1.
Geotextile
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Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain. Typically made from polypropylene or polyester, geotextile fabrics come in three forms, woven, needle punched, or heat bonded. Geotextile composites have been introduced and products such as geogrids and meshes have been developed, Geotextiles were originally intended to be an alternative to granular soil filters. The original, and still used, term for geotextiles is filter fabrics. He used different styles of woven monofilament fabrics, all characterized by a high percentage open area. He discussed the need for both adequate permeability and soil retention, along with adequate strength and proper elongation and set the tone for geotextile use in filtration situations. Usually geotextiles are placed at the surface to strengthen the soil. Geotextiles are also used for sand dune armoring to protect upland coastal property from storm surge, wave action, a large sand-filled container within the dune system prevents storm erosion from proceeding beyond the SFC. Using a sloped unit rather than a single tube eliminates damaging scour, erosion control manuals comment on the effectiveness of sloped, stepped shapes in mitigating shoreline erosion damage from storms. Geotextile sand-filled units provide a soft armoring solution for upland property protection, Geotextiles are used as matting to stabilize flow in stream channels and swales. Geotextiles can improve soil strength at a lower cost than conventional soil nailing, in addition, geotextiles allow planting on steep slopes, further securing the slope. Geotextiles have been used to protect the fossil footprints of Laetoli in Tanzania from erosion, rain. In building demolition, geotextile fabrics in combination with wire fencing can contain explosive debris. Coir geotextiles are popular for erosion control, slope stabilization and bioengineering, coir geotextiles last approximately 3 to 5 years depending on the fabric weight. The product degrades into humus, enriching the soil, hard landscape materials Sediment control Koerner, R. M. Designing With Geosynthetics, 6th Edition, Xlibris Publishing Co.914 pgs. Geotextiles, From Design to Applications, Woodhead Publishing Co, john, N. W. M. Geotextiles, Blackie Publishing Ltd
2.
Sylt
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Sylt is an island in northern Germany, part of Nordfriesland district, Schleswig-Holstein, and well known for the distinctive shape of its shoreline. It belongs to the North Frisian Islands and is the largest island in North Frisia, the northernmost island of Germany, it is known for its tourist resorts, notably Westerland, Kampen and Wenningstedt-Braderup, as well as for its 40-kilometre-long sandy beach. It is frequently covered by the media in connection with its situation in the North Sea. Since 1927, Sylt has been connected to the mainland by the Hindenburgdamm causeway, in latter years, it has been a resort for the German jet set and tourists in search of occasional celebrity sighting. With 99.14 square kilometres, Sylt is the fourth-largest German island, Sylt is located from 9 to 16 kilometres off the mainland, to which it is connected by the Hindenburgdamm. Southeast of Sylt are the islands of Föhr and Amrum, to the lies the Danish island of Rømø. The island of Sylt extends for 38 kilometres in a north-south direction, at its northern point at Königshafen, it is only 320 metres wide. Its greatest width, from the town of Westerland in the west to the eastern Nössespitze near Morsum, on the western and northwestern shore, there is a 40-kilometre-long sandy beach. To the east of Sylt, is the Wadden Sea, which belongs to the Schleswig-Holstein Wadden Sea National Park, the islands shape has constantly shifted over time, a process which is still ongoing today. The geestland facing the Wadden Sea gradually turns into fertile marshland around Sylt-Ost, today sources show that Sylt has only been an island since the Grote Mandrenke flood of 1362. The so-called Uwe-Düne is the islands highest elevation with 52.5 metres above sea level, the island in its current form has only existed for about 400 years. Like the mainland geestland, it was formed of moraines from the ice ages, thus being made up of a till core. This sandy core began to erode as it was exposed to a current along the islands steep basement when the sea level rose 8000 years ago. During the process, sediments were accumulated north and south of the island, the west coast, which was originally situated 10 kilometres off todays shore, was thus gradually moved eastward, while at the same time the island began to extend to the north and south. After the ice ages, marshland began to form around this geestland core. In 1141, Sylt is recorded as an island, yet before the Grote Mandrenke flood it belonged to a cut by tidal creeks and, at least during low tide. It is only since this flood that the creation of a spit from sediments began to form the current characteristic shape of Sylt and it is the northern and southern edges of Sylt which were, and still are, the subject of greatest change. For example, Listland was separated from the rest of the island in the 14th century, in addition to the constant loss of land, the inhabitants during the Little Ice Age were constrained by sand drift
3.
Narrow Neck, Queensland
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Narrow Neck is the name of an isthmus that separates the anabranch of the Nerang River from the southern end of Main Beach and the northern end of Surfers Paradise beach. The highway connecting Sydney to Brisbane was constructed at Narrow Neck in 1920, much of the timber removed was still in good condition. In 1971 the Dutch University Delft completed a report for the Queensland State Government recommending the construction of a groyne at Narrow Neck, the Gold Coast City Council examined the idea of a groyne and instead constructed an artificial reef to stabilise the foreshore at Narrow Neck. So far the reef has worked well as a control point. A surprising benefit of the Narrow Neck Reef has been its ability to attract marine growth, Narrow Neck is particularly popular for kite surfing and longboarding. The 350 ×600 m V-shaped artificial reef is located 200 m offshore and deflects the waves to the left and it was built from more than 400 mega sand containers placed between 1 and 10 m below the mean sea level. Each container was about 20 m long and 3. 0–4.8 m in diameter, it was filled with up to 250 m3 of sand and its walls were made of needle-punched nonwoven geotextile, which offered much higher damage resistance compared to conventional materials. The containers were filled on the shore and installed at a rate of up to 10 per day with a GPS-positioned ship, Gold Coast Broadwater Southport Cable Hut
4.
Polymer
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A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Because of their range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure, Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. The units composing polymers derive, actually or conceptually, from molecules of low molecular mass. The term was coined in 1833 by Jöns Jacob Berzelius, though with a distinct from the modern IUPAC definition. The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger, Polymers are studied in the fields of biophysics and macromolecular science, and polymer science. Polyisoprene of latex rubber is an example of a polymer. In biological contexts, essentially all biological macromolecules—i. e, proteins, nucleic acids, and polysaccharides—are purely polymeric, or are composed in large part of polymeric components—e. g. Isoprenylated/lipid-modified glycoproteins, where small molecules and oligosaccharide modifications occur on the polyamide backbone of the protein. The simplest theoretical models for polymers are ideal chains, Polymers are of two types, Natural polymeric materials such as shellac, amber, wool, silk and natural rubber have been used for centuries. A variety of natural polymers exist, such as cellulose. Most commonly, the continuously linked backbone of a used for the preparation of plastics consists mainly of carbon atoms. A simple example is polyethylene, whose repeating unit is based on ethylene monomer, however, other structures do exist, for example, elements such as silicon form familiar materials such as silicones, examples being Silly Putty and waterproof plumbing sealant. Oxygen is also present in polymer backbones, such as those of polyethylene glycol, polysaccharides. Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain or network, during the polymerization process, some chemical groups may be lost from each monomer. This is the case, for example, in the polymerization of PET polyester, the distinct piece of each monomer that is incorporated into the polymer is known as a repeat unit or monomer residue. Laboratory synthetic methods are divided into two categories, step-growth polymerization and chain-growth polymerization. However, some methods such as plasma polymerization do not fit neatly into either category
5.
Civil engineering
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Civil engineering is traditionally broken into a number of sub-disciplines. It is the second-oldest engineering discipline after military engineering, and it is defined to distinguish non-military engineering from military engineering, Civil engineering takes place in the public sector from municipal through to national governments, and in the private sector from individual homeowners through to international companies. Engineering has been an aspect of life since the beginnings of human existence, during this time, transportation became increasingly important leading to the development of the wheel and sailing. The construction of pyramids in Egypt were some of the first instances of large structure constructions, the Romans developed civil structures throughout their empire, including especially aqueducts, insulae, harbors, bridges, dams and roads. In the 18th century, the civil engineering was coined to incorporate all things civilian as opposed to military engineering. The first self-proclaimed civil engineer was John Smeaton, who constructed the Eddystone Lighthouse, in 1771 Smeaton and some of his colleagues formed the Smeatonian Society of Civil Engineers, a group of leaders of the profession who met informally over dinner. Though there was evidence of some meetings, it was little more than a social society. In 1818 the Institution of Civil Engineers was founded in London, the institution received a Royal Charter in 1828, formally recognising civil engineering as a profession. The first private college to teach engineering in the United States was Norwich University. The first degree in engineering in the United States was awarded by Rensselaer Polytechnic Institute in 1835. The first such degree to be awarded to a woman was granted by Cornell University to Nora Stanton Blatch in 1905, throughout ancient and medieval history most architectural design and construction was carried out by artisans, such as stonemasons and carpenters, rising to the role of master builder. Knowledge was retained in guilds and seldom supplanted by advances, structures, roads and infrastructure that existed were repetitive, and increases in scale were incremental. Brahmagupta, an Indian mathematician, used arithmetic in the 7th century AD, based on Hindu-Arabic numerals, Civil engineers typically possess an academic degree in civil engineering. The length of study is three to five years, and the degree is designated as a bachelor of engineering. The curriculum generally includes classes in physics, mathematics, project management, design, after taking basic courses in most sub-disciplines of civil engineering, they move onto specialize in one or more sub-disciplines at advanced levels. In most countries, a degree in engineering represents the first step towards professional certification. After completing a degree program, the engineer must satisfy a range of requirements before being certified. Once certified, the engineer is designated as a engineer, a chartered engineer
6.
Geogrid
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A geogrid is geosynthetic material used to reinforce soils and similar materials. Geogrids are commonly used to reinforce retaining walls, as well as subbases or subsoils below roads or structures, compared to soil, geogrids are strong in tension. This fact allows them to transfer forces to an area of soil than would otherwise be the case. Geogrids are commonly made of materials, such as polyester, polyvinyl alcohol. They may be woven or knitted from yarns, heat-welded from strips of material, or produced by punching a regular pattern of holes in sheets of material, used as such, the major function of the resulting geogrids is in the area of reinforcement. This area, as many other geosynthetics, is very active, with a number of different products, materials, configurations. The ribs of some geogrids are often quite stiff compared to the fibers of geotextiles, as discussed later, not only is rib strength important, but junction strength is also important. The junctions are, of course, where the longitudinal and transverse ribs meet and are connected, currently there are three categories of geogrids. The first, and original, geogrids were invented by Dr Frank Brian Mercer in the United Kingdom at Netlon, a conference in 1984 was helpful in bringing geogrids to the engineering design community. A similar type of drawn geogrid which originated in Italy by Tenax is also available, the second category of geogrids are more flexible, textile-like geogrids using bundles of polyethylene-coated polyester fibres as the reinforcing component. They were first developed by ICI Linear Composites LTD in the United Kingdom around 1980 and this led to the development of polyester yarn geogrids made on textile weaving machinery. In this process hundreds of continuous fibers are gathered together to form yarns which are woven into longitudinal, the cross-overs are joined by knitting or intertwining before the entire unit is protected by a subsequent coating. Bitumen, latex, or PVC are the usual coating materials, geosynthetics within this group are manufactured by many companies having various trademarked products. There are possibly as many as 25 companies manufacturing coated yarn-type polyester geogrids on a worldwide basis, the third category of geogrids are made by laser or ultrasonically bonding together polyester or polypropylene rods or straps in a gridlike pattern. Two manufacturers currently make such geogrids, the geogrid sector is extremely active not only in manufacturing new products, but also in providing significant technical information to aid the design engineer
7.
