hydrocarbons such as mineral kerosene, it dissolves in liquid ammonia, up to 480 g per 1000 g of ammonia at 0 °C. Depending on the concentration, the ammonia solutions are blue to yellow, their electrical conductivity is similar to that of liquid metals. In a pure solution, potassium reacts with ammonia to form KNH2, but this reaction is accelerated by minute amounts of transition metal s
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is carbon with variable amounts of other elements. Coal is formed if dead plant matter decays into peat and over millions of years the heat and pressure of deep burial converts the peat into coal. Vast deposits of coal originates in former wetlands—called coal forests—that covered much of the Earth's tropical land areas during the late Carboniferous and Permian times; as a fossil fuel burned for heat, coal supplies about a quarter of the world's primary energy and two-fifths of its electricity. Some iron and steel making and other industrial processes burn coal; the extraction and use of coal causes much illness. Coal damages the environment, including by climate change as it is the largest anthropogenic source of carbon dioxide, 14 Gt in 2016, 40% of the total fossil fuel emissions; as part of the worldwide energy transition many countries use less coal. The largest consumer and importer of coal is China.
China mines account for half the world's coal, followed by India with about a tenth. Australia accounts for about a third of world coal exports followed by Russia; the word took the form col in Old English, from Proto-Germanic *kula, which in turn is hypothesized to come from the Proto-Indo-European root *gu-lo- "live coal". Germanic cognates include the Old Frisian kole, Middle Dutch cole, Dutch kool, Old High German chol, German Kohle and Old Norse kol, the Irish word gual is a cognate via the Indo-European root. Coal is composed of macerals and water. Fossils and amber may be found in coal. At various times in the geologic past, the Earth had dense forests in low-lying wetland areas. Due to natural processes such as flooding, these forests were buried underneath soil; as more and more soil deposited over them, they were compressed. The temperature rose as they sank deeper and deeper; as the process continued the plant matter was protected from biodegradation and oxidation by mud or acidic water.
This trapped the carbon in immense peat bogs that were covered and buried by sediments. Under high pressure and high temperature, dead vegetation was converted to coal; the conversion of dead vegetation into coal is called coalification. Coalification starts with dead plant matter decaying into peat. Over millions of years the heat and pressure of deep burial causes the loss of water and carbon dioxide and an increase in the proportion of carbon, thus first lignite sub-bituminous coal, bituminous coal, lastly anthracite may be formed. The wide, shallow seas of the Carboniferous Period provided ideal conditions for coal formation, although coal is known from most geological periods; the exception is the coal gap in the Permian -- Triassic extinction event. Coal is known from Precambrian strata, which predate land plants—this coal is presumed to have originated from residues of algae. Sometimes coal seams are interbedded with other sediments in a cyclothem; as geological processes apply pressure to dead biotic material over time, under suitable conditions, its metamorphic grade or rank increases successively into: Peat, a precursor of coal Lignite, or brown coal, the lowest rank of coal, most harmful to health, used exclusively as fuel for electric power generation Jet, a compact form of lignite, sometimes polished.
Bituminous coal, a dense sedimentary rock black, but sometimes dark brown with well-defined bands of bright and dull material It is used as fuel in steam-electric power generation and to make coke. Anthracite, the highest rank of coal is a harder, glossy black coal used for residential and commercial space heating. Graphite is difficult to ignite and not used as fuel. Cannel coal is a variety of fine-grained, high-rank coal with significant hydrogen content, which consists of liptinite. There are several international standards for coal; the classification of coal is based on the content of volatiles. However the most important distinction is between thermal coal, burnt to generate electricity via steam. Hilt's law is a geological observation, the higher its rank, it applies if the thermal gradient is vertical. The earliest recognized use is from the Shenyang area of China where by 4000 BC Neolithic inhabitants had begun carving ornaments from black lignite. Coal from the Fushun mine in northeastern China was used to smelt copper as early as 1000 BC.
