1.
Groundwater pollution
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Groundwater pollution occurs when pollutants are released to the ground and make their way down into groundwater. The pollutant creates a contaminant plume within an aquifer, movement of water and dispersion within the aquifer spreads the pollutant over a wider area. The movement of the plume, called a front, may be analyzed through a hydrological transport model or groundwater model. Analysis of groundwater pollution may focus on soil characteristics and site geology, hydrogeology, hydrology, pollution can also occur from naturally occurring contaminants, such as arsenic or fluoride. Using polluted groundwater causes hazards to health through poisoning or the spread of disease. Different mechanisms have influence on the transport of pollutants, e. g. diffusion, adsorption, precipitation, decay, the interaction of groundwater contamination with surface waters is analyzed by use of hydrology transport models. Contaminants found in cover a broad range of physical, inorganic chemical, organic chemical, bacteriological. Principally, many of the pollutants that play a role in surface water pollution may also be found in polluted groundwater. Arsenic and fluoride have been recognized by the World Health Organization as the most serious inorganic contaminants in drinking-water on a worldwide basis, the metalloid arsenic can occur naturally in groundwater, as seen most frequently in Asia, including in China, India and Bangladesh. In the Ganges Plain of northern India and Bangladesh severe contamination of groundwater by naturally occurring arsenic affects 25% of water wells in the shallower of two regional aquifers, arsenic in groundwater can also be present where there are mining operations or mine waste dumps that will leach arsenic. Natural fluoride in groundwater is of growing concern as deeper groundwater is being used, fluoride can especially be released from acidic volcanic rocks and dispersed volcanic ash when water hardness is low. Pathogens contained in feces can lead to groundwater pollution when they are given the opportunity to reach the groundwater, groundwater that is contaminated with pathogens can lead to fatal fecal-oral transmission of diseases. Nitrate is the most common contaminant in the world’s groundwater. In some low-income countries nitrate levels in groundwater are extremely high and it is also stable under high oxygen conditions. Nitrate levels above 10 mg/L in groundwater can cause blue baby syndrome, Drinking water quality standards in the European Union stipulate less than 50 mg/L for nitrate in drinking water. However, the linkages between nitrates in drinking water and blue baby syndrome have been disputed in other studies, the syndrome outbreaks might be due to other factors than elevated nitrate concentrations in drinking water. Elevated nitrate levels in groundwater can be caused by on-site sanitation and it can therefore have an urban or agricultural origin. Volatile organic compounds are a dangerous contaminant of groundwater and they are generally introduced to the environment through careless industrial practices
2.
Arsenic
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Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in minerals, usually in combination with sulfur and metals. It has various allotropes, but only the form is important to industry. The primary use of arsenic is in alloys of lead. Arsenic is a common dopant in semiconductor electronic devices. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, a few species of bacteria are able to use arsenic compounds as respiratory metabolites. Trace quantities of arsenic are a dietary element in rats, hamsters, goats, chickens. However, arsenic poisoning occurs in multicellular life if quantities are larger than needed, Arsenic contamination of groundwater is a problem that affects millions of people across the world. The three most common allotropes are metallic gray, yellow, and black arsenic, with gray being the most common. Gray arsenic adopts a structure consisting of many interlocked, ruffled, six-membered rings. Because of weak bonding between the layers, gray arsenic is brittle and has a relatively low Mohs hardness of 3.5. Nearest and next-nearest neighbors form an octahedral complex, with the three atoms in the same double-layer being slightly closer than the three atoms in the next. This relatively close packing leads to a density of 5.73 g/cm3. Gray arsenic is a semimetal, but becomes a semiconductor with a bandgap of 1. 2–1.4 eV if amorphized, gray arsenic is also the most stable form. Yellow arsenic is soft and waxy, and somewhat similar to tetraphosphorus, both have four atoms arranged in a tetrahedral structure in which each atom is bound to each of the other three atoms by a single bond. This unstable allotrope, being molecular, is the most volatile, least dense, solid yellow arsenic is produced by rapid cooling of arsenic vapor, As 4. It is rapidly transformed into gray arsenic by light, the yellow form has a density of 1.97 g/cm3. Black arsenic is similar in structure to red phosphorus, black arsenic can also be formed by cooling vapor at around 100–220 °C
3.
Groundwater
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Groundwater is the water present beneath Earths surface in soil pore spaces and in the fractures of rock formations. A unit of rock or a deposit is called an aquifer when it can yield a usable quantity of water. The depth at which pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the naturally, natural discharge often occurs at springs and seeps. Groundwater is also withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, Groundwater is hypothesized to provide lubrication that can possibly influence the movement of faults. It is likely that much of Earths subsurface contains some water, Groundwater may not be confined only to Earth. The formation of some of the landforms observed on Mars may have influenced by groundwater. There is also evidence that water may also exist in the subsurface of Jupiters moon Europa. Groundwater is often cheaper, more convenient and less vulnerable to pollution than surface water, therefore, it is commonly used for public water supplies. For example, groundwater provides the largest source of water storage in the United States. Underground reservoirs contain far more water than the capacity of all surface reservoirs and lakes in the US, many municipal water supplies are derived solely from groundwater. Polluted groundwater is less visible, but more difficult to clean up, than pollution in rivers, Groundwater pollution most often results from improper disposal of wastes on land. An aquifer is a layer of substrate that contains and transmits groundwater. When water can flow directly between the surface and the zone of an aquifer, the aquifer is unconfined. The deeper parts of unconfined aquifers are more saturated since gravity causes water to flow downward. The upper level of this layer of an unconfined aquifer is called the water table or phreatic surface. Below the water table, where in general all pore spaces are saturated with water, is the phreatic zone, substrate with low porosity that permits limited transmission of groundwater is known as an aquitard
4.
Tubewell
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A tube well is a type of water well in which a long 100–200 millimetres wide stainless steel tube or pipe is bored into an underground aquifer. The lower end is fitted with a strainer, and a pump water for irrigation. The required depth of the well depends on the depth of the water table, a small reservoir of water is made at the outlet of the tube well. This reservoir is used for different usage of water by the local population, in the past, the pump was typically driven by a large diesel engine. Today electric motors are commonly used on account of economy. The tube well casing houses the inlet, cylinder, piston valves, casing to support the external surfaces of the borehole against collapse may be needed, either temporarily or permanently, and is often made of PVC pipe, which is both cheap and inert. Seepage down the well bore is prevented by the sanitary seal. Seepage from the ground above the aquifer is excluded by the lengths of plain casing, water to be pumped is admitted through slots in the lower lengths of casing. Water abstracted from aquifers in relatively soft ground usually contains sand or silt particles, methods of preventing these particles from reaching the pump are of two general types, screening and sand/gravel packing. The drawing shows slots in the PVC casing which can be cut on site, using a hacksaw and it is sealed The drawing shows graded sand and gravel, which is placed from the top of the borehole. More compact, pre-bonded, packs of sand and/or gravel are available commercially, high concentrations of arsenic occur naturally in the soil in some areas of Bangladesh. The water table is close to the surface. Able to irrigate a larger area. More reliable during periods of drought when water dries up
5.
Ganges Delta
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The Ganges-Brahmaputra Delta in Bangladesh and in West Bengal is a river delta in the Bengal region of the Indian subcontinent, consisting of Bangladesh and the Indian state of West Bengal. It is the worlds largest delta, and empties into the Bay of Bengal and it is also one of the most fertile regions in the world, thus earning the nickname The Green Delta. The delta stretches from the Hooghly River on the west to the Meghna River on the east and it is approximately 354 km across at the Bay of Bengal. Kolkata and Haldia in India and Mongla and Chittagong in Bangladesh are the seaports of the delta. A number of rivers flow through the Brahmaputra Delta, including the Padma and the Jamuna. The Ganges Delta has the shape of a triangle, and is considered to be an arcuate delta. It covers more than 105,000 km2, and although the delta lies mostly in Bangladesh and India, rivers from Bhutan, Tibet, India, approximately two-thirds of the delta is in Bangladesh. Most of the delta is composed of alluvial soils made up by small sediment particles that finally settle down as river currents slow down in the estuary, rivers carry these fine particles with them, even from their sources at glaciers as fluvio-glacial. Red and red-yellow laterite soils are found as one heads farther east, the soil has large amounts of minerals and nutrients, which is good for agriculture. It is composed of a labyrinth of channels, swamps, lakes, the Gorai-Madhumati River, one of the distributaries of the Ganges, divides the Ganges Delta into two parts, the geologically young, active, eastern delta, and the older, less active, western delta. Between 125 and 143 million people live on the delta, despite risks from floods caused by monsoons, heavy runoff from the snows of the Himalayas. A large part of the nation of Bangladesh lies in the Ganges Delta, Most of the Ganges Delta has a population density of more than 200 people per km2, making it one of the most densely populated regions in the world. Three terrestrial ecoregions cover the delta, the Lower Gangetic plains moist deciduous forests ecoregion covers most of the delta region, although the forests have mostly been cleared for agriculture and only small enclaves remain. Thick stands of grass, known as canebrakes, grow in wetter areas. These forests, too, have been almost completely converted to intensive agriculture, where the delta meets the Bay of Bengal, Sundarbans mangroves form the worlds largest mangrove ecoregion, covering an area of 20,400 square kilometres in a chain of 54 islands. They derive their name from the predominant mangrove species, Heritiera fomes, animals in the delta include the Indian python, clouded leopard, Indian elephant and crocodiles, which live in the Sundarbans. Approximately 1,020 endangered Bengal tigers are believed to inhabit the Sundarbans, the Ganges–Brahmaputra basin has tropical deciduous forests that yield valuable timber, sal, teak, and peepal trees are found in these areas. The delta region has mangrove trees and it is estimated that 30,000 chital are in the Sundarbans part of the delta
6.
