A silo is a structure for storing bulk materials. Silos are used in agriculture to store grain or fermented feed known as silage. Silos are more used for bulk storage of grain, cement, carbon black, food products and sawdust. Three types of silos are in widespread use today: tower silos, bunker silos, bag silos. There are different types of cement silos such as the low-level mobile silo and the static upright cement silo, which are used to hold and discharge cement and other powder materials such as PFA; the low-level silos are mobile with capacities from 100 to 750 tons. They are easy to set up on site; these mobile silos come equipped with an electronic weighing system with digital display and printer. This allows any quantity of cement or powder discharged from the silo to be controlled and provides an accurate indication of what remains inside the silo; the static upright silos have capacities from 200 to 800 tons. These are considered a low-maintenance option for the storage of cement or other powders.
Cement silos can be used in conjunction with bin-fed batching plants. Cement can be stored in different types of Silos like Horizontal Mobile Silos, Concrete Silos, Steel Panel Silos etc. depending upon the requirement of the end user. While Mobile Silos come in a small storage capacity of 90MT of Cement, Concrete Silos can store thousands of MT of Cement. A majority of Silos that store more than 5000 MT of Cement are constructed from Concrete. A good compromise between cost, construction time and ease of operation is Steel Panel Silos; these silos can be manufactured in a factory, erected at site using small panels that are bolted together to form a Silo, watertight because of a sandwiched layer of special rubber seals. Storage silos are cylindrical structures 10 to 90 ft in diameter and 30 to 275 ft in height with the slipform and Jumpform concrete silos being the larger diameter and taller silos, they can be made of many materials. Wood staves, concrete staves, cast concrete, steel panels have all been used, have varying cost and airtightness tradeoffs.
Silos storing grain and woodchips are unloaded with air slides or augers. Silos can be unloaded into trucks or conveyors. Tower silos containing silage are unloaded from the top of the pile by hand using a silage fork, which has many more tines than the common pitchfork, 12 vs 4, in modern times using mechanical unloaders. Bottom silo unloaders have problems with difficulty of repair. An advantage of tower silos is that the silage tends to pack well due to its own weight, except in the top few feet. However, this may be a disadvantage for items like chopped wood; the tower silo was invented by Franklin Hiram King. In Canada and the United States, many country towns or the larger farmers in grain-growing areas have groups of wooden or concrete tower silos, known as grain elevators, to collect grain from the surrounding towns and store and protect the grain for transport by train, truck or barge to a processor or to an export port. In bumper crop times, the excess grain is stored in piles without silos or bins, causing considerable losses.
Concrete stave silos are constructed from small precast concrete blocks with ridged grooves along each edge that lock them together into a high strength shell. Concrete is much stronger in compression than tension, so the silo is reinforced with steel hoops encircling the tower and compressing the staves into a tight ring; the vertical stacks are held together by intermeshing of the ends of the staves by a short distance around the perimeter of each layer, hoops which are tightened directly across the stave edges. The static pressure of the material inside the silo pressing outward on the staves increases towards the bottom of the silo, so the hoops can be spaced wide apart near the top but become progressively more spaced towards the bottom to prevent seams from opening and the contents leaking out. Concrete stave silos are built from common components designed for long life, they have the flexibility to have their height increased according to the needs of the farm and purchasing power of the farmer, or to be disassembled and reinstalled somewhere else if no longer needed.
Low-oxygen silos are designed to keep the contents in a low-oxygen atmosphere at all times, to keep the fermented contents in a high quality state, to prevent mold and decay, as may occur in the top layers of a stave silo or bunker. Low-oxygen silos are only opened directly to the atmosphere during the initial forage loading, the unloader chute is sealed against air infiltration, it would be expensive to design such a large structure, immune to atmospheric pressure changes over time. Instead, the silo structure is open to the atmosphere but outside air is separated from internal air by large impermeable bags sealed to the silo breather openings. In the warmth of the day when the silo is heated by the sun, the gas trapped inside the silo expands and the bags "breathe out" and collapse. At night the silo cools, the air inside contracts and the bags expand again. While the iconic blue Harvestore low-oxygen silos were once common, the speed of its unloader mechanism was not able to match the output rates of modern bunker silos, this type of silo went into decline.