Marco Polo, the Italian who traveled to China in the 13th century, described coal as "black stones... which burn like logs", said coal was so plentiful, people could take three hot baths a week. In Europe, the earliest reference to the use of coal as fuel is from the geological treatise On stones by the Greek scientist Theophrastus: Among the materials that are dug because they are useful, those known as anthrakes are made of earth, once set on fire, they burn like charcoa
Volcanic ash consists of fragments of pulverized rock and volcanic glass, created during volcanic eruptions and measuring less than 2 mm in diameter. The term volcanic ash is often loosely used to refer to all explosive eruption products, including particles larger than 2 mm. Volcanic ash is formed during explosive volcanic eruptions when dissolved gases in magma expand and escape violently into the atmosphere; the force of the escaping gas shatters the magma and propels it into the atmosphere where it solidifies into fragments of volcanic rock and glass. Ash is produced when magma comes into contact with water during phreatomagmatic eruptions, causing the water to explosively flash to steam leading to shattering of magma. Once in the air, ash is transported by wind up to thousands of kilometers away. Due to its wide dispersal, ash can have a number of impacts on society, including human and animal health, disruption to aviation, disruption to critical infrastructure, primary industries and structures.
Volcanic ash is formed during explosive volcanic eruptions, phreatomagmatic eruptions and during transport in pyroclastic density currents. Explosive eruptions occur when magma decompresses as it rises, allowing dissolved volatiles to exsolve into gas bubbles; as more bubbles nucleate a foam is produced, which decreases the density of the magma, accelerating it up the conduit. Fragmentation occurs; when fragmentation occurs, violently expanding bubbles tear the magma apart into fragments which are ejected into the atmosphere where they solidify into ash particles. Fragmentation is a efficient process of ash formation and is capable of generating fine ash without the addition of water. Volcanic ash is produced during phreatomagmatic eruptions. During these eruptions fragmentation occurs when magma comes into contact with bodies of water groundwater, snow or ice; as the magma, hotter than the boiling point of water, comes into contact with water an insulating vapor film forms. This vapor film will collapse leading to direct coupling of the cold water and hot magma.
This increases the heat transfer which leads to the rapid expansion of water and fragmentation of the magma into small particles which are subsequently ejected from the volcanic vent. Fragmentation causes an increase in contact area between magma and water creating a feedback mechanism, leading to further fragmentation and production of fine ash particles. Pyroclastic density currents can produce ash particles; these are produced by lava dome collapse or collapse of the eruption column. Within pyroclastic density currents particle abrasion occurs as particles interact with each other resulting in a reduction in grain size and production of fine grained ash particles. In addition, ash can be produced during secondary fragmentation of pumice fragments, due to the conservation of heat within the flow; these processes produce large quantities of fine grained ash, removed from pyroclastic density currents in co-ignimbrite ash plumes. Physical and chemical characteristics of volcanic ash are controlled by the style of volcanic eruption.
Volcanoes display a range of eruption styles which are controlled by magma chemistry, crystal content and dissolved gases of the erupting magma and can be classified using the volcanic explosivity index. Effusive eruptions of basaltic composition produce <105 m3 of ejecta, whereas explosive eruptions of rhyolitic and dacitic composition can inject large quantities of ejecta into the atmosphere. Another parameter controlling the amount of ash produced is the duration of the eruption: the longer the eruption is sustained, the more ash will be produced. For example, the second phase of the 2010 eruptions of Eyjafjallajökull was classified as VEI 4 despite a modest 8 km high eruption column, but the eruption continued for a month, which allowed a large volume of ash to be ejected into the atmosphere; the types of minerals present in volcanic ash are dependent on the chemistry of the magma from which it erupted. Considering that the most abundant elements found in silicate magma are silicon and oxygen, the various types of magma produced during volcanic eruptions are most explained in terms of their silica content.