Thailand
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Thailand, officially the Kingdom of Thailand, formerly known as Siam, is a country at the centre of the Indochinese peninsula in Southeast Asia. With a total area of approximately 513,000 km2, Thailand is the worlds 51st-largest country and it is the 20th-most-populous country in the world, with around 66 million people. The capital and largest city is Bangkok, Thailand is a constitutional monarchy and has switched between parliamentary democracy and military junta for decades, the latest coup being in May 2014 by the National Council for Peace and Order. Its capital and most populous city is Bangkok and its maritime boundaries include Vietnam in the Gulf of Thailand to the southeast, and Indonesia and India on the Andaman Sea to the southwest. The Thai economy is the worlds 20th largest by GDP at PPP and it became a newly industrialised country and a major exporter in the 1990s. Manufacturing, agriculture, and tourism are leading sectors of the economy and it is considered a middle power in the region and around the world. The country has always been called Mueang Thai by its citizens, by outsiders prior to 1949, it was usually known by the exonym Siam. The word Siam has been identified with the Sanskrit Śyāma, the names Shan and A-hom seem to be variants of the same word. The word Śyâma is possibly not its origin, but a learned, another theory is the name derives from Chinese, Ayutthaya emerged as a dominant centre in the late fourteenth century. The Chinese called this region Xian, which the Portuguese converted into Siam, the signature of King Mongkut reads SPPM Mongkut King of the Siamese, giving the name Siam official status until 24 June 1939 when it was changed to Thailand. Thailand was renamed Siam from 1945 to 11 May 1949, after which it reverted to Thailand. According to George Cœdès, the word Thai means free man in the Thai language, ratcha Anachak Thai means kingdom of Thailand or kingdom of Thai. Etymologically, its components are, ratcha, -ana- -chak, the Thai National Anthem, written by Luang Saranupraphan during the extremely patriotic 1930s, refers to the Thai nation as, prathet Thai. The first line of the anthem is, prathet thai ruam lueat nuea chat chuea thai, Thailand is the unity of Thai flesh. There is evidence of habitation in Thailand that has been dated at 40,000 years before the present. Similar to other regions in Southeast Asia, Thailand was heavily influenced by the culture and religions of India, Thailand in its earliest days was under the rule of the Khmer Empire, which had strong Hindu roots, and the influence among Thais remains even today. Voretzsch believes that Buddhism must have been flowing into Siam from India in the time of the Indian Emperor Ashoka of the Maurya Empire, later Thailand was influenced by the south Indian Pallava dynasty and north Indian Gupta Empire. The Menam Basin was originally populated by the Mons, and the location of Dvaravati in the 7th century, the History of the Yuan mentions an embassy from the kingdom of Sukhothai in 1282
7.
Taiwan
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Taiwan, officially the Republic of China, is a state in East Asia. Neighbours include China to the west, Japan to the northeast, Taiwan is the most populous state that is not a member of the United Nations, and the one with the largest economy. The island of Taiwan, also known as Formosa, was inhabited by Taiwanese aborigines before the 17th century. After a brief rule by the Kingdom of Tungning, the island was annexed by the Qing dynasty, the Qing ceded Taiwan to Japan in 1895 after the Sino-Japanese War. While Taiwan was under Japanese rule, the Republic of China was established on the mainland in 1912 after the fall of the Qing dynasty, following the Japanese surrender to the Allies in 1945, the ROC took control of Taiwan. However, the resumption of the Chinese Civil War led to the ROCs loss of the mainland to the Communists, and the flight of the ROC government to Taiwan in 1949. As a founding member of the United Nations, the ROC continued to represent China at the United Nations until 1971, in the early 1960s, Taiwan entered a period of rapid economic growth and industrialization, creating a stable industrial economy. In the 1980s and early 1990s, it changed from a one-party military dictatorship dominated by the Kuomintang to a multi-party democracy with universal suffrage, Taiwan is the 22nd-largest economy in the world, and its high-tech industry plays a key role in the global economy. It is ranked highly in terms of freedom of the press, health care, public education, economic freedom, the PRC has consistently claimed sovereignty over Taiwan and asserted the ROC is no longer in legitimate existence. Under its One-China Policy the PRC refused diplomatic relations with any country that recognizes the ROC, the PRC has threatened the use of military force in response to any formal declaration of independence by Taiwan or if PRC leaders decide that peaceful unification is no longer possible. There are various names for the island of Taiwan in use today, the former name Formosa dates from 1542, when Portuguese sailors sighted the main island of Taiwan and named it Ilha Formosa, which means beautiful island. The name Formosa eventually replaced all others in European literature and was in use in English in the early 20th century. This name was adopted into the Chinese vernacular as the name of the sandbar. The modern word Taiwan is derived from this usage, which is seen in forms in Chinese historical records. Use of the current Chinese name was formalized as early as 1684 with the establishment of Taiwan Prefecture, through its rapid development, the entire Formosan mainland eventually became known as Taiwan. The official name of the state is the Republic of China and it was a member of the United Nations representing China until 1971, when it lost its seat to the Peoples Republic of China. Over subsequent decades, the Republic of China has become known as Taiwan. In some contexts, especially ones from the ROC government
8.
China
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China, officially the Peoples Republic of China, is a unitary sovereign state in East Asia and the worlds most populous country, with a population of over 1.381 billion. The state is governed by the Communist Party of China and its capital is Beijing, the countrys major urban areas include Shanghai, Guangzhou, Beijing, Chongqing, Shenzhen, Tianjin and Hong Kong. China is a power and a major regional power within Asia. Chinas landscape is vast and diverse, ranging from forest steppes, the Himalaya, Karakoram, Pamir and Tian Shan mountain ranges separate China from much of South and Central Asia. The Yangtze and Yellow Rivers, the third and sixth longest in the world, respectively, Chinas coastline along the Pacific Ocean is 14,500 kilometers long and is bounded by the Bohai, Yellow, East China and South China seas. China emerged as one of the worlds earliest civilizations in the basin of the Yellow River in the North China Plain. For millennia, Chinas political system was based on hereditary monarchies known as dynasties, in 1912, the Republic of China replaced the last dynasty and ruled the Chinese mainland until 1949, when it was defeated by the communist Peoples Liberation Army in the Chinese Civil War. The Communist Party established the Peoples Republic of China in Beijing on 1 October 1949, both the ROC and PRC continue to claim to be the legitimate government of all China, though the latter has more recognition in the world and controls more territory. China had the largest economy in the world for much of the last two years, during which it has seen cycles of prosperity and decline. Since the introduction of reforms in 1978, China has become one of the worlds fastest-growing major economies. As of 2016, it is the worlds second-largest economy by nominal GDP, China is also the worlds largest exporter and second-largest importer of goods. China is a nuclear weapons state and has the worlds largest standing army. The PRC is a member of the United Nations, as it replaced the ROC as a permanent member of the U. N. Security Council in 1971. China is also a member of numerous formal and informal multilateral organizations, including the WTO, APEC, BRICS, the Shanghai Cooperation Organization, the BCIM, the English name China is first attested in Richard Edens 1555 translation of the 1516 journal of the Portuguese explorer Duarte Barbosa. The demonym, that is, the name for the people, Portuguese China is thought to derive from Persian Chīn, and perhaps ultimately from Sanskrit Cīna. Cīna was first used in early Hindu scripture, including the Mahābhārata, there are, however, other suggestions for the derivation of China. The official name of the state is the Peoples Republic of China. The shorter form is China Zhōngguó, from zhōng and guó and it was then applied to the area around Luoyi during the Eastern Zhou and then to Chinas Central Plain before being used as an occasional synonym for the state under the Qing
9.
Arsenous acid
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Arsenous acid is the inorganic compound with the formula H3AsO3. It is known to occur in solutions, but it has not been isolated as a pure material. As3 is a molecule consisting of three hydroxyl groups bonded to arsenic. The 1H NMR spectrum of arsenous acid solutions consists of a single signal consistent with the high symmetry. In contrast, the nominally related phosphorus species H3PO3 mainly adopts the structure HPO2, the differing behaviors of the As and P compounds reflect a trend whereby high oxidation states are more stable for lighter members of main group elements than their heavier congeners. The preparation of As3 involves a slow hydrolysis of arsenic trioxide in water, addition of base converts arsenous acid to the arsenite ions −, 2−, and 3−. The first pKa is 9.2, As3 is a weak acid, reactions attributed to aqueous arsenic trioxide are due to arsenous acid and its conjugate bases. Arsenic-containing compounds are toxic and carcinogenic. The anhydride form of acid, arsenic trioxide, is used as a herbicide, pesticide. Case Studies in Environmental Medicine - Arsenic Toxicity
10.
Arsenic acid
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Arsenic acid is the chemical compound with the formula H3AsO4. More descriptively written as AsO3, this acid is the arsenic analogue of phosphoric acid. Arsenate and phosphate salts behave very similarly, arsenic acid as such has not been isolated, but only found in solution where it is largely ionized. Its hemihydrate form does form stable crystals, crystalline samples dehydrate with condensation at 100 °C. It is a species of idealized symmetry C3v with As–O bonds lengths ranging from 1.66 to 1.71 Å. The highly basic arsenate ion is the product of the third ionization, unlike phosphoric acid, arsenic acid is an oxidizer, illustrated by its ability to convert iodide to iodine. Arsenic acid is prepared by treating arsenic trioxide with concentrated nitric acid, arsenic acid is slowly formed when arsenic pentoxide is dissolved in water, and when meta- or pyroarsenic acid is treated with cold water. Arsenic acid can also be prepared directly from elemental arsenic by moistening it,2 As +3 H2O +5 O3 →2 H3AsO4 +5 O2 Commercial applications of arsenic acid are limited by its toxicity. It has found use as a wood preservative, broad-spectrum biocide, a finishing agent for glass and metal. The LD50 in rabbits is 6 mg/kg
11.