Geonets
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A geonet is a geosynthetic material consisting of integrally connected parallel sets of ribs overlying similar sets at various angles for in-plane drainage of liquids or gases. Geonets are often laminated with geotextiles on one or both surfaces and are referred to as drainage geocomposites. They are competitive with other drainage geocomposites having different core configurations, Geonets are formed by a continuous extrusion process into a netlike configuration of parallel sets of homogeneously interconnected ribs. There are three categories of geonets, the following are illustrated, Biplanar geonets, These are the original and most common types and consist of two sets of intersecting ribs at different angles and spacings. The ribs themselves are of different sizes and shapes for different styles, triplanar geonets, These have parallel central ribs with smaller sets of ribs above and beneath mainly for geometric stability. Other geonets, These newer geonet structures have either box shaped channels or protruding columns from a support network. Each of the categories have variations within themselves and new product development by various manufacturers is quite active. All geonets that are available are made from polyethylene resin. The density varies from 0.94 to 0.96 mg/l, in this regard, the resin is true high-density polyethylene unlike the density used in HDPE geomembranes that is really medium density. The resin is formulated with 2.0 to 2. 5% carbon black, while quite different in the manufacture or configuration than geonets are competitive geosynthetic products called geospacers. Their drainage cores consists of nubs, columns, cuspations, or 3-D networks of stiff polymer strands and they are generally used for drainage behind retaining walls, plaza decks or green roofs. Since the primary function of a geonet is to convey liquid within the plane of its structure, however, other features, which may influence this value over the service lifetime of the geonet, are also of importance. Thus, a number of physical, mechanical, endurance, the tests for physical properties are either covered in ASTM, ISO or GRI Standards. As seen in the equation, q/W and θ carry the same units and are related to one another by means of the hydraulic gradient i. At a hydraulic gradient of 1.0, they are numerically identical, at all other values of hydraulic gradient they are not equal. Also note that the system should be saturated and flow must be laminar in order to use transmissivity, when in doubt, it is usually best to use flow rate per unit width. Geonets are supplied in rolls from 2.0 to 6.7 m wide and they should be placed and covered in a timely manner. Contamination can occur from soil, miscellaneous sediment, construction debris, ingrowing vegetation, the rolls are usually placed with their roll directions oriented up-and-down slope, rather than along them
8.
Geomembrane
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Continuous polymer sheet geomembranes are, by far, the most common. These raw materials are processed into sheets of various widths and thickness by extrusion, calendering. Geomembranes dominate the sales of products, at 1.8 billion USD per year worldwide. Projections for future geomembrane usage are strongly dependent on the application, landfill liners and covers in North America and Europe will probably see modest growth, while in other parts of the world growth could be dramatic. Perhaps the greatest increases will be seen in the containment of coal ash, the majority of generic geomembrane test methods that are referenced worldwide are by the ASTM International|American Society of Testing and Materials due to their long history in this activity. More recent are test method developed by the International Organization for Standardization, lastly, the Geosynthetic Research Institute has developed test methods that are only for test methods not addressed by ASTM or ISO. Of course, individual countries and manufacturers often have specific proprietary test methods, the main physical properties of geomembranes in the as-manufactured state are, Thickness Density Melt flow index Mass per unit area Vapor transmission. There are a number of tests that have been developed to determine the strength of polymeric sheet materials. Many have been adopted for use in evaluating geomembranes and they represent both quality control and design, i. e. index versus performance tests. Tensile strength and elongation tear resistance impact resistance puncture resistance interface shear strength anchorage strength stress cracking, any phenomenon that causes polymeric chain scission, bond breaking, additive depletion, or extraction within the geomembrane must be considered as compromising to its long-term performance. There are a number of concerns in this regard. While each is material-specific, the general trend is to cause the geomembrane to become brittle in its stress-strain behavior over time. Obviously, many of the physical and mechanical properties could be used to monitor the degradation process. Ultraviolet light exposure radioactive degradation biological degradation chemical degradation thermal behavior oxidative degradation, geomembranes degrade slowly enough that their lifetime behavior is as yet uncharted. Thus, accelerated testing, either by stress, elevated temperatures and/or aggressive liquids, is the only way to determine how the material will behave long-term. Rate process method, Used in Europe for pipes and geomembranes, hoechst multiparameter approach, A method that utilizes biaxial stresses and stress relaxation for lifetime prediction and can include seams as well. Arrhenius modeling, A method for testing geomembranes described in Koerner for both buried and exposed conditions and this reorganization results from an input of energy that originates from either thermal or chemical processes. These processes may involve the addition of polymer in the area to be bonded
9.
Geosynthetic clay liners
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The lower the hydraulic conductivity the more effective the GCL will be at retaining seepage inside of the landfill. Bentonite composed predominantly of montmorillonite or other expansive clays, are preferred, a general GCL construction would consist of two layers of geosynthetics stitched together enclosing a layer of natural or processed sodium bentonite. GCLs are produced by large companies in North America, Europe. The United States Environmental Protection Agency currently regulates landfill construction and design in the US through several legislations, the use of GCLs as a separate category of geosynthetics appears to have been in the United States in 1988 in solid waste containment as a backup to a geomembrane. The product was Claymax which is mixed with an adhesive so as to bond the clay between two geotextiles, one below and the other above the bentonite in the center. About the same time a different product in Germany, Bentofix, was manufactured by placing bentonite powder between two geotextiles and then punching the three-components system together. The engineering function of a GCL is containment as a barrier to water, leachate or other liquids. As such, they are used as replacements for either compacted clay liners or geomembranes, the ultimate in liner security is probably a three component composite geomembrane/geosynthetic clay liner/compacted clay liner which has seen use as a landfill liner on many occasions
10.
Geofoam
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Geofoam is expanded polystyrene or extruded polystyrene manufactured into large lightweight blocks. The blocks vary in size but are often 2 m ×0.75 m ×0.75 m, the primary function of geofoam is to provide a lightweight void fill below a highway, bridge approach, embankment or parking lot. EPS Geofoam minimizes settlement on underground utilities, Geofoam is also used in much broader applications, including lightweight fill, green roof fill, compressible inclusions, thermal insulation, and drainage. The cross-sectional geometry of a tube typically has a simple geometric shape and is on the order of 25 mm across. The overall cross-section of the assemblage of bundled tubes resembles a honeycomb that gives it its name, presently, only rigid polymers have been used as geocomb material. The first use of EPS Geofoam was in Oslo, Norway in 1972, Geofoam was used in the embankments around the Flom Bridge in an effort to reduce settlements. Prior to installing geofoam, this area experienced 20–30 centimeters of settlement annually causing extreme roadway damage, since then, two more conferences were held in Tokyo, Japan and Salt Lake City, US, in 1996 and 2001, respectively. The most recent conference was held in June 2011 in Lillestrom, between 1985 and 1987, Japan used over 1,300,000 m3 of geofoam in 2,000 projects. Testing and use of geofoam in these projects demonstrated the advantages of geofoam as a lightweight fill. For example, Geofoam was placed beneath runways in Japanese airports, proving the material can sustain heavy, Geofoam was first used in the United States in 1989 on Highway 160 between Durango and Mancos, Colorado. An increase in rainfall caused a landslide, destroying part of the highway, Geofoam was used to create highway side slope stabilization to prevent any similar issues. The use of geofoam versus conventional restoration resulted in an 84% reduction to the total cost of the project, the largest geofoam project in the United States took place from 1997 to 2001 on Interstate 15 in Salt Lake City, Utah. Geofoam was chosen to minimize that amount of utilities that would need to be relocated or remodeled for the project, a total of 3,530,000 cu ft of geofoam was used, and approximately $450,000 was saved by eliminating the need to relocate utility poles. Geofoam was also used in embankments and bridge abutments for base stability, subsequently, because of the success of usage of geofoam for the I-15 Reconstruction Project, the Utah Transit Authority has used geofoam embankment for its light rail and commuter rail lines. Geofoam is up to 50 times lighter than other traditional fills with similar compressive strengths and this allows geofoam to maximize the available right-of-way on an embankment. Geofoams light weight and ease of installation reduces construction time and labor costs, embankments using geofoam allow for a great reduction in necessary side slopes compared to typical fills. Reducing the side slope of the embankment can increase the space on either side. These embankments can also be built upon soils affected by differential settlement without being affected, maintenance costs associated with geofoam embankments are significantly lower when compared to embankments using natural soil
11.
Cellular confinement
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Research and development of cellular confinement systems began with the U. S. Army Corps of Engineers in 1975 to devise a method for building tactical roads over soft ground. Today cellular confinement systems are made from strips 50–200 mm wide. The CCS is folded and shipped to the job site in a collapsed configuration, efforts for civilian commercialization of the cellular confinement system by the Presto Products Company, led to the Geoweb®. This cellular confinement system was made from high density polyethylene, relatively strong, lightweight, the cellular confinement system was used for load support, slope erosion control and channel lining and earth retention applications in the United States and Canada in the early 1980s. However, Richardson laments 25 years later on the absence of research papers on geocells in all of the geosynthetic national and international conferences. Fortunately in the last decade research and development in geocell systems expanded significantly, additional literature reviews can be found in Kief et al. Geocells are recognized as a suitable geosynthetic reinforcement of granular soils to support static and moving wheel loads on roadways, railways, but stiffness of the geocells was identified as a key influencing factor for geocell reinforcement, and hence the rigidity of the entire pavement structure. Utilizing recent advances in polymer and nano technology, extensive R&D was carried out to improve geocell wall stiffness, thermal and elastic properties, the result was a cellular confinement system manufactured from Neoloy, a novel polymeric alloy. NPA is an alloy of polyamide nano-fibers dispersed in a polyethylene matrix. that are subject to long-term heavy static and dynamic loading. Laboratory plate loading tests, full-scale moving wheel tests, and field demonstrations showed that the performance of geocell-reinforced bases depends on the modulus of the geocell. Geocells with an elastic modulus had a higher bearing capacity. NPA Geocells showed higher results in ultimate bearing capacity, stiffness, CCS have been successfully installed in thousands of projects worldwide. The lifespan of CCS in slope protection applications, for example, is critical as vegetative growth. This in effect compensates for any loss of confinement in the CCS. Similarly, load support applications for low volume roads that are not subject to heavy loading usually have a design life. However, in applications such as reinforcement of the structural layer of asphalt highway pavements. The required design life for such roads under heavy loads is typically 20–25 years. The few standards for CCS were developed more than 40 years ago and have changed little since, on the other hand ISO/ASTM procedures have been developed for testing polymers in the space and automobile industries, as well as for other geosynthetic products
12.
Geocomposite
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Thus, the benefit/cost ratio is maximized. Such geocomposites will generally be geosynthetic materials, but not always, in some cases it may be more advantageous to use a nonsynthetic material with a geosynthetic one for optimum performance and/or least cost. As seen in the following, the number of possibilities is huge — the only limits being ones ingenuity, there are five basic functions that can be provided, separation, reinforcement, filtration, drainage, and containment. Such geocomposites are regularly used in intercepting and conveying leachate in landfill liner and cover systems and these drainage geocomposites also make excellent drains to intercept water in a capillary zone where frost heave or salt migration is a problem. In all cases, the liquid enters through the geotextile and then travels horizontally within the geonet to a suitable exit, geotextiles can be laminated on one or both sides of a geomembrane for a number of purposes. The geotextiles provide increased resistance to puncture, tear propagation, and friction related to sliding, as well as providing tensile strength in, quite often, however, the geotextiles are of the nonwoven, needle-punched variety and are of relatively heavy weight. In such cases the geotextile component acts as a media, since its in-plane transmissivity feature can conduct water. Since some types of geomembranes and geogrids can be made from the material, they can be bonded together to form an impervious membrane barrier with enhanced strength. A needle punched nonwoven geotextile bonded to a geogrid provides in-plane drainage while the geogrid provides tensile reinforcement, such geotextile-geogrid composites are used for internal drainage of low-permeability backfill soils for reinforced walls and slopes. The synergistic properties of each component enhances the behavior of the final product, the core must be protected by a geotextile, acting as a filter and separator, on one or both sides. Various systems are available, each focused on a particular application, the first is known as wick drains in the U. S. and prefabricated vertical drains, PVDs, in Europe. The 100 mm wide by 5 mm thick polymer cores are often fluted for ease of conducting water, a geotextile acting as a filter and separator is socked around the core. The emergence of such wick drains, or PVDs, has all, the second type is in the form of drainage panels, the rigid polymer core being nubbed, columned, dimpled or a three-dimensional net. With a geotextile on one side it makes an excellent drain on the side of retaining walls, basement walls. The cores are sometimes vacuum formed dimples or stiff 3-D meshes, as with wick drains, the geotextile is the filter/separator and the thick polymer core is the drain. Many systems of type are available, the latest addition having a thin pliable geomembrane on the side facing the wall. The third type within this area of drainage geocomposites is the category of prefabricated edge drains, the systems are very rapid in their installation and extremely cost effective
13.