Unloader repair expenses severely hurt the Harvestore reputation, because the unloader feed mechanism is located in the bottom of the silo under tons of silage. In the event of cutter chain breakage, it can c
A petroleum reservoir or oil and gas reservoir is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. Petroleum reservoirs are broadly classified as unconventional reservoirs. In case of conventional reservoirs, the occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability. While in unconventional reservoirs the rocks have high porosity and low permeability which keeps the hydrocarbons trapped in place, therefore not requiring a cap rock. Reservoirs are found using hydrocarbon exploration methods. A region with an abundance of oil wells extracting petroleum from below ground; because the oil reservoirs extend over a large area several hundred kilometres across, full exploitation entails multiple wells scattered across the area. In addition, there may be exploratory wells probing the edges, pipelines to transport the oil elsewhere, support facilities; because an oil field may be remote from civilization, establishing a field is an complicated exercise in logistics.
This goes beyond requirements for drilling. For instance, workers require housing to allow them to work onsite for years. In turn and equipment require electricity and water. In cold regions, pipelines may need to be heated. Excess natural gas may be burned off if there is no way to make use of it—which requires a furnace and pipes to carry it from the well to the furnace. Thus, the typical oil field resembles a small, self-contained town in the midst of a landscape dotted with drilling rigs or the pump jacks, which are known as "nodding donkeys" because of their bobbing arm. Several companies, such as Hill International, Esso, Weatherford International, Schlumberger Limited, Baker Hughes and Halliburton, have organizations that specialize in the large-scale construction of the infrastructure and providing specialized services required to operate a field profitably. More than 40,000 oil fields are scattered around the globe, on land and offshore; the largest are the Ghawar Field in Saudi Arabia and the Burgan Field in Kuwait, with more than 60 billion barrels estimated in each.
Most oil fields are much smaller. According to the US Department of Energy, as of 2003 the US alone had over 30,000 oil fields. In the modern age, the location of oil fields with proven oil reserves is a key underlying factor in many geopolitical conflicts; the term "oilfield" is used as a shorthand to refer to the entire petroleum industry. However, it is more accurate to divide the oil industry into three sectors: upstream and downstream. Natural gas originates by the same geological thermal cracking process that converts kerogen to petroleum; as a consequence and natural gas are found together. In common usage, deposits rich in oil are known as oil fields, deposits rich in natural gas are called natural gas fields. In general, organic sediments buried in depths of 1,000 m to 6,000 m generate oil, while sediments buried deeper and at higher temperatures generate natural gas; the deeper the source, the "drier" the gas. Because both oil and natural gas are lighter than water, they tend to rise from their sources until they either seep to the surface or are trapped by a non-permeable stratigraphic trap.
They can be extracted from the trap by drilling. The largest natural gas field is South Pars/Asalouyeh gas field, shared between Iran and Qatar; the second largest natural gas field is the Urengoy gas field, the third largest is the Yamburg gas field, both in Russia. Like oil, natural gas is found underwater in offshore gas fields such as the North Sea, Corrib Gas Field off Ireland, near Sable Island; the technology to extract and transport offshore natural gas is different from land-based fields. It uses a few large offshore drilling rigs, due to the cost and logistical difficulties in working over water. Rising gas prices in the early 21st century encouraged drillers to revisit fields that were not considered economically viable. For example, in 2008 McMoran Exploration passed a drilling depth of over 32,000 feet at the Blackbeard site in the Gulf of Mexico. Exxon Mobil's drill rig there had reached 30,000 feet by 2006 without finding gas, before it abandoned the site. Crude oil is found in all oil reservoirs formed in the Earth's crust from the remains of once-living things.