Chile
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Chile, officially the Republic of Chile, is a South American country occupying a long, narrow strip of land between the Andes to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, Chilean territory includes the Pacific islands of Juan Fernández, Salas y Gómez, Desventuradas, and Easter Island in Oceania. Chile also claims about 1,250,000 square kilometres of Antarctica, the arid Atacama Desert in northern Chile contains great mineral wealth, principally copper. Southern Chile is rich in forests and grazing lands, and features a string of volcanoes and lakes, the southern coast is a labyrinth of fjords, inlets, canals, twisting peninsulas, and islands. Spain conquered and colonized Chile in the century, replacing Inca rule in northern and central Chile. After declaring its independence from Spain in 1818, Chile emerged in the 1830s as a relatively stable authoritarian republic, in the 1960s and 1970s the country experienced severe left-right political polarization and turmoil. The regime, headed by Augusto Pinochet, ended in 1990 after it lost a referendum in 1988 and was succeeded by a coalition which ruled through four presidencies until 2010. Chile is today one of South Americas most stable and prosperous nations and it leads Latin American nations in rankings of human development, competitiveness, income per capita, globalization, state of peace, economic freedom, and low perception of corruption. It also ranks high regionally in sustainability of the state, Chile is a founding member of the United Nations, the Union of South American Nations and the Community of Latin American and Caribbean States. There are various theories about the origin of the word Chile, another theory points to the similarity of the valley of the Aconcagua with that of the Casma Valley in Peru, where there was a town and valley named Chili. Another origin attributed to chilli is the onomatopoeic cheele-cheele—the Mapuche imitation of the warble of a locally known as trile. The Spanish conquistadors heard about this name from the Incas, ultimately, Almagro is credited with the universalization of the name Chile, after naming the Mapocho valley as such. The older spelling Chili was in use in English until at least 1900 before switching over to Chile, stone tool evidence indicates humans sporadically frequented the Monte Verde valley area as long as 18,500 years ago. About 10,000 years ago, migrating Native Americans settled in fertile valleys, settlement sites from very early human habitation include Monte Verde, Cueva del Milodon and the Pali Aike Craters lava tube. They fought against the Sapa Inca Tupac Yupanqui and his army, the result of the bloody three-day confrontation known as the Battle of the Maule was that the Inca conquest of the territories of Chile ended at the Maule river. The next Europeans to reach Chile were Diego de Almagro and his band of Spanish conquistadors, the Spanish encountered various cultures that supported themselves principally through slash-and-burn agriculture and hunting. The conquest of Chile began in earnest in 1540 and was carried out by Pedro de Valdivia, one of Francisco Pizarros lieutenants, who founded the city of Santiago on 12 February 1541. Although the Spanish did not find the gold and silver they sought, they recognized the agricultural potential of Chiles central valley
12.
Tube well
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A tube well is a type of water well in which a long 100–200 millimetres wide stainless steel tube or pipe is bored into an underground aquifer. The lower end is fitted with a strainer, and a pump water for irrigation. The required depth of the well depends on the depth of the water table, a small reservoir of water is made at the outlet of the tube well. This reservoir is used for different usage of water by the local population, in the past, the pump was typically driven by a large diesel engine. Today electric motors are commonly used on account of economy. The tube well casing houses the inlet, cylinder, piston valves, casing to support the external surfaces of the borehole against collapse may be needed, either temporarily or permanently, and is often made of PVC pipe, which is both cheap and inert. Seepage down the well bore is prevented by the sanitary seal. Seepage from the ground above the aquifer is excluded by the lengths of plain casing, water to be pumped is admitted through slots in the lower lengths of casing. Water abstracted from aquifers in relatively soft ground usually contains sand or silt particles, methods of preventing these particles from reaching the pump are of two general types, screening and sand/gravel packing. The drawing shows slots in the PVC casing which can be cut on site, using a hacksaw and it is sealed The drawing shows graded sand and gravel, which is placed from the top of the borehole. More compact, pre-bonded, packs of sand and/or gravel are available commercially, high concentrations of arsenic occur naturally in the soil in some areas of Bangladesh. The water table is close to the surface. Able to irrigate a larger area. More reliable during periods of drought when water dries up
13.
Bihar
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Bihar is a state in the eastern part of India. It is the 13th-largest state of India, with an area of 94,163 km2. The third-largest state of India by population, it is contiguous with Uttar Pradesh to its west, Nepal to the north, the Bihar plain is split by the river Ganges which flows from west to east. On November 15,2000, southern Bihar was ceded to form the new state of Jharkhand, only 11. 3% of the population of Bihar lives in urban areas, which is lowest in India after Himachal Pradesh. Additionally, almost 58% of Biharis are below the age of 25, the official languages of the state are Hindi and Urdu. Other languages commonly used within the state include Bhojpuri, Maithili, Magahi, Bajjika, in ancient and classical India, Bihar was considered a centre of power, learning, and culture. From Magadha arose Indias first empire, the Maurya empire, as well as one of the worlds most widely adhered-to religions, Magadha empires, notably under the Maurya and Gupta dynasties, unified large parts of South Asia under a central rule. Another region of Bihar is Mithila which was a centre of Brahmanical learning. Since the late 1970s, Bihar has lagged far behind other Indian states in terms of social, the state government has, however, made significant strides in developing the state. The name Bihar is derived from the Sanskrit and Pali word, Vihara, the region roughly encompassing the present state was dotted with Buddhist vihara, the abodes of Buddhist monks in the ancient and medieval periods. Medieval writer Minhaj al-Siraj Juzjani records in the Tabakat-i-Nasiri that in 1198, Bakhtiyar Khalji committed a massacre in a town now known as Bihar Sharif, chirand, on the northern bank of the Ganga River, in Saran district, has an archaeological record from the Neolithic age. Regions of Bihar—such as Magadha, Mithila and Anga—are mentioned in religious texts, the power centre of ancient Bihar was in the region of modern-day southwestern Bihar called Magadha, which remained the centre of power, learning, and culture in India for 1000 years. The Haryanka dynasty, founded in 684 BC, ruled Magadha from the city of Rajgriha, the two well-known kings from this dynasty were Bimbisara and his son Ajatashatru, who imprisoned his father to ascend the throne. Ajatashatru founded the city of Pataliputra which later became the capital of Magadha and he declared war and conquered the Vajji of north Bihar, another powerful Mahajanapada north of Ganges with its capital at Vaishali. Vaishali was ruled by the Licchavi clan, who had a form of government where the king was elected from the number of rajas. The Haryanka dynasty was followed by the Shishunaga dynasty, later the Nanda Dynasty ruled a vast tract stretching from Bengal to Punjab. The Nanda dynasty was replaced by the Maurya Empire, Indias first empire, the Maurya Empire and the religion of Buddhism arose in the region that now makes up modern Bihar. The Mauryan Empire, which originated from Magadha in 325 BC, was founded by Chandragupta Maurya and it had its capital at Pataliputra
14.
Parts-per notation
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In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e. g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement, commonly used are ppm, ppb, ppt and ppq. Parts-per notation is often used describing dilute solutions in chemistry, for instance, the unit “1 ppm” can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution. When working with aqueous solutions, it is common to assume that the density of water is 1.00 g/mL, therefore, it is common to equate 1 kilogram of water with 1 L of water. Consequently,1 ppm corresponds to 1 mg/L and 1 ppb corresponds to 1 μg/L, similarly, parts-per notation is used also in physics and engineering to express the value of various proportional phenomena. For instance, a metal alloy might expand 1.2 micrometers per meter of length for every degree Celsius. For instance, the accuracy of distance measurements when using a laser rangefinder might be 1 millimeter per kilometer of distance, this could be expressed as “Accuracy =1 ppm. ”Parts-per notations are all dimensionless quantities, in mathematical expressions. In fractions like “2 nanometers per meter” so the quotients are pure-number coefficients with positive values less than 1, when parts-per notations, including the percent symbol, are used in regular prose, they are still pure-number dimensionless quantities. However, they take the literal “parts per” meaning of a comparative ratio. Parts-per notations may be expressed in terms of any unit of the same measure, in nuclear magnetic resonance spectroscopy, chemical shift is usually expressed in ppm. It represents the difference of a frequency in parts per million from the reference frequency. The reference frequency depends on the magnetic field and the element being measured. It is usually expressed in MHz, typical chemical shifts are rarely more than a few hundred Hz from the reference frequency, so chemical shifts are conveniently expressed in ppm. Parts-per notation gives a quantity that does not depend on the instruments field strength. One part per hundred is generally represented by the percent symbol and denotes one part per 100 parts, one part in 102, and this is equivalent to approximately one drop of water diluted into 5 milliliters or about fifteen minutes out of one day. One part per thousand should generally be spelled out in full and it may also be denoted by the millage symbol. Note however, that specific disciplines such as oceanography, as well as educational exercises, one part per thousand denotes one part per 1000 parts, one part in 103, and a value of 1 × 10−3. This is equivalent to one drop of water diluted into 50 milliliters or about one, one part per ten thousand is denoted by the permyriad symbol
15.