Geotechnical engineering
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Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. A typical geotechnical engineering project begins with a review of project needs to define the material properties. Site investigations are needed to gain an understanding of the area in or on which the engineering will take place, a geotechnical engineer then determines and designs the type of foundations, earthworks, and/or pavement subgrades required for the intended man-made structures to be built. Foundations built for above-ground structures include shallow and deep foundations, retaining structures include earth-filled dams and retaining walls. Earthworks include embankments, tunnels, dikes and levees, channels, reservoirs, deposition of hazardous waste, Geotechnical engineering is also related to coastal and ocean engineering. Coastal engineering can involve the design and construction of wharves, marinas, ocean engineering can involve foundation and anchor systems for offshore structures such as oil platforms. The fields of engineering and engineering geology are closely related. However, the field of engineering is a specialty of engineering. Humans have historically used soil as a material for flood control, irrigation purposes, burial sites, building foundations, as the cities expanded, structures were erected supported by formalized foundations, Ancient Greeks notably constructed pad footings and strip-and-raft foundations. Until the 18th century, however, no basis for soil design had been developed. Several foundation-related engineering problems, such as the Leaning Tower of Pisa, 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, a rudimentary soil classification system was also developed based on a materials unit weight, which is 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 pressures against military ramparts. By combining Coulombs theory with Christian Otto Mohrs 2D stress state, 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 Darcys Law describing the flow of fluids in porous media, albert Atterberg developed the clay consistency indices that are still used today for soil classification. Osborne Reynolds recognized in 1885 that shearing causes volumetric dilation of dense, modern geotechnical engineering is said to have begun in 1925 with the publication of Erdbaumechanik by Karl Terzaghi. Terzaghi also developed the framework for theories of bearing capacity of foundations, in his 1948 book, Donald Taylor recognized that interlocking and dilation of densely packed particles contributed to the peak strength of a soil. Critical state soil mechanics is the basis for many contemporary advanced constitutive models describing the behavior of soil, Geotechnical centrifuge modeling is a method of testing physical scale models of geotechnical problems
14.
Transport
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Transport or transportation is the movement of people, animals and goods from one location to another. Modes of transport include air, rail, road, water, cable, pipeline, the field can be divided into infrastructure, vehicles and operations. Transport is important because it enables trade between people, which is essential for the development of civilizations, terminals may be used both for interchange of passengers and cargo and for maintenance. Vehicles traveling on these networks may include automobiles, bicycles, buses, trains, trucks, people, helicopters, operations deal with the way the vehicles are operated, and the procedures set for this purpose including financing, legalities and policies. In the transport industry, operations and ownership of infrastructure can be public or private, depending on the country. Passenger transport may be public, where operators provide scheduled services, freight transport has become focused on containerization, although bulk transport is used for large volumes of durable items. Transport plays an important part in growth and globalization, but most types cause air pollution. While it is subsidized by governments, good planning of transport is essential to make traffic flow. A mode of transport is a solution that makes use of a type of vehicle, infrastructure. The transport of a person or of cargo may involve one mode or several of the modes, each mode has its own advantages and disadvantages, and will be chosen for a trip on the basis of cost, capability, and route. Human powered transport, a form of transportation, is the transport of people and/or goods using human muscle-power. Modern technology has allowed machines to enhance human power, human-powered vehicles have also been developed for difficult environments, such as snow and water, by watercraft rowing and skiing, even the air can be entered with human-powered aircraft. Animal-powered transport is the use of working animals for the movement of people, humans may ride some of the animals directly, use them as pack animals for carrying goods, or harness them, alone or in teams, to pull sleds or wheeled vehicles. A fixed-wing aircraft, commonly called airplane, is a craft where movement of the air in relation to the wings is used to generate lift. The term is used to distinguish this from rotary-wing aircraft, where the movement of the lift surfaces relative to the air generates lift, a gyroplane is both fixed-wing and rotary-wing. Fixed-wing aircraft range from small trainers and recreational aircraft to large airliners, two things necessary for aircraft are air flow over the wings for lift and an area for landing. The majority of aircraft also need an airport with the infrastructure to receive maintenance, restocking, refueling and for the loading and unloading of crew, cargo and passengers. While the vast majority of land and take off on land, some are capable of take off and landing on ice, snow
15.
Hydraulics
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Hydraulics is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids or fluids. At a very basic level, hydraulics is the version of pneumatics. Fluid mechanics provides the foundation for hydraulics, which focuses on the applied engineering using the properties of fluids. In fluid power, hydraulics are used for the generation, control, hydraulic topics range through some parts of science and most of engineering modules, and cover concepts such as pipe flow, dam design, fluidics and fluid control circuitry, pumps. The principles of hydraulics are in use naturally in the body within the heart. Free surface hydraulics is the branch of hydraulics dealing with surface flow, such as occurring in rivers, canals, lakes, estuaries. Its sub-field open channel flow studies the flow in open channels, the word hydraulics originates from the Greek word ὑδραυλικός which in turn originates from ὕδωρ and αὐλός. Early uses of water power date back to Mesopotamia and ancient Egypt, other early examples of water power include the Qanat system in ancient Persia and the Turpan water system in ancient Central Asia. The Greeks constructed sophisticated water and hydraulic power systems, an example is the construction by Eupalinos, under a public contract, of a watering channel for Samos, the Tunnel of Eupalinos. An early example of the usage of hydraulic wheel, probably the earliest in Europe, is the Perachora wheel, notable is the construction of the first hydraulic automata by Ctesibius and Hero of Alexandria. Hero describes a number of working machines using hydraulic power, such as the force pump, in ancient China there was Sunshu Ao, Ximen Bao, Du Shi, Zhang Heng, and Ma Jun, while medieval China had Su Song and Shen Kuo. Du Shi employed a waterwheel to power the bellows of a blast furnace producing cast iron, Zhang Heng was the first to employ hydraulics to provide motive power in rotating an armillary sphere for astronomical observation. In ancient Sri Lanka, hydraulics were used in the ancient kingdoms of Anuradhapura. The discovery of the principle of the tower, or valve pit. By the first century AD, several irrigation works had been completed. The coral on the rock at the site includes cisterns for collecting water. They were among the first to use of the siphon to carry water across valleys. They used lead widely in plumbing systems for domestic and public supply, hydraulic mining was used in the gold-fields of northern Spain, which was conquered by Augustus in 25 BC
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Land development
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In an economics context, land development is also sometimes advertised as land improvement or land amelioration. It refers to investments making land more usable by humans, for accounting purposes it refers to any variety of projects that increase the value of the property. Most are depreciable, but some improvements are not able to be depreciated because a useful life cannot be determined. Home building and containment are two of the most common and the oldest types of development and this profit enhancement means identifying and developing the best scheme for the local marketplace, whilst satisfying the local planning process. Development Analysis puts development prospects and the development process itself under the microscope, development analysis can add significantly to the value of land and development, and as such is a crucial tool for landowners and developers. It is a step in Kevin A. Lynchs 1960 book The Image of the City. The landowner can share in additional planning gain via an awareness of the development potential. This is done via a residual development appraisal or residual valuation, the residual appraisal calculates the sale value of the end product, and hypothetically deducts costs, including planning and construction costs, finance costs and developers profit. The residue, or leftover proportion, represents the land value, therefore, in maximising the GDV, land value is concurrently enhanced. Land value is highly sensitive to supply and demand, build costs, planning and affordable housing contributions, understanding the intricacies of the development system and the effect of value drivers can result in massive differences in the landowners sale value. Land improvement in the economic sense can often lead to degradation from the ecological perspective. Land development and the change in land value does not usually take into account changes in the ecology of the developed area, new creation of farmland will rely on the conversion and development of previous forests, savannas or grassland. Recreation of farmland from wasteland, deserts or previous impervious surfaces is considerably less frequent because of the degraded or missing fertile soil in the latter, starting from forests, land is made arable by assarting or slash-and-burn. Agricultural development furthermore includes, Hydrological measures Soil improvement, road construction Because the newly created farmland is more prone to erosion than soil stabilized by tree roots, such a conversion may mean irreversible crossing of an ecological threshold. The resulting deforestation is not easily compensated for by reforestation or afforestation. Examples of land restoration/land rehabilitation counted as land development in the strict sense are still rare, however, renaturation, reforestation, stream restoration may all contribute to a healthier environment and quality of life, especially in densely populated regions. The same is true for planned vegetation like parks and gardens, but restoration plays a particular role, because it reverses previous conversions to built and agricultural areas
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Road
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Roads consist of one or two roadways, each with one or more lanes and any associated sidewalks and road verges. Roads that are available for use by the public may be referred to as parkways, avenues, freeways, interstates, highways, or primary, secondary, and tertiary local roads. In urban areas roads may diverge through a city or village and be named as streets, serving a function as urban space easement. Modern roads are normally smoothed, paved, or otherwise prepared to allow easy travel, historically many roads were simply recognizable routes without any formal construction or maintenance. In the United Kingdom there is ambiguity between the terms highway and road. The Highway code details rules for road users and this includes footpaths, bridleways and cycle tracks, and also road and driveways on private land and many car parks. Vehicle Excise Duty, a use tax, is payable on some vehicles used on the public road. The definition of a road depends on the definition of a highway, in the United States, laws distinguish between public roads, which are open to public use, and private roads, which are privately controlled. The assertion that the first pathways were the trails made by animals has not been universally accepted, others believe that some roads originated from following animal trails. The Icknield Way is given as an example of type of road origination. By about 10,000 BC, rough roads/pathways were used by human travelers, the worlds oldest known paved road was constructed in Egypt some time between 2600 and 2200 BC. Stone-paved streets are found in the city of Ur in the Middle East dating back to 4000 BC, corduroy roads are found dating to 4000 BC in Glastonbury, England. The Sweet Track, a timber causeway in England, is one of the oldest engineered roads discovered. Built in winter 3807 BC or spring 3806 BC, tree-ring dating enabled very precise dating and it was claimed to be the oldest road in the world until the 2009 discovery of a 6, 000-year-old trackway in Plumstead, London. Brick-paved streets were used in India as early as 3000 BC, in 500 BC, Darius I the Great started an extensive road system for Persia, including the Royal Road, which was one of the finest highways of its time. The road remained in use after Roman times, a hybrid of road transport and ship transport beginning in about 1740 is the horse-drawn boat in which the horse follows a cleared path along the river bank. From about 312 BC, the Roman Empire built straight strong stone Roman roads throughout Europe and North Africa, at its peak the Roman Empire was connected by 29 major roads moving out from Rome and covering 78,000 kilometers or 52,964 Roman miles of paved roads. In the 8th century AD, many roads were built throughout the Arab Empire, the most sophisticated roads were those in Baghdad, which were paved with tar
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Aerodrome