Evidence indicates that millions of years of heat and pressure changed the remains of microscopic plant and animal into oil and natural gas. Roy Nurmi, an interpretation adviser for Schlumberger oil field services company, described the process as follows: Plankton and algae and the life that's floating in the sea, as it dies, falls to the bottom, these organisms are going to be the source of our oil and gas; when they're buried with the accumulating sediment and reach an adequate temperature, something above 50 to 70 °C they start to cook. This transformation, this change, changes them into the liquid hydrocarbons that move and migrate, will become our oil and gas reservoir. In addition to the aquatic environment, a sea, but might be a river, coral reef or algal mat, the formation of an oil or gas reservoir requires a sedimentary basin that passes through four steps: Deep burial under sand and mud. Pressure cooking. Hydrocarbon migration from the sou
Sediment is a occurring material, broken down by processes of weathering and erosion, is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation and if buried, may become sandstone and siltstone. Sediments are most transported by water, but wind and glaciers. Beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian deposition. Glacial moraine deposits and till are ice-transported sediments. Sediment can be classified based on its grain composition. Sediment size is measured on a log base 2 scale, called the "Phi" scale, which classifies particles by size from "colloid" to "boulder". Composition of sediment can be measured in terms of: parent rock lithology mineral composition chemical make-up.
This leads to an ambiguity in which clay can be used as a composition. Sediment is transported based on the strength of the flow that carries it and its own size, volume and shape. Stronger flows will increase the lift and drag on the particle, causing it to rise, while larger or denser particles will be more to fall through the flow. Rivers and streams carry sediment in their flows; this sediment can be in a variety of locations within the flow, depending on the balance between the upwards velocity on the particle, the settling velocity of the particle. These relationships are shown in the following table for the Rouse number, a ratio of sediment fall velocity to upwards velocity. Rouse = Settling velocity Upwards velocity from lift and drag = w s κ u ∗ where w s is the fall velocity κ is the von Kármán constant u ∗ is the shear velocity If the upwards velocity is equal to the settling velocity, sediment will be transported downstream as suspended load. If the upwards velocity is much less than the settling velocity, but still high enough for the sediment to move, it will move along the bed as bed load by rolling and saltating.
If the upwards velocity is higher than the settling velocity, the sediment will be transported high in the flow as wash load. As there are a range of different particle sizes in the flow, it is common for material of different sizes to move through all areas of the flow for given stream conditions. Sediment motion can create self-organized structures such as ripples, dunes, or antidunes on the river or stream bed; these bedforms are preserved in sedimentary rocks and can be used to estimate the direction and magnitude of the flow that deposited the sediment. Overland flow can transport them downslope; the erosion associated with overland flow may occur through different methods depending on meteorological and flow conditions. If the initial impact of rain droplets dislodges soil, the phenomenon is called rainsplash erosion. If overland flow is directly responsible for sediment entrainment but does not form gullies, it is called "sheet erosion". If the flow and the substrate permit channelization, gullies may form.
The major fluvial environments for deposition of sediments include: Deltas Point bars Alluvial fans Braided rivers Oxbow lakes Levees Waterfalls Wind results in the transportation of fine sediment and the formation of sand dune fields and soils from airborne dust. Glaciers carry a wide range of sediment sizes, deposit it in moraines; the overall balance between sediment in transport and sediment being deposited on the bed is given by the Exner equation. This expression states that the rate of increase in bed elevation due to deposition is proportional to the amount of sediment that falls out of the flow; this equation is important in that changes in the power of the flow change the ability of the flow to carry sediment, this is reflected in the patterns of erosion and deposition observed throughout a stream. This can be localized, due to small obstacles. Erosion and deposition can be regional. Deposition can occur due to dam emplacement that causes the river to pool and deposit its entire load, or due to base level rise.