Bill Clinton
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William Jefferson Clinton is an American politician who served as the 42nd President of the United States from 1993 to 2001. Prior to the Presidency he was the 40th Governor of Arkansas from 1979 to 1981, before that, he served as Arkansas Attorney General from 1977 to 1979. A member of the Democratic Party, Clinton was ideogically a New Democrat, Clinton is married to Hillary Clinton, who served as United States Secretary of State from 2009 to 2013 and U. S. Senator from New York from 2001 to 2009, and served the Democratic nominee for President in 2016, Bill Clinton and Hillary Rodham both earned degrees from Yale Law School, where they met and began dating. As Governor of Arkansas, Clinton overhauled the states education system, Clinton was elected President of the United States in 1992, defeating incumbent George H. W. Bush. At age 46, he was the third-youngest president and the first from the Baby Boomer generation, Clinton presided over the longest period of peacetime economic expansion in American history and signed into law the North American Free Trade Agreement. After failing to pass health care reform, the Democratic House was ousted when the Republican Party won control of the Congress in 1994. Two years later, in 1996, Clinton became the first Democrat since Franklin D. Roosevelt to be elected to a second term, Clinton passed welfare reform and the State Childrens Health Insurance Program, providing health coverage for millions of children. Clinton was acquitted by the U. S. Senate in 1999, the Congressional Budget Office reported a budget surplus between the years 1998 and 2000, the last three years of Clintons presidency. In foreign policy, Clinton ordered U. S. Clinton left office with the highest end-of-office approval rating of any U. S. President since World War II, since then, Clinton has been involved in public speaking and humanitarian work. He created the William J. Clinton Foundation to address international causes, such as the prevention of AIDS, in 2004, Clinton published his autobiography, My Life. In 2009, Clinton was named the United Nations Special Envoy to Haiti, since leaving office, Clinton has been rated highly in public opinion polls of U. S. Presidents. Clinton was born on August 19,1946, at Julia Chester Hospital in Hope, Arkansas and he was the son of William Jefferson Blythe Jr. a traveling salesman who had died in an automobile accident three months before his birth, and Virginia Dell Cassidy. His parents had married on September 4,1943, but this later proved to be bigamous. Soon after their son was born, his mother traveled to New Orleans to study nursing, leaving her son in Hope with her parents Eldridge and Edith Cassidy, who owned and ran a small grocery store. At a time when the Southern United States was segregated racially, in 1950, Bills mother returned from nursing school and married Roger Clinton Sr. who owned an automobile dealership in Hot Springs, Arkansas, with his brother and Earl T. Ricks. The family moved to Hot Springs in 1950, although he immediately assumed use of his stepfathers surname, it was not until Clinton turned fifteen that he formally adopted the surname Clinton as a gesture toward his stepfather. In Hot Springs, Clinton attended St. Johns Catholic Elementary School, Ramble Elementary School, and Hot Springs High School—where he was a student leader, avid reader
16.
George W. Bush
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George Walker Bush is an American politician who served as the 43rd President of the United States from 2001 to 2009. He was also the 46th Governor of Texas from 1995 to 2000 and he is the eldest son of Barbara and George H. W. Bush. After graduating from Yale University in 1968 and Harvard Business School in 1975, Bush married Laura Welch in 1977 and ran unsuccessfully for the House of Representatives shortly thereafter. He later co-owned the Texas Rangers baseball team before defeating Ann Richards in the 1994 Texas gubernatorial election and he is the second president to assume the nations highest office after his father, following the lead of John Quincy Adams. He is also a brother of Jeb Bush, a former Governor of Florida who was a candidate for the Republican presidential nomination in the 2016 presidential election, the September 11 terrorist attacks occurred eight months into Bushs first term as president. Bush responded with what became known as the Bush Doctrine, launching a War on Terror, a military campaign that included the war in Afghanistan in 2001. He also promoted policies on the economy, health care, education, Social Security reform and his tenure included national debates on immigration, Social Security, electronic surveillance, and torture. In the 2004 Presidential race, Bush defeated Democratic Senator John Kerry in another close election. After his re-election, Bush received increasingly heated criticism from across the spectrum for his handling of the Iraq War, Hurricane Katrina. Amid this criticism, the Democratic Party regained control of Congress in the 2006 elections, Bush left office in 2009, returning to Texas where he purchased a home in Crawford. He wrote a memoir, Decision Points and his presidential library was opened in 2013. His presidency has been ranked among the worst in historians polls published in the late 2000s and 2010s. George Walker Bush was born on July 6,1946, at Grace-New Haven Hospital in New Haven, Connecticut, as the first child of George Herbert Walker Bush and his wife, the former Barbara Pierce. He was raised in Midland and Houston, Texas, with four siblings, Jeb, Neil, Marvin, another younger sister, Robin, died from leukemia at the age of three in 1953. His grandfather, Prescott Bush, was a U. S and his father, George H. W. Bush, was Ronald Reagans Vice President from 1981 to 1989 and the 41st U. S. President from 1989 to 1993. Bush has English and some German ancestry, along with more distant Dutch, Welsh, Irish, French, Bush attended public schools in Midland, Texas, until the family moved to Houston after he had completed seventh grade. He then spent two years at The Kinkaid School, a school in Houston. Bush attended high school at Phillips Academy, a school in Andover, Massachusetts
17.
Midnight regulations
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Midnight regulations are United States federal government regulations created by executive branch agencies in the lame duck period of an outgoing presidents administration. The United States Congress passes laws that sometimes outline only broad policy mandates, rulemaking by the specialist agencies in the executive branch adds necessary detail to these laws. Rulemaking also provides an administration with an opportunity to exert influence over government without having to go through Congress to change the law. U. S. federal law mandates a 60-day waiting period before any major regulatory changes become law, thus, some presidents try to publish new major regulations on November 21,60 days before the new presidents inauguration on January 20. Minor regulations, or those that have less than US$100 million in effect on the economy or do not have major social significance, have a similar 30-day waiting period. Tom Firey, of the Cato Institutes Regulation magazine, argues that most midnight regulations are in fact primarily political symbolism rather than major regulatory change, regulations that have not yet become law can be placed on hold by the incoming President. Regulations that take effect before a new president takes office can still be reversed by the executive agencies. In addition, reversing recently enacted regulations may distract an incoming administration from its own regulatory agenda, but in each case the period in which the disfavored regulations are law may permit undesired results to take place. For example, a power plant could be built in the period that a federal regulation is law. A third option is for Congress to overturn the regulation under the Congressional Review Act of 1996, of the 50,000 regulations enacted since the Act was passed, only one has been so overturned. The term midnight regulation entered the lexicon in 1980–81, during the months of Jimmy Carters single term as president. Carters administration set a new record for midnight regulations by publishing more than 10,000 pages of new rules between Election Day and Ronald Reagans Inauguration Day, the term is an allusion to the midnight judges appointed by John Adams in the final months of his presidency. The Clinton Administration enacted a flurry of rules limiting logging and lead paint, raising energy efficiency. One of Clintons midnight regulations imposed a more stringent drinking water standard for arsenic after years of EPA study, although Bush suspended the new regulation upon taking office, EPA head Christine Todd Whitman eventually approved it. The Bush administration also approved thousands of pages of dozens of new agency rules, many of these regulations were promulgated in the hope of ensuring enactment before Barack Obama took office and could prevent the rules from becoming law. Bush Chief of Staff Joshua Bolten encouraged timely passage of the rules in a May 2008 memo to agencies suggesting that final versions be submitted by November 1, a subcommittee on administrative law in the Democratic House of Representatives held a hearing on midnight regulations the month after Obamas inauguration. The Obama Administration recognized the potential for midnight regulations as early as the end of 2015. ”In the Obama Administration’s final Unified Agenda, starting in November 2016, OIRA concluded review of 57 rule-makings – a 26 percent increase over the monthly pace from the rest of 2016. Fourteen of these measures were “economically significant” rule-makings and that represents the second-highest total in any November “midnight period” since at least 1996
18.
Christine Todd Whitman
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She was New Jerseys first and, to date, only female governor. She was the woman and first Republican woman to defeat an incumbent governor in a general election in the United States. She was also the first Republican woman to be reelected governor, Whitman was born Christine Todd in New York City, and grew up in Hunterdon County, New Jersey, the daughter of Eleanor Prentice Todd and businessman Webster B. Todd, both interested in New Jersey Republican politics and she attended Far Hills Country Day School and the Chapin School in Manhattan. After graduating from Wheaton College in 1968, earning a bachelor of degree in government. Whitman is a descendant of two New Jersey political families, the Todds and the Schleys, and is related by marriage to New Yorks politically prestigious Whitman family. Her husband, who died in July 2015, was private equity investor John R. Whitman and her maternal grandfather, Reeve Schley, was a member of Wolfs Head Society at Yale and the vice president of Chase Bank. He was also a president of the Russian-American Chamber of Commerce. With her late husband, Whitman has two children and her daughter Kate has followed her mother into politics. She also was a Congressional aide and in 2007, she was named director of the Republican Leadership Council. Whitman also had a Scottish Terrier named Coors, who is the mother of former president George W. Bushs dog Barney, Whitman has been a resident of Tewksbury Township, New Jersey. During the Nixon administration, Whitman worked for the Office of Economic Opportunity under Donald Rumsfeld and she was appointed to the board of trustees of Somerset County College, now Raritan Valley Community College. Elected to two terms on the Somerset County Board of Chosen Freeholders, she served as deputy director and director of the board, among her accomplishments was construction of a new county courthouse. From 1988 to 1990, she served as president of the New Jersey Board of Public Utilities under governor Thomas Kean, in 1990, Whitman ran for the U. S. Senate against incumbent Bill Bradley, and lost in a close election. She was considered as an underdog against the popular Bradley, during her campaign, Whitman criticized the income tax hike proposed by then governor James Florio. Bradley did not take a stance on the issue, in 1993, Whitman helped to found the Committee for Responsible Government, an advocacy group espousing moderate positions in the Republican Party. In 1997, the CRG softened its position, and renamed itself as the Republican Leadership Council. Whitman ran against incumbent James Florio for governor in 1993, and she was the second woman and first Republican woman to defeat an incumbent governor in a general election, but was unable to gain a majority of the votes, winning by a plurality
19.