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An aerodrome or airdrome is a location from which aircraft flight operations take place, regardless of whether they involve air cargo, passengers, or neither. Aerodromes include small general aviation airfields, large airports. The term airport may imply a certain stature that an aerodrome may not have achieved and that is to say, all airports are aerodromes, but not all aerodromes are airports. Usage of the term aerodrome remains more common in the UK and Commonwealth nations, a water aerodrome is an area of open water used regularly by seaplanes or amphibious aircraft for landing and taking off. The word aerodrome derives from Ancient Greek ἀήρ, air, and δρόμος, road or course, an ancient linguistic parallel is hippodrome, derived from ἵππος, horse, and δρόμος, course. In Canada and Australia, aerodrome is a term of art for any area of land or water used for aircraft operation. International Civil Aviation Organization documents use the aerodrome, for example, in the Annex to the ICAO Convention about aerodromes, their physical characteristics. However, the airfield or airport mostly superseded use of aerodrome after World War II. The city of the first aerodrome in the world is a French commune named Viry-Chatillon, the unimproved airfield remains a phenomenon in military aspects. The DHC-4 Caribou served in the U. S. military in Vietnam, landing on rough, earlier, the Ju-52 and Fieseler Storch could do the same, one example of the latter taking off from the Führerbunker whilst completely surrounded by Russian troops. An airport is an aerodrome certificated for commercial flights, an air base is an aerodrome with significant facilities to support aircraft and crew. The term is reserved for military bases, but also applies to civil seaplane bases. An airstrip is an aerodrome that consists only of a runway with perhaps fueling equipment. They are generally in remote locations, many airstrips were built on the hundreds of islands in the Pacific Ocean during World War II. A few airstrips grew to become full-fledged airbases as strategic or economic importance of a region increased over time. An Advanced Landing Ground was an airstrip used by the Allies in the run-up to and during the invasion of Normandy. A water aerodrome is an area of water used regularly by seaplanes or amphibious aircraft for landing and taking off. It may have a building on land and/or a place where the plane can come to shore
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Rail transport
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Rail transport is a means of conveyance of passengers and goods on wheeled vehicles running on rails, also known as tracks. It is also referred to as train transport. In contrast to road transport, where vehicles run on a flat surface. Tracks usually consist of rails, installed on ties and ballast, on which the rolling stock, usually fitted with metal wheels. Other variations are possible, such as slab track, where the rails are fastened to a concrete foundation resting on a prepared subsurface. Rolling stock in a transport system generally encounters lower frictional resistance than road vehicles, so passenger. The operation is carried out by a company, providing transport between train stations or freight customer facilities. Power is provided by locomotives which either draw electric power from a railway system or produce their own power. Most tracks are accompanied by a signalling system, Railways are a safe land transport system when compared to other forms of transport. The oldest, man-hauled railways date back to the 6th century BC, with Periander, one of the Seven Sages of Greece, Rail transport blossomed after the British development of the steam locomotive as a viable source of power in the 19th centuries. With steam engines, one could construct mainline railways, which were a key component of the Industrial Revolution, also, railways reduced the costs of shipping, and allowed for fewer lost goods, compared with water transport, which faced occasional sinking of ships. The change from canals to railways allowed for markets in which prices varied very little from city to city. In the 1880s, electrified trains were introduced, and also the first tramways, starting during the 1940s, the non-electrified railways in most countries had their steam locomotives replaced by diesel-electric locomotives, with the process being almost complete by 2000. During the 1960s, electrified high-speed railway systems were introduced in Japan, other forms of guided ground transport outside the traditional railway definitions, such as monorail or maglev, have been tried but have seen limited use. The history of the growth, decline and restoration to use of transport can be divided up into several discrete periods defined by the principal means of motive power used. The earliest evidence of a railway was a 6-kilometre Diolkos wagonway, trucks pushed by slaves ran in grooves in limestone, which provided the track element. The Diolkos operated for over 600 years, Railways began reappearing in Europe after the Dark Ages. The earliest known record of a railway in Europe from this period is a window in the Minster of Freiburg im Breisgau in Germany
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Retaining wall
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Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to. A retaining wall is a designed and constructed to resist the lateral pressure of soil. A basement wall is one kind of retaining wall. But the term refers to a cantilever retaining wall, which is a freestanding structure without lateral support at its top. These are cantilevered from a footing and rise above the grade on one side to retain a level grade on the opposite side. The walls must resist the pressures generated by loose soils or, in some cases. Every retaining wall supports a “wedge” of soil, the wedge is defined as the soil which extends beyond the failure plane of the soil type present at the wall site, and can be calculated once the soil friction angle is known. As the setback of the wall increases, the size of the wedge is reduced. This reduction lowers the pressure on the retaining wall, the most important consideration in proper design and installation of retaining walls is to recognize and counteract the tendency of the retained material to move downslope due to gravity. Lateral earth pressures are zero at the top of the wall, earth pressures will push the wall forward or overturn it if not properly addressed. Also, any groundwater behind the wall that is not dissipated by a system causes hydrostatic pressure on the wall. The total pressure or thrust may be assumed to act at one-third from the lowest depth for lengthwise stretches of uniform height. Unless the wall is designed to retain water, It is important to have proper drainage behind the wall in order to limit the pressure to the design value. Drainage materials will reduce or eliminate the pressure and improve the stability of the material behind the wall. Drystone retaining walls are normally self-draining.5 against lateral sliding and overturning, gravity walls depend on their mass to resist pressure from behind and may have a batter setback to improve stability by leaning back toward the retained soil. For short landscaping walls, they are made from mortarless stone or segmental concrete units. Dry-stacked gravity walls are somewhat flexible and do not require a rigid footing, earlier in the 20th century, taller retaining walls were often gravity walls made from large masses of concrete or stone. Cantilevered retaining walls are made from a stem of steel-reinforced
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Reservoir
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A reservoir is a storage space for fluids. These fluids may be water, hydrocarbons or gas, a reservoir usually means an enlarged natural or artificial lake, storage pond or impoundment created using a dam or lock to store water. Reservoirs can be created by controlling a stream that drains a body of water. They can also be constructed in river valleys using a dam, alternately, a reservoir can be built by excavating flat ground or constructing retaining walls and levees. Tank reservoirs store liquids or gases in storage tanks that may be elevated, at grade level, tank reservoirs for water are also called cisterns. Underground reservoirs are used to store liquids, principally either water or petroleum, a dam constructed in a valley relies on the natural topography to provide most of the basin of the reservoir. Dams are typically located at a part of a valley downstream of a natural basin. The valley sides act as walls, with the dam located at the narrowest practical point to provide strength. In many reservoir construction projects, people have to be moved and re-housed, construction of a reservoir in a valley will usually need the river to be diverted during part of the build, often through a temporary tunnel or by-pass channel. In hilly regions, reservoirs are constructed by enlarging existing lakes. Sometimes in such reservoirs the new top water level exceeds the height on one or more of the feeder streams such as at Llyn Clywedog in Mid Wales. In such cases additional side dams are required to contain the reservoir, where water is pumped or siphoned from a river of variable quality or quantity, bank-side reservoirs may be built to store the water. Such reservoirs are usually formed partly by excavation and partly by building a complete encircling bund or embankment, the water stored in such reservoirs may stay there for several months, during which time normal biological processes may substantially reduce many contaminants and almost eliminate any turbidity. The use of reservoirs also allows water abstraction to be stopped for some time. Service reservoirs store fully treated potable water close to the point of distribution, many service reservoirs are constructed as water towers, often as elevated structures on concrete pillars where the landscape is relatively flat. Other service reservoirs can be almost entirely underground, especially in hilly or mountainous country. In the United Kingdom, Thames Water has many underground reservoirs, sometimes called cisterns, built in the 1800s. A good example is the Honor Oak Reservoir in London, constructed between 1901 and 1909, when it was completed it was said to be the largest brick built underground reservoir in the world and it is still one of the largest in Europe
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Canal
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Canals and navigations are human-made channels for water conveyance, or to service water transport vehicles. In the vernacular, both are referred to as canals, and in most cases, the works will have a series of dams. These areas are referred to as water levels, often just called levels. In contrast, a canal cuts across a drainage divide atop a ridge, many canals have been built at elevations towering over valleys and others water ways crossing far below. Cities need a lot of water and many canals with sources of water at a higher level can deliver water to a destination where there is a lack of water. The Roman Empires Aqueducts were such water supply canals, a navigation is a series of channels that run roughly parallel to the valley and stream bed of an unimproved river. A navigation always shares the drainage basin of the river, a vessel uses the calm parts of the river itself as well as improvements, traversing the same changes in height. A true canal is a channel that cuts across a drainage divide, most commercially important canals of the first half of the 19th century were a little of each, using rivers in long stretches, and divide crossing canals in others. This is true for many canals still in use, there are two broad types of canal, Waterways, canals and navigations used for carrying vessels transporting goods and people. These can be subdivided into two kinds, Those connecting existing lakes, rivers, other canals or seas and oceans and those connected in a city network, such as the Canal Grande and others of Venice Italy, the gracht of Amsterdam, and the waterways of Bangkok. Aqueducts, water canals that are used for the conveyance and delivery of potable water for human consumption, municipal uses, hydro power canals. Historically canals were of importance to commerce and the development, growth. In 1855 the Lehigh Canal carried over 1.2 million tons of burning anthracite coal, by the 1930s the company which built. By the early 1880s, canals which had little ability to compete with rail transport, were off the map. In the next couple of decades, coal was diminished as the heating fuel of choice by oil. Later, after World War I when motor-trucks came into their own, Canals are built in one of three ways, or a combination of the three, depending on available water and available path, Human made streams A canal can be created where no stream presently exists. Either the body of the canal is dug or the sides of the canal are created by making dykes or levees by piling dirt, stone, the water for the canal must be provided from an external source, like streams or reservoirs. Where the new waterway must change elevation engineering works like locks, lifts or elevators are constructed to raise, examples include canals that connect valleys over a higher body of land, like Canal du Midi, Canal de Briare and the Panama Canal
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Dam
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A dam is a barrier that impounds water or underground streams. Reservoirs created by not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture. Hydropower is often used in conjunction with dams to generate electricity, a dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. The word dam can be traced back to Middle English, and before that, from Middle Dutch, the first known appearance of dam occurs in 1165. However, there is one village, Obdam, that is mentioned in 1120. The word seems to be related to the Greek word taphos, so the word should be understood as dike from dug out earth. The names of more than 40 places from the Middle Dutch era such as Amsterdam and Rotterdam, early dam building took place in Mesopotamia and the Middle East. Dams were used to control the level, for Mesopotamias weather affected the Tigris. The earliest known dam is the Jawa Dam in Jordan,100 kilometres northeast of the capital Amman and this gravity dam featured an originally 9-metre-high and 1 m-wide stone wall, supported by a 50 m-wide earth rampart. The structure is dated to 3000 BC, the Ancient Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, located about 25 km south of Cairo, was 102 m long at its base and 87 m wide. The structure was built around 2800 or 2600 BC as a dam for flood control. During the Twelfth Dynasty in the 19th century BC, the Pharaohs Senosert III, Amenemhat III, two dams called Ha-Uar running east-west were built to retain water during the annual flood and then release it to surrounding lands. The lake called Mer-wer or Lake Moeris covered 1,700 km2 and is today as Berkat Qaroun. One of the wonders of the ancient world was the Great Dam of Marib in Yemen. Repairs were carried out during various periods, most important around 750 BC and these extensive works were not actually finalized until 325 AD and allowed the irrigation of 25,000 acres. By the mid-late 3rd century BC, an intricate water-management system within Dholavira in modern-day India was built, the system included 16 reservoirs, dams and various channels for collecting water and storing it. Eflatun Pınar is a Hittite dam and spring temple near Konya and it is thought to be from the time of the Hittite empire between the 15th and 13th century BC
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Erosion control