Seas and lakes accumulate sediment over time. The sediment can consist of terrigenous material, which originates on land, but may be deposited in either terrestrial, marine, or lacustrine environments, or of sediments originating in the body of water. Terrigenous material is supplied by nearby rivers and streams or reworked marine sediment. In the mid-ocean, the exoskeletons of dead organisms are responsible for sediment accumulation. Deposited sediments are the source of sedimentary rocks, which can contain fossils of
Louisiana is a state in the Deep South region of the South Central United States. It is the 25th most populous of the 50 United States. Louisiana is bordered by the state of Texas to the west, Arkansas to the north, Mississippi to the east, the Gulf of Mexico to the south. A large part of its eastern boundary is demarcated by the Mississippi River. Louisiana is the only U. S. state with political subdivisions termed parishes. The state's capital is Baton Rouge, its largest city is New Orleans. Much of the state's lands were formed from sediment washed down the Mississippi River, leaving enormous deltas and vast areas of coastal marsh and swamp; these contain a rich southern biota. There are many species of tree frogs, fish such as sturgeon and paddlefish. In more elevated areas, fire is a natural process in the landscape, has produced extensive areas of longleaf pine forest and wet savannas; these support an exceptionally large number of plant species, including many species of terrestrial orchids and carnivorous plants.
Louisiana has more Native American tribes than any other southern state, including four that are federally recognized, ten that are state recognized, four that have not received recognition. Some Louisiana urban environments have a multicultural, multilingual heritage, being so influenced by a mixture of 18th-century French, Spanish, Native American, African cultures that they are considered to be exceptional in the US. Before the American purchase of the territory in 1803, present-day Louisiana State had been both a French colony and for a brief period a Spanish one. In addition, colonists imported numerous African people as slaves in the 18th century. Many came from peoples of the same region of West Africa. In the post-Civil War environment, Anglo-Americans increased the pressure for Anglicization, in 1921, English was for a time made the sole language of instruction in Louisiana schools before a policy of multilingualism was revived in 1974. There has never been an official language in Louisiana, the state constitution enumerates "the right of the people to preserve and promote their respective historic and cultural origins."
Louisiana was named after Louis XIV, King of France from 1643 to 1715. When René-Robert Cavelier, Sieur de La Salle claimed the territory drained by the Mississippi River for France, he named it La Louisiane; the suffix -ana is a Latin suffix that can refer to "information relating to a particular individual, subject, or place." Thus Louis + ana carries the idea of "related to Louis." Once part of the French Colonial Empire, the Louisiana Territory stretched from present-day Mobile Bay to just north of the present-day Canada–United States border, including a small part of what is now the Canadian provinces of Alberta and Saskatchewan. The Gulf of Mexico did not exist 250 million years ago when there was but one supercontinent, Pangea; as Pangea split apart, the Atlantic Ocean and Gulf of Mexico opened. Louisiana developed, over millions of years, from water into land, from north to south; the oldest rocks are exposed in areas such as the Kisatchie National Forest. The oldest rocks date back to the early Cenozoic Era, some 60 million years ago.
The history of the formation of these rocks can be found in D. Spearing's Roadside Geology of Louisiana; the youngest parts of the state were formed during the last 12,000 years as successive deltas of the Mississippi River: the Maringouin, Teche, St. Bernard, the modern Mississippi, now the Atchafalaya; the sediments were carried from north to south by the Mississippi River. In between the Tertiary rocks of the north, the new sediments along the coast, is a vast belt known as the Pleistocene Terraces, their age and distribution can be related to the rise and fall of sea levels during past ice ages. In general, the northern terraces have had sufficient time for rivers to cut deep channels, while the newer terraces tend to be much flatter. Salt domes are found in Louisiana, their origin can be traced back to the early Gulf of Mexico, when the shallow ocean had high rates of evaporation. There are several hundred salt domes in the state. Salt domes are important not only as a source of salt. Louisiana is bordered to the west by Texas.