New Jersey
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New Jersey is a state in the Northeastern and mid-Atlantic regions of the United States. It is bordered on the north and east by New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania, New Jersey is the fourth-smallest state but the 11th-most populous and the most densely populated of the 50 United States. New Jersey lies entirely within the statistical areas of New York City. New Jersey was inhabited by Native Americans for more than 2,800 years, in the early 17th century, the Dutch and the Swedes made the first European settlements. New Jersey was the site of decisive battles during the American Revolutionary War in the 18th century. In the 19th century, factories in cities such as Camden, Paterson, Newark, Trenton, around 180 million years ago, during the Jurassic Period, New Jersey bordered North Africa. The pressure of the collision between North America and Africa gave rise to the Appalachian Mountains, around 18,000 years ago, the Ice Age resulted in glaciers that reached New Jersey. As the glaciers retreated, they left behind Lake Passaic, as well as rivers, swamps. New Jersey was originally settled by Native Americans, with the Lenni-Lenape being dominant at the time of contact, scheyichbi is the Lenape name for the land that is now New Jersey. The Lenape society was divided into clans that were based upon common female ancestors. These clans were organized into three distinct phratries identified by their animal sign, Turtle, Turkey, and Wolf and they first encountered the Dutch in the early 17th century, and their primary relationship with the Europeans was through fur trade. The Dutch became the first Europeans to lay claim to lands in New Jersey, the Dutch colony of New Netherland consisted of parts of modern Middle Atlantic states. Although the European principle of ownership was not recognized by the Lenape. The first to do so was Michiel Pauw who established a patronship called Pavonia in 1630 along the North River which eventually became the Bergen, peter Minuits purchase of lands along the Delaware River established the colony of New Sweden. During the English Civil War, the Channel Island of Jersey remained loyal to the British Crown and it was from the Royal Square in St. Helier that Charles II of England was proclaimed King in 1649, following the execution of his father, Charles I. The North American lands were divided by Charles II, who gave his brother, the Duke of York, the region between New England and Maryland as a proprietary colony. James then granted the land between the Hudson River and the Delaware River to two friends who had remained loyal through the English Civil War, Sir George Carteret and Lord Berkeley of Stratton, the area was named the Province of New Jersey. Since the states inception, New Jersey has been characterized by ethnic, New England Congregationalists settled alongside Scots Presbyterians and Dutch Reformed migrants
20.
Fallon, Nevada
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Fallon is a city in Churchill County, Nevada, United States. The population was 8,606 at time of the 2010 census, Fallon is the county seat of Churchill County and is located in the Lahontan Valley. Fallon and Churchill County are mostly agricultural areas, although the area is arid, approximately 50,000 acres of its pastureland are irrigated with water from the Truckee–Carson Irrigation District. The principal crop grown is alfalfa for livestock feed, the Heart O Gold cantaloupes of Churchill County were once distributed across the United States, but are now grown mostly for consumption in Nevada. U. S. Highway 50 and US95 intersect in Fallon and it is one of the towns on the so-called Loneliest Highway in America, the stretch of US50 across most of Nevada that is known for its remoteness. Eastbound travelers from Fallon must drive 110 miles to find the next town, the town and post office were established July 24,1896 in a little shack of Michael Fallon. Fallon is located in western Churchill County at the geographic coordinates 39°28′22″N 118°46′44″W and it is in the Lahontan Valley, a former lakebed into which flows the Carson River, which passes north of the city. According to the United States Census Bureau, Fallon has an area of 3.65 square miles, of which 3.63 square miles is land and 0.02 square miles. Fallon experiences a desert climate, with hot summers and cold winters. Due to Fallons altitude and aridity, the Diurnal temperature variation is quite substantial, Fallons climate is quite dry, due to its location in the rain shadow of the Sierra Nevada. Summer days can be hot, but temperatures are cooler than in such as the Mojave, Sonoran. In the winter, daytime temperatures are usually above freezing, Fallon can experience heavy fog in winter, known as pogonip. As of the census of 2000, there were 7,536 people,3,004 households, the population density was 2,474.1 people per square mile. There were 3,336 housing units at a density of 1,095.2 per square mile. The racial makeup of the city was 76. 50% White,2. 00% African American,3. 00% Native American,4. 70% Asian,0. 3% Pacific Islander,0. 3% from other races, and 3. 3% from two or more races. Hispanic or Latino of any race were 9. 9% of the population,30. 7% of all households were made up of individuals and 11. 4% had someone living alone who was 65 years of age or older. The average household size was 2.45 and the family size was 3.06. In the city, the population was out with 28. 4% under the age of 18,10. 3% from 18 to 24,29. 7% from 25 to 44,19. 4% from 45 to 64
21.
Verde River
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The Verde River is a major tributary of the Salt River in the U. S. state of Arizona. It is about 170 miles long and carries a mean flow of 602 cubic feet per second at its mouth and it is one of the largest perennial streams in Arizona. The river begins below the dam at Sullivan Lake, fed by Big Chino Wash, the cities of Camp Verde, Clarkdale and Cottonwood are the main population centers along the river. The Verde River and the Salt River meet near Fountain Hills, the Salt River flows into the Gila River west of Phoenix. In 1984, the United States Congress designated 40.5 miles of the Verde River as Wild and Scenic through the National Wild, the Scenic portion begins at Beasley Flats and extends downstream about 19 miles to the northern boundary of the Mazatzal Wilderness. The Wild portion extends from there to the mouth of Red Creek, in 1986, a 6-mile stretch of the river was identified by the state of Arizona as a critical natural resource. This reach of the Verde River and its riparian zone. The park, called the Verde River Greenway State Natural Area, dead Horse Ranch State Park, near Cottonwood, is adjacent to the Greenway. Plants found in riparian zones along the river include Arizona alder, sycamore, and walnut trees, a variety of willows, reeds, cattails, box elder, and saltcedar, among others. Aquatic vertebrates along the Verde River include North American beaver, belted kingfishers, great blue herons, otters, Chiricahua leopard frogs, Sonoran mud turtles, and others. Among the 27 species of fish found in the river are carp, flathead catfish, roundtail chub, Gila chub, bass, desert sucker, mosquitofish, red shiner, and Sonora sucker. Beaver were trapped with considerable success on the Verde River by fur trappers led by Ewing Young, edgar Alexander Mearns wrote in his 1907 naturalist survey Mammals of the Mexican Boundary of the United States that beaver were present on nearly all streams of the Colorado Basin. Re-introductions of beaver in recent times have transformed even small desert streams into robust riparian habitat, increasing species abundance, floating the Verde River in rafts and kayaks is a popular pastime as it runs through scenic valleys and the Mazatzal Wilderness. The facilities described below are maintained by the Tonto National Forest authority, kayak rentals, shuttles, boating gear and services are available in Clarkdale, Cottonwood and Camp Verde. Several commercial outfitters offer guided trips on the Verde River, the Verde River above Camp Verde has about 70 miles of fishable waters at an average elevation of 3,800 feet above sea level. The nearest town with fuel, restaurants, lodging, groceries, Fish species frequenting this stretch of the river include largemouth bass, smallmouth bass, sunfish, channel catfish, flathead catfish, yellow perch, chub, carp, and, in winter, rainbow trout. Crayfish and bullfrogs are also found, from Camp Verde to Horseshoe Lake, about 60 miles of fishable waters are at an average elevation of 2,800 feet. The nearest town with fuel and other supplies and amenities is Camp Verde, species along this stretch include largemouth and smallmouth bass, sunfish, channel and flathead catfish, carp, crayfish, and bullfrogs
22.
Arizona
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Arizona is a state in the southwestern region of the United States. It is also part of the Western United States and the Mountain West states and it is the sixth largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix, Arizona is one of the Four Corners states. It has borders with New Mexico, Utah, Nevada, California, and Mexico, Arizonas border with Mexico is 389 miles long, on the northern border of the Mexican states of Sonora and Baja California. Arizona is the 48th state and last of the states to be admitted to the Union. Historically part of the territory of Alta California in New Spain, after being defeated in the Mexican–American War, Mexico ceded much of this territory to the United States in 1848. The southernmost portion of the state was acquired in 1853 through the Gadsden Purchase, Southern Arizona is known for its desert climate, with very hot summers and mild winters. There are ski resorts in the areas of Flagstaff, Alpine, in addition to the Grand Canyon National Park, there are several national forests, national parks, and national monuments. To the European settlers, their pronunciation sounded like Arissona, the area is still known as alĭ ṣonak in the Oodham language. Another possible origin is the Basque phrase haritz ona, as there were numerous Basque sheepherders in the area, There is a misconception that the states name originated from the Spanish term Árida Zona. See also lists of counties, islands, rivers, lakes, state parks, national parks, Arizona is in the Southwestern United States as one of the Four Corners states. Arizona is the sixth largest state by area, ranked after New Mexico, of the states 113,998 square miles, approximately 15% is privately owned. The remaining area is public forest and park land, state trust land, Arizona is well known for its desert Basin and Range region in the states southern portions, which is rich in a landscape of xerophyte plants such as the cactus. This regions topography was shaped by volcanism, followed by the cooling-off. Its climate has hot summers and mild winters. The state is well known for its pine-covered north-central portion of the high country of the Colorado Plateau. Like other states of the Southwest United States, Arizona has an abundance of mountains, despite the states aridity, 27% of Arizona is forest, a percentage comparable to modern-day France or Germany. The worlds largest stand of pine trees is in Arizona
23.