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Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development, coastal areas, river banks and construction. Effective erosion controls handle surface runoff and are important techniques in preventing water pollution, soil loss, wildlife habitat loss, erosion controls are used in natural areas, agricultural settings or urban environments. In urban areas erosion controls are part of stormwater runoff management programs required by local governments. The controls often involve the creation of a barrier, such as vegetation or rock. They also involve building and maintaining storm drains, on construction sites they are often implemented in conjunction with sediment controls such as sediment basins and silt fences. Bank erosion is a process, without it, rivers would not meander. However, land management patterns that change the hydrograph and/or vegetation cover can act to increase or decrease channel migration rates, in many places, whether or not the banks are unstable due to human activities, people try to keep a river in a single place. This can be done for environmental reclamation or to prevent a river from changing course into land that is being used by people, one way that this is done is by placing riprap or gabions along the bank. These models have addressed both gully and sheet erosion, earliest models were a simple set of linked equations which could be employed by manual calculation. By the 1970s the models had expanded to complex computer models addressing nonpoint source pollution with thousands of lines of computer code, the more complex models were able to address nuances in micrometerology, soil particle size distributions and micro-terrain variation
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Sediment control
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A sediment control is a practice or device designed to keep eroded soil on a construction site, so that it does not wash off and cause water pollution to a nearby stream, river, lake, or sea. Sediment controls are usually employed together with erosion controls, which are designed to prevent or minimize erosion, sediment controls are generally designed to be temporary measures, however, some can be used for storm water management purposes. It is designed to reduce turbidity in water bodies and involves collection of sediment-laden stormwater in a basin or tank. An example video of chemical dosing on slow settling solids is on YouTube and this causes the sediment to settle so it can be more easily removed from the water. Some of the flocculent chemicals used for sediment treatment are chitosan, the water is then pumped through a removal system, such as a Siltbuster, sand or cartridge filter, prior to discharge. Chemical sediment control is used on some construction sites around the United States and Europe. Another active treatment system design uses electrocoagulation to flocculate suspended particles in the stormwater, all states in the U. S. have laws requiring installation of erosion and sediment controls on construction sites of a specified size. Federal regulations require ESCs on sites 1 acre and larger, smaller sites which are part of a common plan of development are also required to have ESCs. In some states, non-contiguous sites under 1-acre are also required to have ESCs, for example, the State of Maryland requires ESCs on sites of 5,000 sq ft or more. The sediment controls must be installed before the beginning of land disturbance and must be maintained during the entire disturbance phase of construction. ”
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Landfill
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A landfill site is a site for the disposal of waste materials by burial and the oldest form of waste treatment. Historically, landfills have been the most common method of organized waste disposal, some landfills are also used for waste management purposes, such as the temporary storage, consolidation and transfer, or processing of waste material. A landfill also may refer to ground that has filled in with rocks instead of waste materials, so that it can be used for a specific purpose. Unless they are stabilized, these areas may experience severe shaking or soil liquefaction of the ground during a large earthquake, afterward, the waste collection vehicles use the existing road network on their way to the tipping face or working front, where they unload their contents. After loads are deposited, compactors or bulldozers can spread and compact the waste on the working face, before leaving the landfill boundaries, the waste collection vehicles may pass through a wheel-cleaning facility. If necessary, they return to the weighbridge for re-weighing without their load, the weighing process can assemble statistics on the daily incoming waste tonnage, which databases can retain for record keeping. In addition to trucks, some landfills may have equipment to handle railroad containers, the use of rail-haul permits landfills to be located at more remote sites, without the problems associated with many truck trips. Typically, in the face, the compacted waste is covered with soil or alternative materials daily. Alternative waste-cover materials include chipped wood or other waste, several sprayed-on foam products, chemically fixed bio-solids. Blankets can be lifted into place at night and then removed the day prior to waste placement. The space that is occupied daily by the waste and the cover material is called a daily cell. Waste compaction is critical to extending the life of the landfill, factors such as waste compressibility, waste-layer thickness and the number of passes of the compactor over the waste affect the waste densities. Landfills are often the most cost-efficient way to dispose of waste, in addition, landfill gas can be upgraded to natural gas—landfill gas utilization—which is a potential revenue stream. Another advantage is having a location for disposal that can be monitored. Landfills have the potential to cause a number of issues, infrastructure disruption, such as damage to access roads by heavy vehicles, may occur. Pollution of local roads and water courses from wheels on vehicles when they leave the landfill can be significant, pollution of the local environment, such as contamination of groundwater or aquifers or soil contamination may occur, as well. Extensive efforts are made to capture and treat leachate from landfills before it reaches groundwater aquifers, eventually, every landfill liner will leak, allowing the leachate to contaminate the groundwater. Installation of composite liners with flexible membrane and soil barrier is enforced by the EPA to ensure that leachate is withheld, rotting food and other decaying organic waste allows methane and carbon dioxide to seep out of the ground and up into the air
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Mining
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Mining is extraction of valuable minerals or other geological materials from the earth usually from an orebody, lode, vein, seam, reef or placer deposits. These deposits form a mineralized package that is of economic interest to the miner, ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain any material that cannot be grown through agricultural processes, Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Mining of stones and metal has been a human activity since pre-historic times, Mining operations usually create a negative environmental impact, both during the mining activity and after the mine has closed. Hence, most of the nations have passed regulations to decrease the impact. Work safety has long been a concern as well, and modern practices have significantly improved safety in mines, levels of metals recycling are generally low. Unless future end-of-life recycling rates are stepped up, some rare metals may become unavailable for use in a variety of consumer products, due to the low recycling rates, some landfills now contain higher concentrations of metal than mines themselves. Since the beginning of civilization, people have used stone, ceramics and, later and these were used to make early tools and weapons, for example, high quality flint found in northern France, southern England and Poland was used to create flint tools. Flint mines have been found in areas where seams of the stone were followed underground by shafts. The mines at Grimes Graves and Krzemionki are especially famous, other hard rocks mined or collected for axes included the greenstone of the Langdale axe industry based in the English Lake District. The oldest-known mine on archaeological record is the Lion Cave in Swaziland, at this site Paleolithic humans mined hematite to make the red pigment ochre. Mines of an age in Hungary are believed to be sites where Neanderthals may have mined flint for weapons. Ancient Egyptians mined malachite at Maadi, at first, Egyptians used the bright green malachite stones for ornamentations and pottery. Later, between 2613 and 2494 BC, large building projects required expeditions abroad to the area of Wadi Maghareh in order to secure minerals and other resources not available in Egypt itself. Quarries for turquoise and copper were found at Wadi Hammamat, Tura, Aswan and various other Nubian sites on the Sinai Peninsula. Mining in Egypt occurred in the earliest dynasties, the gold mines of Nubia were among the largest and most extensive of any in Ancient Egypt. These mines are described by the Greek author Diodorus Siculus, who mentions fire-setting as one used to break down the hard rock holding the gold. One of the complexes is shown in one of the earliest known maps, the miners crushed the ore and ground it to a fine powder before washing the powder for the gold dust
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Aquaculture
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Aquaculture, also known as aquafarming, is the farming of fish, crustaceans, molluscs, aquatic plants, algae, and other aquatic organisms. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, mariculture refers to aquaculture practiced in marine environments and in underwater habitats. According to the FAO, aquaculture Farming implies some form of intervention in the process to enhance production, such as regular stocking, feeding, protection from predators. Farming also implies individual or corporate ownership of the stock being cultivated, further, in current aquaculture practice, products from several pounds of wild fish are used to produce one pound of a piscivorous fish like salmon. Particular kinds of aquaculture include fish farming, shrimp farming, oyster farming, mariculture, algaculture, particular methods include aquaponics and integrated multi-trophic aquaculture, both of which integrate fish farming and plant farming. The indigenous Gunditjmara people in Victoria, Australia, may have raised eels as early as 6000 BC, Aquaculture was operating in China circa 2500 BC. When the waters subsided after river floods, some fish, mainly carp, were trapped in lakes, early aquaculturists fed their brood using nymphs and silkworm feces, and ate them. A fortunate genetic mutation of carp led to the emergence of goldfish during the Tang dynasty, japanese cultivated seaweed by providing bamboo poles and, later, nets and oyster shells to serve as anchoring surfaces for spores. Romans bred fish in ponds and farmed oysters in coastal lagoons before 100 CE, in central Europe, early Christian monasteries adopted Roman aquacultural practices. Aquaculture spread in Europe during the Middle Ages since away from the seacoasts, improvements in transportation during the 19th century made fresh fish easily available and inexpensive, even in inland areas, making aquaculture less popular. The 15th-century fishponds of the Trebon Basin in the Czech Republic are maintained as a UNESCO World Heritage Site, a remarkable example is a fish pond dating from at least 1,000 years ago, at Alekoko. Legend says that it was constructed by the mythical Menehune dwarf people, in first half of 18th century, German Stephan Ludwig Jacobi experimented with external fertilization of brown trouts and salmon. He wrote an article Von der künstlichen Erzeugung der Forellen und Lachse, by the latter decades of the 18th century, oyster farming had begun in estuaries along the Atlantic Coast of North America. The word aquaculture appeared in an 1855 newspaper article in reference to the harvesting of ice, in 1859, Stephen Ainsworth of West Bloomfield, New York, began experiments with brook trout. By 1864, Seth Green had established a commercial fish-hatching operation at Caledonia Springs, near Rochester, by 1866, with the involvement of Dr. W. W. Fletcher of Concord, Massachusetts, artificial fish hatcheries were under way in both Canada and the United States. When the Dildo Island fish hatchery opened in Newfoundland in 1889, the word aquaculture was used in descriptions of the hatcheries experiments with cod and lobster in 1890. By the 1920s, the American Fish Culture Company of Carolina, Rhode Island, during the 1940s, they had perfected the method of manipulating the day and night cycle of fish so that they could be artificially spawned year around. Californians harvested wild kelp and attempted to supply around 1900
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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
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Soil
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Soil is a mixture of minerals, organic matter, gases, liquids, and countless organisms that together support life on Earth. Soil is called the Skin of the Earth and interfaces with the lithosphere, the hydrosphere, the atmosphere, the term pedolith, used commonly to refer to the soil, literally translates ground stone. Soil consists of a phase of minerals and organic matter, as well as a porous phase that holds gases. Accordingly, soils are often treated as a system of solids, liquids. Soil is a product of the influence of climate, relief, organisms, Soil continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness soil has been considered as an ecosystem by soil ecologists. Most soils have a dry bulk density between 1.1 and 1.6 g/cm3, while the particle density is much higher. Little of the soil of planet Earth is older than the Pleistocene and none is older than the Cenozoic, Soil science has two basic branches of study, edaphology and pedology. Edaphology is concerned with the influence of soils on living things, pedology is focused on the formation, description, and classification of soils in their natural environment. In engineering terms, soil is referred to as regolith, or loose material that lies above the solid geology. Soil is commonly referred to as earth or dirt, technically, as soil resources serve as a basis for food security, the international community advocates its sustainable and responsible use through different types of soil governance. Soil is a component of the Earths ecosystem. The worlds ecosystems are impacted in far-reaching ways by the carried out in the soil, from ozone depletion and global warming, to rainforest destruction. Following the atmosphere, the soil is the next largest carbon reservoir on Earth, as the planet warms, soils will add carbon dioxide to the atmosphere due to its increased biological activity at higher temperatures. Thus, soil carbon losses likely have a positive feedback response to global warming. Since soil has a range of available niches and habitats. A gram of soil can contain billions of organisms, belonging to thousands of species, mostly microbial, Soil has a mean prokaryotic density of roughly 108 organisms per gram, whereas the ocean has no more than 107 procaryotic organisms per milliliter of seawater. Since plant roots need oxygen, ventilation is an important characteristic of soil and this ventilation can be accomplished via networks of interconnected soil pores, which also absorb and hold rainwater making it readily available for plant uptake