The state may properly be divided into two parts, the uplands of the north, the alluvial along the coast. The alluvial region includes low swamp lands, coastal marshlands and beaches, barrier islands that cover about 20,000 square miles; this area lies principally along the Gulf of Mexico and the Mississippi River, which traverses the state from north to south for a distance of about 600 mi ) and empties into the Gulf of Mexico. The breadth of the alluvial region along the Mississippi is from 10 to 60 miles, along the other rivers, the alluvial region averages about 10 miles across; the Mississippi River flows along a ridge formed by its own natural deposits, from which the lands decline toward a river beyond at an average fall of six feet per mile. The alluvial lands along other streams present similar features; the higher and contiguous hill lands of the north and northwestern part of the state have an area of more than 25,000 square miles. They consist of prairie and woodl
Halite known as rock salt, is a type of salt, the mineral form of sodium chloride. Halite forms isometric crystals; the mineral is colorless or white, but may be light blue, dark blue, pink, orange, yellow or gray depending on inclusion of other materials and structural or isotopic abnormalities in the crystals. It occurs with other evaporite deposit minerals such as several of the sulfates and borates; the name halite is derived from the Ancient Greek word for salt, ἅλς. Halite occurs in vast beds of sedimentary evaporite minerals that result from the drying up of enclosed lakes and seas. Salt beds may underlie broad areas. In the United States and Canada extensive underground beds extend from the Appalachian basin of western New York through parts of Ontario and under much of the Michigan Basin. Other deposits are in Ohio, New Mexico, Nova Scotia and Saskatchewan; the Khewra salt mine is a massive deposit of halite near Pakistan. Salt domes are vertical diapirs or pipe-like masses of salt that have been "squeezed up" from underlying salt beds by mobilization due to the weight of overlying rock.
Salt domes contain anhydrite and native sulfur, in addition to halite and sylvite. They are common along the Gulf coasts of Texas and Louisiana and are associated with petroleum deposits. Germany, the Netherlands and Iran have salt domes. Salt glaciers exist in arid Iran where the salt has broken through the surface at high elevation and flows downhill. In all of these cases, halite is said to be behaving in the manner of a rheid. Unusual, fibrous vein filling halite is found in France and a few other localities. Halite crystals termed hopper crystals appear to be "skeletons" of the typical cubes, with the edges present and stairstep depressions on, or rather in, each crystal face. In a crystallizing environment, the edges of the cubes grow faster than the centers. Halite crystals form quickly in some evaporating lakes resulting in modern artifacts with a coating or encrustation of halite crystals. Halite flowers are rare stalactites of curling fibers of halite that are found in certain arid caves of Australia's Nullarbor Plain.
Halite stalactites and encrustations are reported in the Quincy native copper mine of Hancock, Michigan. The worlds largest underground salt mine is the Sifto Salt Mine, it uses the Room and Pillar Mining Method. It is located half a kilometre under Lake Huron in Canada. In the United Kingdom there are three mines. Salt is used extensively in cooking as a flavor enhancer, to cure a wide variety of foods such as bacon and fish, it is used in food preservation methods across various cultures. Larger pieces dusted over food from a shaker as finishing salt. Halite is often used both residentially and municipally for managing ice; because brine has a lower freezing point than pure water, putting salt or saltwater on ice, below 0 °C will cause it to melt. It is common for homeowners in cold climates to spread salt on their sidewalks and driveways after a snow storm to melt the ice, it is not necessary to use so much salt that the ice is melted. Many cities will spread a mixture of sand and salt on roads during and after a snowstorm to improve traction.
Using Salt Brine is more effective than spreading dry salt because moisture is necessary for the freezing-point depression to work and wet salt sticks to the roads better. Otherwise the salt can be wiped away by traffic. In addition to de-icing, rock salt is used in agriculture. An example of this would be inducing salt stress to suppress the growth of annual meadow grass in turf production. Other examples involve exposing weeds to salt water to dehydrate and kill them preventing them from affecting other plants. Salt is used as a household cleaning product, its coarse nature allows for its use in various cleaning scenarios including grease/oil removal, stain removal, dries out and hardens sticky spills for an easier clean. Some cultures in Africa and Brazil, prefer a wide variety of different rock salts for different dishes. Pure salt is avoided. Many recipes call for particular kinds of rock salt, imported pure salt has impurities added to adapt to local tastes. Salt was used as a form of currency in barter systems and was exlcusively controlled by authorities and their appointees.