Terai
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The Terai is a lowland region in southern Nepal and northwestern India that lies south of the outer foothills of the Himalayas, the Siwalik Hills, and north of the Indo-Gangetic Plain. This lowland belt is characterised by tall grasslands, scrub savannah, sal forests, in northern India, the Terai spreads from the Yamuna River eastward across Himachal Pradesh, Haryana, Uttarakhand, Uttar Pradesh and Bihar. The Terai is part the Terai-Duar savanna and grasslands ecoregion, the corresponding lowland region in West Bengal, Bangladesh, Bhutan and Assam in the Brahmaputra River basin is called Dooars. In Nepal, the Terai lies at an altitude of between 67 and 300 m and comprises more than 50 wetlands, north of the Terai rises the Bhabhar, a narrow but continuous belt of forest about 8–12 km wide. In Hindi the region is called तराई, tarāī meaning foot-hill, in Nepali, the region is called तराइ tarāi meaning the low-lying land, plain and especially the low-lying land at the foot of the Himālayas. The regions name in Urdu is ترائي tarāʼī meaning lands lying at the foot of a watershed or on the banks of a river, low ground flooded with water, valley, basin, marshy ground, marsh, swamp, meadow. Medium rivers such as the Rapti rise in the Mahabharat Range, the geological structure of the region consists of old and new alluvium, both of which constitute alluvial deposits of mainly sand, clay, silt, gravels and coarse fragments. The new alluvium is renewed every year by fresh deposits brought down by active streams, old alluvium is found rather away from river courses, especially on uplands of the plain where silting is a rare phenomenon. A large number of small and usually seasonal rivers flow through the Terai, the soil in the Terai is alluvial and fine to medium textured. Forest cover in the Terai and hill areas has decreased at a rate of 1. 3% between 1978 and 1979, and 2. 3% between 1990 and 1991. With deforestation and cultivation increasing, a mixture of gravel, boulders and sand evolves. The reduction in slope as rivers exit the hills and then transition from the sloping Bhabhar to the nearly level Terai causes current to slow and this deposition process creates multiple channels with shallow beds, enabling massive floods as monsoon-swollen rivers overflow their low banks and shift channels. Many areas show erosion such as gullies, there are several differences between the climate on the western edge of the Terai at Chandigarh in India and at Biratnagar in Nepal near the eastern edge. Moving inland and away from sources in the Bay of Bengal. In the far western Terai, which is five degrees latitude further north, total rainfall markedly diminishes from east to west. The monsoon arrives later, is less intense and ends sooner. However, winters are wetter in the west, in India, the Terai extends over the states of Himachal Pradesh, Haryana, Uttarakhand, Uttar Pradesh and Bihar. The Inner Terai refers to the valleys in the lowlands of southern Nepal located between the Mahabharat and Shivalik ranges
24.
Nawalparasi District
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Nawalparasi District (Nepali, ne, नवलपरासी जिल्ला, Listen, part of which belongs to Province No.4 and part to Province No. 5, is one of the districts of Nepal, a landlocked country of South Asia. The district, with Ramgram as its headquarters, covers an area of 2,162 square kilometres and has a population of 643,508. This district has given birth to many Nepals top-level people, including the late Prime Minister Tanka Prasad Acharya, the midpoint of Nepals east–west highway Mahendra Highway lies in this district. The big industries such as Chaudhary Udhyog Gram, Bhrikuti pulp, since Parasi is the headquarter of Nawalparasi district many of the clerical offices are located there. Nepals one of the biggest Sugar factory, Lumbini Sugar Industry, developing cities such as Devchuli Municipality, Gaindakot Municipality, Kawasoti Municipality Sunwal Municipality, Madhyabindu Municipality and Bardaghat Municipality are located here. Famous towns in Nawalpur Ragion are Gaidakot, Rajahar, Keurani, Pragatinagar, Kawasoti, aidnagar Danda, Chormara, half of the Nawalpur Region is mainly hilly areas mainly populated by Brahmins, Magar and Chhetri people and terai area is mainly populated by Tharu people. Nawalparasi district is connected to Rupandehi District on the west, Palpa and Tanahun Districts on the north, Chitwan District on the east and south, the longest road of Mahendra highway,99 km in length, lies in this district
25.
Kathmandu Valley
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The Kathmandu Valley, located in Nepal, lies at the crossroads of ancient civilizations of Asia, and has at least 130 important monuments, including several pilgrimage sites for Hindus and Buddhists. There are seven World Heritage Sites within the valley, historically, the valley and adjoining areas made up a confederation known as the Nepal Mandala. Until the 15th century, Bhaktapur was its capital, when two other capitals, Kathmandu and Lalitpur, were established. After the annexation of the valley by the Gorkha Kingdom, and subsequent conversion of the valley as the capital of their empire, the Kathmandu Valley is the most developed and populated place in Nepal. The majority of offices and headquarters are located in the valley and it is popular with tourists for its unique architecture, and rich culture that includes the highest number of jatras in Nepal. The valley itself was referred to as Nepal Proper by British historians, thousands of people died and tens of thousands of buildings and structures collapsed in Kathmandu Valley in the April 2015 Nepal earthquake. The city of Kathmandu is named after a structure in Durbar Square called by the Sanskrit name Kāsṣtha mandapa Wooden shelter and it was destroyed in the 2015 earthquake. This unique temple, also known as the Maru Sattal, was built in 1596 by King Lakshminarasimha Malla, the entire structure contained no iron nails or supports and was made entirely from wood. Legend has it that the used for this two-story pagoda was obtained from a single tree. The Kathmandu Valley may have been inhabited as early as 300 BCE, the earliest known inscription is dated 185 CE. The oldest firmly dated building in the valley is almost 1,992 years old. As with the tales of the Buddhas visit, there is no evidence supporting Ashoks visit, the Licchavis, whose earliest inscriptions date to 464, were the next rulers of the valley and had close ties with the Gupta Empire of India. His victory in the Battle of Kirtipur was the beginning of his conquest of the valley, the Newars are the indigenous inhabitants and the creators of the historic civilization of the valley. The language is known as Nepal Bhasa. They are understood to be the descendants of the various ethnic, scholars have also described the Newars as a nation. They have developed a division of labour and an urban civilization not seen elsewhere in the Himalayan foothills. They are known for their contributions to art, sculpture, architecture, culture, literature, music, industry, trade, agriculture and cuisine, newa architecture consists of the pagoda, stupa, shikhara, chaitya and other styles. The valleys trademark is the pagoda which may have originated in this area and spread to India, China, Indochina
26.
Reverse osmosis
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Reverse osmosis is a water purification technology that uses a semipermeable membrane to remove ions, molecules, and larger particles from drinking water. In reverse osmosis, a pressure is used to overcome osmotic pressure, a colligative property, that is driven by chemical potential differences of the solvent. Reverse osmosis can remove many types of dissolved and suspended species from water, including bacteria, the result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be selective, this membrane should not allow large molecules or ions through the pores, in the normal osmosis process, the solvent naturally moves from an area of low solute concentration, through a membrane, to an area of high solute concentration. Applying an external pressure to reverse the flow of pure solvent. The process is similar to other membrane technology applications, however, key differences are found between reverse osmosis and filtration. Reverse osmosis also involves diffusion, making the process dependent on pressure, flow rate, reverse osmosis is most commonly known for its use in drinking water purification from seawater, removing the salt and other effluent materials from the water molecules. The process of osmosis through semipermeable membranes was first observed in 1748 by Jean-Antoine Nollet, for the following 200 years, osmosis was only a phenomenon observed in the laboratory. In 1950, the University of California at Los Angeles first investigated desalination of seawater using semipermeable membranes, cadottes patent on this process was the subject of litigation and has since expired. Almost all commercial reverse osmosis membrane is now made by this method, by the end of 2001, about 15,200 desalination plants were in operation or in the planning stages, worldwide. In 1977 Cape Coral, Florida became the first municipality in the United States to use the RO process on a scale with an initial operating capacity of 3 million gallons per day. By 1985, due to the growth in population of Cape Coral. In most cases, the membrane is designed to only water to pass through this dense layer. This process is best known for its use in desalination, but since the early 1970s, it has also used to purify fresh water for medical, industrial. Around the world, household drinking water systems, including a reverse osmosis step, are commonly used for improving water for drinking and cooking. CTA membrane is a paper by-product membrane bonded to a layer and are made to allow contact with chlorine in the water. These require an amount of chlorine in the water source to prevent bacteria from forming on it. The typical rejection rate for CTA membranes is 85–95%, the cellulose triacetate membrane is prone to rotting unless protected by chlorinated water, while the thin film composite membrane is prone to breaking down under the influence of chlorine
27.
Ion exchange
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Ion exchange is an exchange of ions between two electrolytes or between an electrolyte solution and a complex. In most cases the term is used to denote the processes of purification, separation, typical ion exchangers are ion exchange resins, zeolites, montmorillonite, clay, and soil humus. Ion exchangers are either cation exchangers that exchange positively charged ions or anion exchangers that exchange negatively charged ions, there are also amphoteric exchangers that are able to exchange both cations and anions simultaneously. Ion exchanges can be unselective or have binding preferences for certain ions or classes of ions and this can be dependent on the size of the ions, their charge, or their structure. Along with absorption and adsorption, ion exchange is a form of sorption, Ion exchange is a reversible process and the ion exchanger can be regenerated or loaded with desirable ions by washing with an excess of these ions. Ion exchange is a widely used in household to produce soft water. This is accomplished by exchanging calcium Ca2+ and magnesium Mg2+ cations against Na+ or H+ cations, another application for ion exchange in domestic water treatment is the removal of nitrate and natural organic matter. Industrial and analytical ion exchange chromatography is another area to be mentioned, Ion exchange chromatography is a chromatographical method that is widely used for chemical analysis and separation of ions. For example, in biochemistry it is used to separate charged molecules such as proteins. An important area of the application is extraction and purification of biologically produced substances such as proteins, there are two series of rare earth metals, the lanthanides and the actinides, both of whose families all have very similar chemical and physical properties. Then, the plutonium and uranium are available for making nuclear-energy materials, such as new reactor fuel, the ion-exchange process is also used to separate other sets of very similar chemical elements, such as zirconium and hafnium, which is also very important for the nuclear industry. Zirconium is practically transparent to neutrons, used in building reactors. Ion exchangers are used in nuclear reprocessing and the treatment of radioactive waste, Ion exchange resins in the form of thin membranes are used in chloralkali process, fuel cells and vanadium redox batteries. Ion exchange can also be used to remove hardness from water by exchanging calcium and magnesium ions for sodium ions in an ion exchange column, liquid phase ion exchange desalination has been demonstrated. In this technique anions and cations in water are exchanged for carbonate anions. Calcium and carbonate ions react to form calcium carbonate, which then precipitates leaving behind fresh water. The desalination occurs at ambient temperature and pressure and requires no membranes or solid ion exchangers, theoretical energy efficiency of this method is on par with electrodialysis and reverse osmosis. In soil science, cation exchange capacity is the ion exchange capacity of soil for positively charged ions, soils can be considered as natural weak cation exchangers
28.