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Roman Empire
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Civil wars and executions continued, culminating in the victory of Octavian, Caesars adopted son, over Mark Antony and Cleopatra at the Battle of Actium in 31 BC and the annexation of Egypt. Octavians power was then unassailable and in 27 BC the Roman Senate formally granted him overarching power, the imperial period of Rome lasted approximately 1,500 years compared to the 500 years of the Republican era. The first two centuries of the empires existence were a period of unprecedented political stability and prosperity known as the Pax Romana, following Octavians victory, the size of the empire was dramatically increased. After the assassination of Caligula in 41, the senate briefly considered restoring the republic, under Claudius, the empire invaded Britannia, its first major expansion since Augustus. Vespasian emerged triumphant in 69, establishing the Flavian dynasty, before being succeeded by his son Titus and his short reign was followed by the long reign of his brother Domitian, who was eventually assassinated. The senate then appointed the first of the Five Good Emperors, the empire reached its greatest extent under Trajan, the second in this line. A period of increasing trouble and decline began with the reign of Commodus, Commodus assassination in 192 triggered the Year of the Five Emperors, of which Septimius Severus emerged victorious. The assassination of Alexander Severus in 235 led to the Crisis of the Third Century in which 26 men were declared emperor by the Roman Senate over a time span. It was not until the reign of Diocletian that the empire was fully stabilized with the introduction of the Tetrarchy, which saw four emperors rule the empire at once. This arrangement was unsuccessful, leading to a civil war that was finally ended by Constantine I. Constantine subsequently shifted the capital to Byzantium, which was renamed Constantinople in his honour and it remained the capital of the east until its demise. Constantine also adopted Christianity which later became the state religion of the empire. However, Augustulus was never recognized by his Eastern colleague, and separate rule in the Western part of the empire ceased to exist upon the death of Julius Nepos. The Eastern Roman Empire endured for another millennium, eventually falling to the Ottoman Turks in 1453, the Roman Empire was among the most powerful economic, cultural, political and military forces in the world of its time. It was one of the largest empires in world history, at its height under Trajan, it covered 5 million square kilometres. It held sway over an estimated 70 million people, at that time 21% of the entire population. Throughout the European medieval period, attempts were made to establish successors to the Roman Empire, including the Empire of Romania, a Crusader state. Rome had begun expanding shortly after the founding of the republic in the 6th century BC, then, it was an empire long before it had an emperor
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Fiber
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Fiber or fibre is a natural or synthetic substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials, the strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene. Natural fibers develop or occur in the shape, and include those produced by plants, animals. Plant fibers are employed in the manufacture of paper and textile, wood fiber, distinguished from vegetable fiber, is from tree sources. Forms include groundwood, lacebark, thermomechanical pulp, and bleached or unbleached kraft or sulfite pulps, animal fibers consist largely of particular proteins. Instances are silkworm silk, spider silk, sinew, catgut, wool, sea silk and hair such as wool, mohair and angora, fur such as sheepskin, rabbit, mink, fox, beaver. Mineral fibers include the asbestos group, asbestos is the only naturally occurring long mineral fiber. Six minerals have been classified as asbestos including chrysotile of the serpentine class, short, fiber-like minerals include wollastonite and palygorskite. Instances are collagen family of proteins, tendon, muscle proteins like actin, cell proteins like microtubules and many others, spider silk, sinew, man-made or chemical fibers are fibers whose chemical composition, structure, and properties are significantly modified during the manufacturing process. Man-made fibers consist of regenerated fibers and synthetic fibers, the earliest semi-synthetic fiber is the cellulose regenerated fiber, rayon. Most semi-synthetic fibers are cellulose regenerated fibers, cellulose fibers are a subset of man-made fibers, regenerated from natural cellulose. The cellulose comes from sources, rayon from tree wood fiber, Modal from beech trees, bamboo fiber from bamboo, seacell from seaweed. In the production of fibers, the cellulose is reduced to a fairly pure form as a viscous mass. Therefore, the process leaves few characteristics distinctive of the natural source material in the finished products. Some examples are, rayon bamboo fiber Lyocell, a brand of rayon Modal, historically, cellulose diacetate and -triacetate were classified under the term rayon, but are now considered distinct materials. Synthetic come entirely from materials such as petrochemicals, unlike those man-made fibers derived from such natural substances as cellulose or protein. Metallic fibers can be drawn from ductile metals such as copper, gold or silver and extruded or deposited from more brittle ones, such as nickel, carbon fibers are often based on oxydized and via pyrolysis carbonized polymers like PAN, but the end product is almost pure carbon. Silicon carbide fibers, where the polymers are not hydrocarbons but polymers
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Textile
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A textile or cloth is a flexible material consisting of a network of natural or artificial fibres. Yarn is produced by spinning raw fibres of wool, flax, cotton, hemp, Textiles are formed by weaving, knitting, crocheting, knotting, or felting. The words fabric and cloth are used in textile assembly trades as synonyms for textile, however, there are subtle differences in these terms in specialized usage. Textile refers to any material made of interlacing fibres, a fabric is a material made through weaving, knitting, spreading, crocheting, or bonding that may be used in production of further goods. Cloth may be used synonymously with fabric but is often a piece of fabric used for a specific purpose. The word textile is from Latin, from the adjective textilis, meaning woven, from textus, the word cloth derives from the Old English clað, meaning a cloth, woven or felted material to wrap around one, from Proto-Germanic kalithaz. The discovery of dyed flax fibres in a cave in the Republic of Georgia dated to 34,000 BCE suggests textile-like materials were made even in prehistoric times. The production of textiles is a craft whose speed and scale of production has been altered almost beyond recognition by industrialization, however, for the main types of textiles, plain weave, twill, or satin weave, there is little difference between the ancient and modern methods. Textiles have an assortment of uses, the most common of which are for clothing and for such as bags. In the household they are used in carpeting, upholstered furnishings, window shades, towels, coverings for tables, beds, and other flat surfaces, in the workplace they are used in industrial and scientific processes such as filtering. Textiles are used in traditional crafts such as sewing, quilting. Textiles for industrial purposes, and chosen for other than their appearance, are commonly referred to as technical textiles. Technical textiles include textile structures for applications, medical textiles, geotextiles, agrotextiles. In all these applications stringent performance requirements must be met, woven of threads coated with zinc oxide nanowires, laboratory fabric has been shown capable of self-powering nanosystems using vibrations created by everyday actions like wind or body movements. Fashion designers commonly rely on textile designs to set their fashion collections apart from others, armani, the late Gianni Versace, and Emilio Pucci can be easily recognized by their signature print driven designs. Textiles can be made from many materials and these materials come from four main sources, animal, plant, mineral, and synthetic. In the past, all textiles were made from natural fibres, including plant, animal, in the 20th century, these were supplemented by artificial fibres made from petroleum. Textiles are made in various strengths and degrees of durability, from the finest gossamer to the sturdiest canvas, microfibre refers to fibres made of strands thinner than one denier
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Vegetation
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Vegetation is assemblages of plant species and the ground cover they provide. It is a term, without specific reference to particular taxa, life forms, structure, spatial extent. It is broader than the flora which refers to species composition. Perhaps the closest synonym is plant community, but vegetation can, primeval redwood forests, coastal mangrove stands, sphagnum bogs, desert soil crusts, roadside weed patches, wheat fields, cultivated gardens and lawns, all are encompassed by the term vegetation. The vegetation type is defined by characteristic dominant species, or an aspect of the assemblage. The contemporary use of vegetation approximates that of ecologist Frederic Clements term earth cover, Natural vegetation refers to plant life undisturbed by humans in its growth and which is controlled by the climatic conditions of that region. The distinction between vegetation and flora was first made by Jules Thurmann, prior to this, the two terms were used indiscriminately, and still are in some contexts. Augustin de Candolle also made a distinction, but he used the terms station and habitation. Later, the concept of vegetation would influence the usage of the term biome, other concepts similar to vegetation are physiognomy of vegetation and formation. Departing from Linnean taxonomy, Humboldt established a new science, dividing plant geography between taxonomists who studied plants as taxa and geographers who studied plants as vegetation. The physiognomic approach in the study of vegetation is common among biogeographers working on vegetation on a world scale, the concept vegetation type is more ambiguous. For some authors, it includes, besides physiognomy, floristic, furthermore, the phytosociological approach in the study of vegetation relies upon a fundamental unit, the plant association, which is defined upon flora. An influential, clear and simple scheme for types of vegetation was produced by Wagner & von Sydow. Like all the systems, plant communities are temporally and spatially dynamic. Dynamism in vegetation is defined primarily as changes in species composition and/or vegetation structure, temporally, a large number of processes or events can cause change, but for sake of simplicity they can be categorized roughly as either abrupt or gradual. Abrupt changes are referred to as disturbances, these include things like wildfires, high winds, landslides, floods, avalanches. Their causes are external to the community—they are natural processes occurring independently of the natural processes of the community. Such events can change vegetation structure and composition very quickly and for time periods
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Egyptian pyramids
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The Egyptian pyramids are ancient pyramid-shaped masonry structures located in Egypt. As of November 2008, sources cite either 118 or 138 as the number of identified Egyptian pyramids, most were built as tombs for the countrys pharaohs and their consorts during the Old and Middle Kingdom periods. The earliest known Egyptian pyramids are found at Saqqara, northwest of Memphis, the earliest among these is the Pyramid of Djoser which was built during the third dynasty. This pyramid and its surrounding complex were designed by the architect Imhotep, the most famous Egyptian pyramids are those found at Giza, on the outskirts of Cairo. Several of the Giza pyramids are counted among the largest structures ever built, the Pyramid of Khufu at Giza is the largest Egyptian pyramid. It is the one of the Seven Wonders of the Ancient World still in existence. By the time of the Early Dynastic Period, those with sufficient means were buried in bench-like structures known as mastabas, the second historically-documented Egyptian pyramid is attributed to the architect Imhotep, who planned what Egyptologists believe to be a tomb for the pharaoh Djoser. Imhotep is credited with being the first to conceive the notion of stacking mastabas on top of each other, the result was the Pyramid of Djoser, which was designed to serve as a gigantic stairway by which the soul of the deceased pharaoh could ascend to the heavens. Such was the importance of Imhoteps achievement that he was deified by later Egyptians, the most prolific pyramid-building phase coincided with the greatest degree of absolutist rule. It was during this time that the most famous pyramids, the Giza pyramid complex, were built. Long after the end of Egypts own pyramid-building period, a burst of pyramid-building occurred in what is present-day Sudan, al-Aziz Uthman tried to destroy the Giza pyramid complex. He gave up after damaging the Pyramid of Menkaure because the task proved too huge, the shape of Egyptian pyramids is thought to represent the primordial mound from which the Egyptians believed the earth was created. Pyramids were often named in ways that referred to solar luminescence. For example, the name of the Bent Pyramid at Dahshur The Southern Shining Pyramid. While it is agreed that pyramids were burial monuments, there is continued disagreement on the particular theological principles that might have given rise to them. One suggestion is that they were designed as a type of resurrection machine, the Egyptians believed the dark area of the night sky around which the stars appear to revolve was the physical gateway into the heavens. One of the shafts that extend from the main burial chamber through the entire body of the Great Pyramid points directly towards the center of this part of the sky. This suggests the pyramid may have designed to serve as a means to magically launch the deceased pharaohs soul directly into the abode of the gods