In some ancient civilizations the practice of Salting The Earth was done to make conquered land of an enemy infertile and inhospitable as an act of domination. This act is known as Salting The Earth. We see biblical reference to this practice in Judges 9:45: “he killed the people in it, pulled the wall down and sowed the site with salt.”. Salt Coarse salt Salt tectonics
The geologic record in stratigraphy and other natural sciences refers to the entirety of the layers of rock strata — deposits laid down by volcanism or by deposition of sediment derived from weathering detritus including all its fossil content and the information it yields about the history of the Earth: its past climate, geography and the evolution of life on its surface. According to the law of superposition and volcanic rock layers are deposited on top of each other, they harden over time to become a solidified rock column, that may be intruded by igneous rocks and disrupted by tectonic events. At a certain locality on the Earth's surface, the rock column provides a cross section of the natural history in the area during the time covered by the age of the rocks; this is sometimes called the rock history and gives a window into the natural history of the location that spans many geological time units such as ages, epochs, or in some cases multiple major geologic periods—for the particular geographic region or regions.
The geologic record is in no one place complete for where geologic forces one age provide a low-lying region accumulating deposits much like a layer cake, in the next may have uplifted the region, the same area is instead one, weathering and being torn down by chemistry, wind and water. This is to say that in a given location, the geologic record can be and is quite interrupted as the ancient local environment was converted by geological forces into new landforms and features. Sediment core data at the mouths of large riverine drainage basins, some of which go 7 miles deep support the law of superposition; however using broadly occurring deposited layers trapped within differently located rock columns, geologists have pieced together a system of units covering most of the geologic time scale using the law of superposition, for where tectonic forces have uplifted one ridge newly subject to erosion and weathering in folding and faulting the strata, they have created a nearby trough or structural basin region that lies at a relative lower elevation that can accumulate additional deposits.
By comparing overall formations, geologic structures and local strata, calibrated by those layers which are widespread, a nearly complete geologic record has been constructed since the 17th century. Correcting for discordancies can be done in a number of ways and utilizing a number of technologies or field research results from studies in other disciplines. In this example, the study of layered rocks and the fossils they contain is called biostratigraphy and utilizes amassed geobiology and paleobiological knowledge. Fossils can be used to recognize rock layers of the same or different geologic ages, thereby coordinating locally occurring geologic stages to the overall geologic timeline; the pictures of the fossils of monocellular algae in this USGS figure were taken with a scanning electron microscope and have been magnified 250 times. In the U. S. state of South Carolina three marker species of fossil algae are found in a core of rock whereas in Virginia only two of the three species are found in the Eocene Series of rock layers spanning three stages and the geologic ages from 37.2–55.8 MA.
Comparing the record about the discordance in the record to the full rock column shows the non-occurrence of the missing species and that portion of the local rock record, from the early part of the middle Eocene is missing there. This is one form of discordancy and the means geologists use to compensate for local variations in the rock record. With the two remaining marker species it is possible to correlate rock layers of the same age in both South Carolina and Virginia, thereby "calibrate" the local rock column into its proper place in the overall geologic record; as the picture of the overall rock record emerged, discontinuities and similarities in one place were cross-correlated to those in others, it became useful to subdivide the overall geologic record into a series of component sub-sections representing different sized groups of layers within known geologic time, from the shortest time span stage to the largest thickest strata eonothem and time spans eon. Concurrent work in other natural science fields required a time continuum be defined, earth scientists decided to coordinate the system of rock layers and their identification criteria with that of the geologic time scale.
This gives the pairing between the physical layers of the left column and the time units of the center column in the table at right