Activated alumina
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Activated alumina is manufactured from aluminium hydroxide by dehydroxylating it in a way that produces a highly porous material, this material can have a surface area significantly over 200 m²/g. The compound is used as a desiccant and as a filter of fluoride, arsenic and it is made of aluminium oxide, the same chemical substance as sapphire and ruby. It has a very high ratio, due to the many tunnel like pores that it has. Used as a desiccant, it works by a process called adsorption, the water in the air actually sticks to the alumina itself in between the tiny passages as the air passes through them. The water molecules become trapped so that the air is dried out as it passes through the filter, if the alumina desiccant is heated to ~200 °C, it will release the trapped water. This process is called regenerating the desiccant, Activated alumina is also widely used to remove fluoride from drinking water. In the US, there are programs to fluoridate drinking water. However, in regions, such as the Rajasthan region of India. A study from the Harvard school of Public Health found exposure to fluoride as a child correlated with lower IQ, Activated alumina filters can easily reduce fluoride levels from 10.0 ppm to less than 1.0 ppm. The amount of fluoride leached from the water being filtered depends on how long the water is actually touching the alumina filter media, basically, the more alumina in the filter, the less fluoride will be in the final, filtered water. Lower temperature water, and lower pH water are filtered more effectively too, ideal pH for treatment is 5.5, which allows for up to a 95% removal rate. As per researches conducted by V. K. Chhabra Activated alumina, the fluoride uptake capacity of activated alumina can be up to 5000 mg/kg. The FUC can be determined as follows, V. K. Chhabra’s method, Fluoride solution, Dissolve 22.1 g anhydrous NaF in distilled water,10 mL/L =100 mg/L fluoride. Procedure, To one litre of simulated distilled water containing 100 mg/L of fluoride, add 10 g of the AA under test. After one hour, switch off the machine and take out the solution, after 5 minutes, carefully decant the supernatant solution and determine the fluoride. Calculate the difference between the original and treated water fluoride concentration, multiply the difference by 100 to give the fluoride uptake capacity of AA in mg/kg. In high vacuum applications, activated alumina is used as a material in fore-line traps to prevent oil generated by rotary vane pumps from back streaming into the system. Its mechanical properties and non-reactivity in the environment allow it to be a suitable material used to cover surfaces in friction in body prostheses
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Chaff
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Chaff is the dry, scaly protective casings of the seeds of cereal grain, or similar fine, dry, scaly plant material such as scaly parts of flowers, or finely chopped straw. Chaff is indigestible by humans, but livestock can eat it and in agriculture it is used as livestock fodder, chaff comes from Middle English chaf, from Old English ceaf, related to Old High German cheva, husk. In grasses, the seed is surrounded by thin, dry, scaly bracts. Once it is removed it is referred to as chaff. In wild cereals and in the primitive domesticated einkorn, emmer and spelt wheats, before the grain can be used, the husks must be removed. The process of loosening the chaff from the grain so as to remove it is called threshing – traditionally done by milling or pounding. Separating remaining loose chaff from the grain is called winnowing – traditionally done by repeatedly tossing the grain up into a wind which gradually blows the lighter chaff away. This method typically utilizes a broad, plate-shaped basket or similar receptacle to hold, domesticated grains such as durum wheat and common wheat have been bred to have chaff that is easily removed. These varieties are known as free-threshing or naked, chaff should not be confused with bran, which is finer scaly material that is part of the grain itself. Chaff is also made by chopping straw into short lengths. Like grain chaff this is used as feed, and is a way of turning coarse fodder into a form more palatable to livestock. In botany, chaff refers to the thin receptacular bracts of many species in the sunflower family Asteraceae and they are modified scale-like leaves surrounding single florets in the flower-head. Chaff as a product from grain processing leads to a metaphorical use of the term. Compare also the Parable of the Tares, which refers to a mixture of wheat, another example is in Psalm 1,4 of the Bible, which says, The ungodly are not so, but are like the chaff which the wind driveth away. Hungarian engineer László Schremmer has recently discovered that by the use of chaff-based filters it is possible to reduce the content of water to 3 microgram/litre. This is especially important in areas where the water is provided by filtering the water extracted from the underground aquifer. Bran Biomass Combine harvester Rice hulls Rice huller Threshing Threshing machine Winnowing
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Aquifer
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An aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials from which groundwater can be extracted using a water well. The study of flow in aquifers and the characterization of aquifers is called hydrogeology. Related terms include aquitard, which is a bed of low permeability along an aquifer, and aquiclude, if the impermeable area overlies the aquifer, pressure could cause it to become a confined aquifer. Aquifers may occur at various depths and those closer to the surface are not only more likely to be used for water supply and irrigation, but are also more likely to be topped up by the local rainfall. Many desert areas have limestone hills or mountains within them or close to them that can be exploited as groundwater resources, overexploitation can lead to the exceeding of the practical sustained yield, i. e. more water is taken out than can be replenished. The beach provides a model to help visualize an aquifer, if a hole is dug into the sand, very wet or saturated sand will be located at a shallow depth. This hole is a well, the wet sand represents an aquifer. In 2013 large freshwater aquifers were discovered under continental shelves off Australia, China, North America and they contain an estimated half a million cubic kilometers of “low salinity” water that could be economically processed into potable water. The reserves formed when ocean levels were lower and rainwater made its way into the ground in areas that were not submerged until the ice age ended 20,000 years ago. The volume is estimated to be 100x the amount of extracted from other aquifers since 1900. The above diagram indicates typical flow directions in a view of a simple confined or unconfined aquifer system. The system shows two aquifers with one aquitard between them, surrounded by the bedrock aquiclude, which is in contact with a gaining stream, the water table and unsaturated zone are also illustrated. An aquitard is a zone within the earth that restricts the flow of groundwater from one aquifer to another, an aquitard can sometimes, if completely impermeable, be called an aquiclude or aquifuge. Aquitards are composed of layers of clay or non-porous rock with low hydraulic conductivity. Groundwater can be found at every point in the Earths shallow subsurface to some degree. Saturated means the head of the water is greater than atmospheric pressure. The definition of the table is the surface where the pressure head is equal to atmospheric pressure. Unsaturated conditions occur above the table where the pressure head is negative
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Bangladesh
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Bangladesh, officially the Peoples Republic of Bangladesh, is a country in South Asia. It shares land borders with India and Myanmar, Nepal, Bhutan and China are located near Bangladesh but do not share a border with it. The countrys maritime territory in the Bay of Bengal is roughly equal to the size of its land area, Bangladesh is the worlds eighth most populous country. Dhaka is its capital and largest city, followed by Chittagong which has the countrys largest port, Bangladesh forms the largest and eastern part of the Bengal region. Bangladeshis include people of different ethnic groups and religions, Bengalis, who speak the official Bengali, make up 98% of the population. The politically dominant Bengali Muslims make the nation the worlds third largest Muslim-majority country, most of Bangladesh is covered by the Bengal delta, the largest delta on Earth. The country has 700 rivers and 8,046 km of inland waterways, highlands with evergreen forests are found in the northeastern and southeastern regions of the country. Bangladesh has many islands and a coral reef and it is home to the Sundarbans, the largest mangrove forest in the world. The countrys biodiversity includes a vast array of plant and wildlife, including critically endangered Bengal tigers, the Greeks and Romans identified the region as Gangaridai, a powerful kingdom of the historical subcontinent, in the 3rd century BCE. Archaeological research has unearthed several ancient cities in Bangladesh, which had trade links for millennia. The Bengal Sultanate and Mughal Bengal transformed the region into a cosmopolitan Islamic imperial power between the 14th and 18th centuries, the region was home to many principalities which had inland naval prowess. It was also a center of the worldwide muslin and silk trade. As part of British India, the region was influenced by the Bengali renaissance, the Partition of British India made East Bengal a part of the Dominion of Pakistan, and was renamed as East Pakistan. The region witnessed the Bengali Language Movement in 1952 and the Bangladesh Liberation War in 1971, after independence, a parliamentary republic was established. A presidential government was in place between 1975 and 1990, followed by a return to parliamentary democracy, the country has also been affected by poverty, natural disasters, hunger, dominant party systems and military coups. Bangladesh is a power and a major developing nation. Listed as one of the Next Eleven, it has the 46th largest economy and it is one of the largest textile exporters in the world. Its major trading partners are the European Union, the United States, China, India, Japan, Malaysia, with its strategically vital location between Southern, Eastern and Southeast Asia, Bangladesh is an important promoter of regional connectivity and cooperation
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Flocculation
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Flocculation, in the field of chemistry, is a process wherein colloids come out of suspension in the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid, in the flocculated system, there is no formation of a cake, since all the flocs are in the suspension. According to the IUPAC definition, flocculation is a process of contact, flocculation is synonymous with agglomeration and coagulation / coalescence. Basically, coagulation is a process of addition of coagulant to destabilize a stabilized charged particle, meanwhile, flocculation is a mixing technique that promotes agglomeration and assists in the settling of particles. The most common used coagulant is alum, Al23•14H2O, flocculation is affected by several parameters, including mixing speeds, mixing intensity, and mixing time. The product of the intensity and mixing time is used to describe flocculation processes. In colloid chemistry, flocculation refers to the process by which fine particulates are caused to clump together into a floc, the floc may then float to the top of the liquid, settle to the bottom of the liquid, or be readily filtered from the liquid. Flocculation behavior of soil colloids is closely related to freshwater quality, for emulsions, flocculation describes clustering of individual dispersed droplets together, whereby the individual droplets do not lose their identity. Flocculation is thus the initial step leading to further ageing of the emulsion, flocculation is used in mineral dressing. In civil engineering, and in the sciences, flocculation is a condition in which clays, polymers or other small charged particles become attached and form a fragile structure. Flocculation is used in applications in conjunction with microfiltration to improve the efficiency of biological feeds. The addition of synthetic flocculants to the bioreactor can increase the particle size making microfiltration more efficient. When flocculants are not added, cakes form and accumulate causing low cell viability, positively charged flocculants work better than negatively charged ones since the cells are generally negatively charged. Flocculation is widely employed to measure the progress of curd formation in the stages of cheese making to determine how long the curds must set. The reaction involving the rennet micelles are modeled by Smoluchowski kinetics, during the renneting of milk the micelles can approach one another and flocculate, a process that involves hydrolysis of molecules and macropeptides. Flocculation is also used during cheese wastewater treatment, three different coagulants are mainly used, FeSO4 Al23 FeCl3 In the brewing industry flocculation has a different meaning. It is an important process in fermentation during the production of beer where cells form macroscopic flocs. These flocs cause the yeast to sediment or rise to the top of a fermentation at the end of the fermentation, subsequently, the yeast can be collected from the top or the bottom of the fermenter in order to be reused for the next fermentation