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Egypt
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Egypt, officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia by a land bridge formed by the Sinai Peninsula. Egypt is a Mediterranean country bordered by the Gaza Strip and Israel to the northeast, the Gulf of Aqaba to the east, the Red Sea to the east and south, Sudan to the south, and Libya to the west. Across the Gulf of Aqaba lies Jordan, and across from the Sinai Peninsula lies Saudi Arabia, although Jordan and it is the worlds only contiguous Afrasian nation. Egypt has among the longest histories of any country, emerging as one of the worlds first nation states in the tenth millennium BC. Considered a cradle of civilisation, Ancient Egypt experienced some of the earliest developments of writing, agriculture, urbanisation, organised religion and central government. One of the earliest centres of Christianity, Egypt was Islamised in the century and remains a predominantly Muslim country. With over 92 million inhabitants, Egypt is the most populous country in North Africa and the Arab world, the third-most populous in Africa, and the fifteenth-most populous in the world. The great majority of its people live near the banks of the Nile River, an area of about 40,000 square kilometres, the large regions of the Sahara desert, which constitute most of Egypts territory, are sparsely inhabited. About half of Egypts residents live in areas, with most spread across the densely populated centres of greater Cairo, Alexandria. Modern Egypt is considered to be a regional and middle power, with significant cultural, political, and military influence in North Africa, the Middle East and the Muslim world. Egypts economy is one of the largest and most diversified in the Middle East, Egypt is a member of the United Nations, Non-Aligned Movement, Arab League, African Union, and Organisation of Islamic Cooperation. Miṣr is the Classical Quranic Arabic and modern name of Egypt. The name is of Semitic origin, directly cognate with other Semitic words for Egypt such as the Hebrew מִצְרַיִם, the oldest attestation of this name for Egypt is the Akkadian
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Wood
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Wood is a porous and fibrous structural tissue found in the stems and roots of trees, and other woody plants. It is a material, a natural composite of cellulose fibers which are strong in tension embedded in a matrix of lignin which resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, in a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots, Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber. In 2005, the stock of forests worldwide was about 434 billion cubic meters. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy, in 1991 approximately 3.5 billion cubic meters of wood were harvested. Dominant uses were for furniture and building construction, a 2011 discovery in the Canadian province of New Brunswick discovered the earliest known plants to have grown wood, approximately 395 to 400 million years ago. Wood can be dated by carbon dating and in species by dendrochronology to make inferences about when a wooden object was created. People have used wood for millennia for many purposes, primarily as a fuel or as a material for making houses, tools, weapons, furniture, packaging, artworks. Constructions using wood date back ten thousand years, buildings like the European Neolithic long house were made primarily of wood. Recent use of wood has changed by the addition of steel. The year-to-year variation in tree-ring widths and isotopic abundances gives clues to the climate at that time. This process is known as growth, it is the result of cell division in the vascular cambium, a lateral meristem. These cells then go on to form thickened secondary cell walls, composed mainly of cellulose, hemicellulose, if the distinctiveness between seasons is annual, these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are likely to be indistinct or absent, if the bark of the tree has been removed in a particular area, the rings will likely be deformed as the plant overgrows the scar. It is usually lighter in color than that near the portion of the ring. The outer portion formed later in the season is known as the latewood or summerwood. However, there are differences, depending on the kind of wood
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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
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Biodegradation
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Biodegradation is the disintegration of materials by bacteria, fungi, or other biological means. Although often conflated, biodegradable is distinct in meaning from compostable, while biodegradable simply means to be consumed by microorganisms, compostable makes the specific demand that the object break down under composting conditions. Organic material can be degraded aerobically with oxygen, or anaerobically, biosurfactant, an extracellular surfactant secreted by microorganisms, enhances the biodegradation process. Biodegradable matter is generally organic material serves as a nutrient for microorganisms. Microorganisms are so numerous and diverse that, a range of compounds are biodegraded, including hydrocarbons, polychlorinated biphenyls, polyaromatic hydrocarbons. Decomposition of biodegradable substances may include both biological and abiotic steps, in practice, almost all chemical compounds and materials are subject to biodegradation, the key is the relative rates of such processes - minutes, days, years, centuries. A number of factors determine the rate of organic compounds. Salient factors include light, water and oxygen, temperature is also important because chemical reactions proceed more quickly at higher temperatures. The degradation rate of organic compounds is limited by their bioavailability. Compounds must be released into solution before organisms can degrade them, Biodegradability can be measured in a number of ways. Respirometry tests can be used for aerobic microbes, first one places a solid waste sample in a container with microorganisms and soil, and then aerate the mixture. Over the course of days, microorganisms digest the sample bit by bit. Biodegradability can also be measured by anaerobic microbes and the amount of methane or alloy that they are able to produce, in formal scientific literature, the process is termed bio-remediation. In advanced societies, laundry detergents are based on linear alkylbenzenesulfonates, branched alkybenzenesulfonates, used in former times, were abandoned because they biodegrade too slowly. Plastics biodegrade at highly variable rates, pVC-based plumbing is specifically selected for handing sewage because PVC biodegrades very slowly. Some packaging materials on the hand are being developed that would degrade readily upon exposure to the environment. A prominent example is poly-3-hydroxybutyrate, the renewably derived polylactic acid, others are the cellulose-based cellulose acetate and celluloid. Under low oxygen conditions biodegradable plastics break down slower and with the production of methane, the breakdown process is accelerated in a dedicated compost heap
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Microorganism
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A microorganism or microbe is a microscopic organism, which may be single-celled or multicellular. The study of microorganisms is called microbiology, a subject that began with the discovery of microorganisms in 1674 by Antonie van Leeuwenhoek, microorganisms are very diverse and include all bacteria, archaea and most protozoa. This group also contains some fungi, algae, and some such as rotifers. Many macroscopic animals and plants have microscopic juvenile stages, some microbiologists classify viruses and viroids as microorganisms, but others consider these as nonliving. In July 2016, scientists identified a set of 355 genes from the last universal ancestor of all life, including microorganisms. Microorganisms, under certain test conditions, have observed to thrive in the vacuum of outer space. Microorganisms likely far outweigh all other living things combined, the mass of prokaryote microorganisms including the bacteria and archaea may be as much as 0.8 trillion tons of carbon, out of the total biomass of between 1 and 4 trillion tons. Microorganisms appear to thrive in the Mariana Trench, the deepest spot in the Earths oceans, in August 2014, scientists confirmed the existence of microorganisms living 800 m below the ice of Antarctica. According to one researcher, You can find microbes everywhere — theyre extremely adaptable to conditions, microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a part of the nitrogen cycle. Microorganisms are also exploited in biotechnology, both in food and beverage preparation, and in modern technologies based on genetic engineering. A small proportion of microorganisms are pathogenic, causing disease and even death in plants, Robert Hooke coined the term cell after viewing plant cells under his microscope. Antonie Van Leeuwenhoek was one of the first people to observe microorganisms in 1673, later, in the 19th century, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In 1876 Robert Koch discovered that microorganisms cause diseases, single-celled microorganisms were the first forms of life to develop on Earth, approximately 3–4 billion years ago. Further evolution was slow, and for about 3 billion years in the Precambrian eon, so, for most of the history of life on Earth, the only forms of life were microorganisms. Bacteria, algae and fungi have been identified in amber that is 220 million years old, microorganisms tend to have a relatively fast rate of evolution. Most microorganisms can reproduce rapidly, and bacteria are able to freely exchange genes through conjugation, transformation and transduction. This rapid evolution is important in medicine, as it has led to the development of multidrug resistant pathogenic bacteria, superbugs, the possible existence of microorganisms was discussed for many centuries before their discovery in the 17th century
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United States
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Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
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Europe
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Europe is a continent that comprises the westernmost part of Eurasia. Europe is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, yet the non-oceanic borders of Europe—a concept dating back to classical antiquity—are arbitrary. Europe covers about 10,180,000 square kilometres, or 2% of the Earths surface, politically, Europe is divided into about fifty sovereign states of which the Russian Federation is the largest and most populous, spanning 39% of the continent and comprising 15% of its population. Europe had a population of about 740 million as of 2015. Further from the sea, seasonal differences are more noticeable than close to the coast, Europe, in particular ancient Greece, was the birthplace of Western civilization. The fall of the Western Roman Empire, during the period, marked the end of ancient history. Renaissance humanism, exploration, art, and science led to the modern era, from the Age of Discovery onwards, Europe played a predominant role in global affairs. Between the 16th and 20th centuries, European powers controlled at times the Americas, most of Africa, Oceania. The Industrial Revolution, which began in Great Britain at the end of the 18th century, gave rise to economic, cultural, and social change in Western Europe. During the Cold War, Europe was divided along the Iron Curtain between NATO in the west and the Warsaw Pact in the east, until the revolutions of 1989 and fall of the Berlin Wall. In 1955, the Council of Europe was formed following a speech by Sir Winston Churchill and it includes all states except for Belarus, Kazakhstan and Vatican City. Further European integration by some states led to the formation of the European Union, the EU originated in Western Europe but has been expanding eastward since the fall of the Soviet Union in 1991. The European Anthem is Ode to Joy and states celebrate peace, in classical Greek mythology, Europa is the name of either a Phoenician princess or of a queen of Crete. The name contains the elements εὐρύς, wide, broad and ὤψ eye, broad has been an epithet of Earth herself in the reconstructed Proto-Indo-European religion and the poetry devoted to it. For the second part also the divine attributes of grey-eyed Athena or ox-eyed Hera. The same naming motive according to cartographic convention appears in Greek Ανατολή, Martin Litchfield West stated that phonologically, the match between Europas name and any form of the Semitic word is very poor. Next to these there is also a Proto-Indo-European root *h1regʷos, meaning darkness. Most major world languages use words derived from Eurṓpē or Europa to refer to the continent, in some Turkic languages the originally Persian name Frangistan is used casually in referring to much of Europe, besides official names such as Avrupa or Evropa
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Paris
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Paris is the capital and most populous city of France. It has an area of 105 square kilometres and a population of 2,229,621 in 2013 within its administrative limits, the agglomeration has grown well beyond the citys administrative limits. By the 17th century, Paris was one of Europes major centres of finance, commerce, fashion, science, and the arts, and it retains that position still today. The aire urbaine de Paris, a measure of area, spans most of the Île-de-France region and has a population of 12,405,426. It is therefore the second largest metropolitan area in the European Union after London, the Metropole of Grand Paris was created in 2016, combining the commune and its nearest suburbs into a single area for economic and environmental co-operation. Grand Paris covers 814 square kilometres and has a population of 7 million persons, the Paris Region had a GDP of €624 billion in 2012, accounting for 30.0 percent of the GDP of France and ranking it as one of the wealthiest regions in Europe. The city is also a rail, highway, and air-transport hub served by two international airports, Paris-Charles de Gaulle and Paris-Orly. Opened in 1900, the subway system, the Paris Métro. It is the second busiest metro system in Europe after Moscow Metro, notably, Paris Gare du Nord is the busiest railway station in the world outside of Japan, with 262 millions passengers in 2015. In 2015, Paris received 22.2 million visitors, making it one of the top tourist destinations. The association football club Paris Saint-Germain and the rugby union club Stade Français are based in Paris, the 80, 000-seat Stade de France, built for the 1998 FIFA World Cup, is located just north of Paris in the neighbouring commune of Saint-Denis. Paris hosts the annual French Open Grand Slam tennis tournament on the red clay of Roland Garros, Paris hosted the 1900 and 1924 Summer Olympics and is bidding to host the 2024 Summer Olympics. The name Paris is derived from its inhabitants, the Celtic Parisii tribe. Thus, though written the same, the name is not related to the Paris of Greek mythology. In the 1860s, the boulevards and streets of Paris were illuminated by 56,000 gas lamps, since the late 19th century, Paris has also been known as Panam in French slang. Inhabitants are known in English as Parisians and in French as Parisiens and they are also pejoratively called Parigots. The Parisii, a sub-tribe of the Celtic Senones, inhabited the Paris area from around the middle of the 3rd century BC. One of the areas major north-south trade routes crossed the Seine on the île de la Cité, this place of land and water trade routes gradually became a town