Low energy eruptions of basalt produce a characteristically dark coloured ash containing ~45 - 55% silica, rich in iron and magnesium. The most explosive rhyolite eruptions produce a felsic ash, high in silica while other types of ash with an intermediate composition have a silica content between 55-69%; the principal gases released during volcanic activity are water, carbon dioxide, sulfur dioxide, hydrogen sulfide, carbon monoxide and hydrogen chloride. These sulfur and halogen gases and metals are removed from the atmosphere by processes of chemical reaction and wet deposition, by adsorption onto the surface of volcanic ash, it has long been recognised that a range of sulfate and halide compounds are mobilised from fresh volcanic ash.. While some 55 ionic species have been reported in fresh ash leachates the most
An oil is any nonpolar chemical substance, a viscous liquid at ambient temperatures and is both hydrophobic and lipophilic. Oils have a high carbon and hydrogen content and are flammable and surface active; the general definition of oil includes classes of chemical compounds that may be otherwise unrelated in structure and uses. Oils may be animal, vegetable, or petrochemical in origin, may be volatile or non-volatile, they are used for food, medical purposes and the manufacture of many types of paints and other materials. Specially prepared oils are used in some religious rituals as purifying agents. First attested in English 1176, the word oil comes from Old French oile, from Latin oleum, which in turn comes from the Greek ἔλαιον, "olive oil, oil" and that from ἐλαία, "olive tree", "olive fruit"; the earliest attested forms of the word are the Mycenaean Greek, e-ra-wo and, e-rai-wo, written in the Linear B syllabic script. Organic oils are produced in remarkable diversity by plants and other organisms through natural metabolic processes.
Lipid is the scientific term for the fatty acids and similar chemicals found in the oils produced by living things, while oil refers to an overall mixture of chemicals. Organic oils may contain chemicals other than lipids, including proteins and alkaloids. Lipids can be classified by the way that they are made by an organism, their chemical structure and their limited solubility in water compared to oils, they have a high carbon and hydrogen content and are lacking in oxygen compared to other organic compounds and minerals. Crude oil, or petroleum, its refined components, collectively termed petrochemicals, are crucial resources in the modern economy. Crude oil originates from ancient fossilized organic materials, such as zooplankton and algae, which geochemical processes convert into oil; the name "mineral oil" is a misnomer, in that minerals are not the source of the oil—ancient plants and animals are. Mineral oil is organic. However, it is classified as "mineral oil" instead of as "organic oil" because its organic origin is remote, because it is obtained in the vicinity of rocks, underground traps, sands.
Mineral oil refers to several specific distillates of crude oil. Several edible vegetable and animal oils, fats, are used for various purposes in cooking and food preparation. In particular, many foods are fried in oil much hotter than boiling water. Oils are used for flavoring and for modifying the texture of foods. Cooking oils are derived either from animal fat, as butter and other types, or plant oils from the olive, maize and many other species. Oils are applied to hair to give it a lustrous look, to prevent tangles and roughness and to stabilize the hair to promote growth. See hair conditioner. Oil has been used throughout history as a religious medium, it is considered a spiritually purifying agent and is used for anointing purposes. As a particular example, holy anointing oil has been an important ritual liquid for Judaism and Christianity. Color pigments are suspended in oil, making it suitable as a supporting medium for paints; the oldest known extant oil paintings date from 650 AD. Oils are used for instance in electric transformers.
Heat transfer oils are used both as coolants, for heating and in other applications of heat transfer. Given that they are non-polar, oils do not adhere to other substances; this makes them useful as lubricants for various engineering purposes. Mineral oils are more used as machine lubricants than biological oils are. Whale oil is preferred for lubricating clocks, because it does not evaporate, leaving dust, although its use was banned in the USA in 1980, it is a long-running myth that spermaceti from whales has still been used in NASA projects such as the Hubble Telescope and the Voyager probe because of its low freezing temperature. Spermaceti is not an oil, but a mixture of wax esters, there is no evidence that NASA has used whale oil; some oils burn in liquid or aerosol form, generating light, heat which can be used directly or converted into other forms of energy such as electricity or mechanical work. To obtain many fuel oils, crude oil is pumped from the ground and is shipped via oil tanker or a pipeline to an oil refinery.
There, it is converted from crude oil to diesel fuel, fuel oils, jet fuel, kerosene and liquefied petroleum gas. A 42-US-gallon barrel of crude oil produces 10 US gallons of diesel, 4 US gallons of jet fuel, 19 US gallons of gasoline, 7 US gallons of other products, 3 US gallons split between heavy fuel oil and liquified petroleum gases, 2 US gallons of heating oil; the total production of a barrel of crude into various products results in an increase to 45 US gallons. Not all oils used as fuels are mineral oils, see biodiesel and vegetable oil fuel. In the 18th and 19th cent