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Hydraulic engineering
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Hydraulic engineering as a sub-discipline of civil engineering is concerned with the flow and conveyance of fluids, principally water and sewage. One feature of these systems is the use of gravity as the motive force to cause the movement of the fluids. This area of engineering is intimately related to the design of bridges, dams, channels, canals, and levees. Hydraulic engineering is the application of the principles of mechanics to problems dealing with the collection, storage, control, transport, regulation, measurement. Before beginning a hydraulic engineering project, one must figure out how water is involved. The hydraulic engineer is concerned with the transport of sediment by the river, the interaction of the water with its boundary. Fundamentals of Hydraulic Engineering defines hydrostatics as the study of fluids at rest, in a fluid at rest, there exists a force, known as pressure, that acts upon the fluids surroundings. This pressure, measured in N/m2, is not constant throughout the body of fluid, pressure, p, in a given body of fluid, increases with an increase in depth. Four basic devices for measurement are a piezometer, manometer, differential manometer, Bourdon gauge. As Prasuhn states, On undisturbed submerged bodies, pressure acts along all surfaces of a body in a liquid and this reaction is known as equilibrium. More advanced applications of pressure are that on plane surfaces, curved surfaces, dams, the main difference between an ideal fluid and a real fluid is that for ideal flow p1 = p2 and for real flow p1 > p2. Ideal fluid is incompressible and has no viscosity, ideal fluid is only an imaginary fluid as all fluids that exist have some viscosity. A viscous fluid will deform continuously under a force, whereas an ideal fluid doesnt deform. The various effects of disturbance on a flow are stable, transition. For an ideal fluid, Bernoullis equation holds along streamlines, as the flow comes into contact with the plate, the layer of fluid actually adheres to a solid surface. There is then a considerable shearing action between the layer of fluid on the surface and the second layer of fluid. The second layer is forced to decelerate, creating a shearing action with the third layer of fluid. As the fluid passes further along the plate, the zone in which shearing action occurs tends to spread further outwards and this zone is known as the boundary layer
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Bentonite clay
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Bentonite is an absorbent aluminium phyllosilicate clay consisting mostly of montmorillonite. It was named by Wilbur C, knight in 1898 after the Cretaceous Benton Shale near Rock River, Wyoming. The different types of bentonite are each named after the dominant element, such as potassium, sodium, calcium. Experts debate a number of problems with the classification of bentonite clays. Bentonite usually forms from weathering of volcanic ash, most often in the presence of water, however, the term bentonite, as well as a similar clay called tonstein, has been used to describe clay beds of uncertain origin. For industrial purposes, two classes of bentonite exist, sodium and calcium bentonite. In stratigraphy and tephrochronology, completely devitrified ash-fall beds are commonly referred to as K-bentonites when the dominant clay species is illite, in addition to montmorillonite and illite another common clay species that is sometimes dominant is kaolinite. Kaolinite-dominated clays are referred to as tonsteins and are typically associated with coal. Sodium bentonite expands when wet, absorbing as much as several times its dry mass in water, because of its excellent colloidal properties, it is often used in drilling mud for oil and gas wells and boreholes for geotechnical and environmental investigations. The property of swelling also makes sodium bentonite useful as a sealant, since it provides a self-sealing and it is used to line the base of landfills, for example. Various surface modifications to sodium bentonite improve some rheological or sealing performance in applications, for example. Calcium bentonite is a useful adsorbent of ions in solution, as well as fats and it is the main active ingredient of fullers earth, probably one of the earliest industrial cleaning agents. Calcium bentonite may be converted to sodium bentonite to exhibit many of sodium bentonites properties by an ion exchange process, some properties, such as viscosity and fluid loss of suspensions, of sodium-beneficiated calcium bentonite may not be fully equivalent to those of natural sodium bentonite. For example, residual calcium carbonates may result in performance of the bentonite in geosynthetic liners. Also known as potash bentonite or K-bentonite, potassium bentonite is a potassium-rich illitic clay formed from alteration of volcanic ash, the main uses of bentonite are for drilling mud, binder, purifier, absorbent, and as a groundwater barrier. As of around 1990, almost half of the US production of bentonite was used for drilling mud, bentonite is used in drilling fluids to lubricate and cool the cutting tools, to remove cuttings, and to help prevent blowouts. Much of bentonites usefulness in the drilling and geotechnical engineering industry comes from its rheological properties. Relatively small quantities of bentonite suspended in water form a viscous, most often, bentonite suspensions are also thixotropic, although rare cases of rheopectic behavior have also been reported
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Plastic
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Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and can be molded into solid objects. Plastics are typically organic polymers of high mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood, stone, horn and bone, leather, paper, metal, glass, and ceramic, in most of their former uses. In developed countries, about a third of plastic is used in packaging, other uses include automobiles, furniture, and toys. In the developing world, the ratios may be different - for example, the worlds first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term plastics. Toward the end of the century, one approach to this problem was met with wide efforts toward recycling, the word plastic is derived from the Greek πλαστικός meaning capable of being shaped or molded, from πλαστός meaning molded. The common word plastic should not be confused with the technical adjective plastic, used for insulating parts in electrical fixtures, paper laminated products, thermally insulation foams. Problems include the probability of moldings naturally being dark colors, One of the most expensive commercial polymers. It forms the basis of artistic and commercial acrylic paints when suspended in water with the use of other agents, polytetrafluoroethylene – Heat-resistant, low-friction coatings, used in things like non-stick surfaces for frying pans, plumbers tape and water slides. It is more known as Teflon. Urea-formaldehyde – One of the aminoplasts and used as an alternative to phenolics. Used as an adhesive and electrical switch housings. Early plastics were bio-derived materials such as egg and blood proteins, in 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines. Treated cattle horns were used as windows for lanterns in the Middle Ages, materials that mimicked the properties of horns were developed by treating milk-proteins with lye. In the 1800s, as industrial chemistry developed during the Industrial Revolution, the development of plastics also accelerated with Charles Goodyears discovery of vulcanization to thermoset materials derived from natural rubber. Parkesine is considered the first man-made plastic, the plastic material was patented by Alexander Parkes, In Birmingham, UK in 1856. It was unveiled at the 1862 Great International Exhibition in London, parkesine won a bronze medal at the 1862 Worlds fair in London
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Leachate
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A leachate is any liquid that, in the course of passing through matter, extracts soluble or suspended solids, or any other component of the material through which it has passed. It is most commonly used in the context of land-filling of putrescible or industrial waste, leachate from a landfill varies widely in composition depending on the age of the landfill and the type of waste that it contains. It usually contains both dissolved and suspended material, the generation of leachate is caused principally by precipitation percolating through waste deposited in a landfill. Once in contact with decomposing solid waste, the water becomes contaminated. The use of linings is now mandatory within the United States, Australia, in addition, most toxic and difficult materials are now specifically excluded from landfilling. When water percolates through waste, it promotes and assists the process of decomposition by bacteria and these processes in turn release by-products of decomposition and rapidly use up any available oxygen, creating an anoxic environment. The decomposition processes themselves release more water, which adds to the volume of leachate, leachate also reacts with materials that are not prone to decomposition themselves, such as fire ash, cement-based building materials and gypsum-based materials changing the chemical composition. The physical appearance of leachate when it emerges from a landfill site is a strongly odoured black-. The smell is acidic and offensive and may be very pervasive because of hydrogen-, nitrogen-, in older landfills and those with no membrane between the waste and the underlying geology, leachate is free to leave the waste and flow directly into the groundwater. In such cases, high concentrations of leachate are often found in nearby springs, as leachate first emerges it can be black in colour, anoxic, and possibly effervescent, with dissolved and entrained gases. As it becomes oxygenated it tends to brown or yellow because of the presence of iron salts in solution. It also quickly develops a bacterial flora often comprising substantial growths of Sphaerotilus natans, in the UK, in the late 1960s, central Government policy was to ensure new landfill sites were being chosen with permeable underlying geological strata to avoid the build-up of leachate. This policy was dubbed dilute and disperse, proposed landfill locations also had to be justified not only by geography but also scientifically. Many European countries decided to select sites in groundwater-free clay geological conditions or to require that the site have an engineered lining. In the wake of European advancements, the United States increased its development of leachate retaining and this quickly led from lining in principle to the use of multiple lining layers in all landfills. There are many components to a system including pumps, manholes, discharge lines. However, there are four main components which govern the overall efficiency of the system and these four elements are liners, filters, pumps and sumps. Natural and synthetic liners may be utilized as both a collection device and as a means for isolating leachate within the fill to protect the soil, the chief concern is the ability of a liner to maintain integrity and impermeability over the life of the landfill
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Silt fence
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Silt fences are widely used on construction sites in North America and elsewhere, due to their low cost and simple design. However, their effectiveness in controlling sediment can be limited, due to problems with installation, proper placement. A typical fence consists of a piece of synthetic filter fabric stretched between a series of wooden or metal fence stakes along a contour level. The design/placement of the fence should create a pooling of runoff. Water can seep through the silt fence fabric, but the fabric often becomes blocked off with fine soil particles, a few hours after a storm event, the fabric can be disturbed in order to dislodge the fines, and allow clean water to flow through. The fence is not designed to concentrate or channel stormwater, the fence is installed on a site before soil disturbance begins, and is placed down-slope from the disturbance area. Sediment is captured by silt fences primarily through ponding of water and settling, sand and silt tends to clog the fabric, and then the sediments settle in the temporary pond. Some government jurisdictions in the United States recommend or require the use of a fence, sometimes called a super silt fence or an enhanced silt fence. This design uses filter fabric reinforced by a mesh or chain link fence. However, an installation of a super silt fence can create an inadvertent sediment basin when the filter fabric becomes clogged. This typically causes flooding and increased downstream pollution, some state agencies recommend an installation technique called static slicing as an improved method for ensuring effectiveness and longevity of a silt fence system on a construction site. This step is followed by mechanical soil compaction, setting of fence posts, silt fence fabrics tested in laboratory settings have shown to be effective at trapping sediment particles. Although there have been few field tests of silt fences installed at construction sites, other studies and articles about silt fence usage and practice document problems with installation and maintenance, implying poor performance. Silt fences may perform poorly for a variety of reasons, including location, improper installation and lack of maintenance—fabric falling off of the posts. A silt fence top-full of sediment may need maintenance/replacement, but it is a huge success, the fabric may become damaged with holes and tears if construction materials are stored next to or on top of the fence. During various phases of construction at a site, a fence may be removed relocated and reinstalled multiple times. It may be difficult to maintain effectiveness of a silt fence under such operating conditions, location of fences in areas with high flows may lead to fence failures when the installation is not adequately back-filled and properly compacted, and/or the post-spacing is inadequate
. PMID 27877792.