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Coprecipitation
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In chemistry, coprecipitation or co-precipitation is the carrying down by a precipitate of substances normally soluble under the conditions employed. Analogously, in medicine, coprecipitation is specifically the precipitation of an unbound antigen along with an antigen-antibody complex, coprecipitation is an important issue in chemical analysis, where it is often undesirable, but in some cases it can be exploited. This problem can often be mitigated by digestion or by redissolving the sample, on the other hand, in the analysis of trace elements, as is often the case in radiochemistry, coprecipitation is often the only way of separating an element. An example is the separation of francium from other elements by coprecipitating it with caesium salts such as caesium perchlorate. Otto Hahn is credited for promoting the use of coprecipitation in radiochemistry, there are three main mechanisms of coprecipitation, inclusion, occlusion, and adsorption. An adsorbate is an impurity that is bound to the surface of the precipitate. An occlusion occurs when an adsorbed impurity gets physically trapped inside the crystal as it grows, coprecipitation is also used as a method of magnetic nanoparticle synthesis. For D and λ greater than unity, the precipitate is enriched in the tracer, depending on the co-precipitation system and conditions either λ or D may be constant. The derivation of the Doerner-Hoskins law assumes that there in no mass exchange between the interior of the crystals and the solution. When this assumption is fulfilled, then the content of the tracer in the crystal is non-uniform, when the Berthelot-Nernst law applies, then the concentration of the tracer in the interior of the crystal is uniform. This is the case when diffusion in the interior is possible or when the small crystals are allowed to recrystalize
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Alum
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Alum /ˈælum/ is both a specific chemical compound and a class of chemical compounds. The specific compound is the potassium aluminium sulfate with the formula KAl2·12H 2O. When the trivalent ion is aluminium, the alum is named after the monovalent ion, alums are useful for a range of industrial processes. They are soluble in water, have a taste, react acid to litmus. In alums each metal ion is surrounded by six water molecules, when heated, they liquefy, and if the heating is continued, the water of crystallization is driven off, the salt froths and swells, and at last an amorphous powder remains. The most important members - potassium, sodium, and ammonium - are produced industrially, typical recipes involve combining alumina, sulfuric acid, and the sulfate second cation, potassium, sodium, or ammonium. Potassium alum has been used at least since Roman times for purification of drinking water, Alum solution has the property of dissolving steels while not affecting aluminium or base metals, and can be used to recover workpieces made in these metals with broken toolbits lodged inside them. Alum in block form can be used as a blood coagulant, styptic pencils containing aluminium sulfate or potassium aluminium sulfate are used as astringents to prevent bleeding from small shaving cuts. Alum may be used in depilatory waxes used for the removal of hair or applied to freshly waxed skin as a soothing agent. In the 1950s, men sporting crewcut or flattop hairstyles sometimes applied alum to their hair as an alternative to pomade, when the hair dried, it would stay up all day. Alums antiperspirant and antibacterial properties contribute to its use as an underarm deodorant. It has been used for purpose in Europe, Mexico, Thailand, throughout Asia. Today, potassium or ammonium alum is sold commercially for this purpose as a deodorant crystal, Alum powder, found in the spice section of many grocery stores, may be used in pickling recipes as a preservative to maintain fruit and vegetable crispness. Alum is used as the component of some commercial baking powders. Alum was used by bakers in England during the 1800s to make bread whiter and this was thought by some, without adequate scientific grounds, to cause rickets. The Sale of Food and Drugs Act 1875 prevented this and other adulterations, solutions containing alum may be used to treat cloth, wood, and paper materials to increase their resistance to fire. Alum is used to water by neutralizing the electrical double layer surrounding very fine suspended particles. After flocculation, the particles will be enough to settle
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Water softening
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Water softening is the removal of calcium, magnesium, and certain other metal cations in hard water. The resulting soft water is more compatible with soap and extends the lifetime of plumbing, water softening is usually achieved using lime softening or ion-exchange resins. The presence of metal ions like calcium and magnesium principally as bicarbonates, chlorides. Hard water leads to the buildup of limescale, which can foul plumbing, in industrial scale water softening plants, the effluent flow from the re-generation process can precipitate scale that can interfere with sewage systems. The slippery feeling experienced when using soap with soft water occurs because soaps tend to bind to fats in the layers of skin. The most common means for removing water hardness rely on ion-exchange resin or reverse osmosis, other approaches include precipitation methods and sequestration by the addition of chelating agents. Conventional water-softening appliances intended for household use depend on a resin in which hardness ions - mainly Ca2+ and Mg2+ - are exchanged for sodium ions. As described by NSF/ANSI Standard 44, ion-exchange devices reduce the hardness by replacing magnesium and calcium with sodium or potassium ions, ion exchange resins are organic polymers containing anionic functional groups to which the divalent cations bind more strongly than monovalent cations. Inorganic materials called zeolites also exhibit ion-exchange properties and these minerals are widely used in laundry detergents. Resins are also available to remove carbonate, bi-carbonate and sulfate ions which are absorbed, for anionic resins, regeneration typically uses a solution of sodium hydroxide or potassium hydroxide. The waste waters eluted from the column containing the unwanted calcium and magnesium salts are typically discharged to the sewage system. Lime softening is the process in which lime is added to water to make it softer. It has several advantages over the method but requires full-time. Chelators are used in analysis, as water softeners, and are ingredients in many commercial products such as shampoos. Citric acid is used to water in soaps and laundry detergents. A commonly used synthetic chelator is ethylenediaminetetraacetic acid, since Ca2+ and Mg2+ exist as nonvolatile salts, they can be removed by distilling the water. Distillation is too expensive in most cases, rainwater is soft because it is naturally distilled during the water cycle of evaporation, condensation and precipitation. Reverse osmosis takes advantage of pressure gradients across a special membrane
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Arsenic trioxide
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Arsenic trioxide is an inorganic compound with the formula As 2O3. This commercially important oxide of arsenic is the precursor to other arsenic compounds. Approximately 50,000 tonnes are produced annually, many applications are controversial given the high toxicity of arsenic compounds. Arsenic trioxide can be generated via processing of arsenic compounds including the oxidation of arsenic. Illustrative is the roasting of orpiment, an arsenic sulfide ore. 2 As 2S3 +9 O2 →2 As 2O3 +6 SO2 Most arsenic oxide is, however, for example, arsenopyrite, a common impurity in gold- and copper-containing ores, liberates arsenic trioxide upon heating in air. The processing of minerals has led to numerous cases of poisonings. Only in China are arsenic ores intentionally mined, in the laboratory, it is prepared by hydrolysis of arsenic trichloride,2 AsCl3 +3 H2O → As2O3 +6 HCl As 2O3 occurs naturally as two minerals, arsenolite and claudetite. Both are relatively rare secondary minerals found in zones of As-rich ore deposits. Sheets of As2O3 stand for part of structures of the recently discovered minerals lucabindiite, As4O6, Arsenic trioxide is an amphoteric oxide, and its aqueous solutions are weakly acidic. Thus, it dissolves readily in alkaline solutions to give arsenites and it is less soluble in acids, although it will dissolve in hydrochloric acid. Reduction gives elemental arsenic or arsine depending on conditions, As2O3 +6 Zn +12 HNO3 →2 AsH3 +6 Zn2 +3 H2O This reaction is used in the Marsh test. In the liquid and gas phase below 800 °C, arsenic trioxide has the formula As 4O6 and is isostructural with P 4O6, above 800 °C As 4O6 significantly dissociates into molecular As 2O3, which adopts the same structure as N 2O3. Three forms are known in the state, a high temperature cubic As 4O6, containing molecular As 4O6. The polymers, which both crystallize as monoclinic crystals, feature sheets of pyramidal AsO3 units that share O atoms, large scale applications include its use as a precursor to forestry products, in colorless glass production, and in electronics. Being the main compound of arsenic, the trioxide is the precursor to elemental arsenic, arsenic alloys, organoarsenic compounds, e. g. feed additives and pharmaceuticals, are derived from arsenic trioxide. Bulk arsenic-based compounds sodium arsenite and sodium cacodylate are derived from the trioxide, a variety of applications exploit arsenics toxicity, including the use of the oxide as a wood preservative. Copper arsenates, which are derived from arsenic trioxide, are used on a scale as a wood preservative in the US and Malaysia
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Electrodialysis
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Electrodialysis is used to transport salt ions from one solution through ion-exchange membranes to another solution under the influence of an applied electric potential difference. This is done in a configuration called an electrodialysis cell, the cell consists of a feed compartment and a concentrate compartment formed by an anion exchange membrane and a cation exchange membrane placed between two electrodes. Electrodialysis processes are different from distillation techniques and other membrane based processes in that species are moved away from the feed stream rather than the reverse. Because the quantity of dissolved species in the stream is far less than that of the fluid. Under the influence of a potential difference, the negatively charged ions in the dilute stream migrate toward the positively charged anode. The positively charged species in the D stream migrate toward the negatively charged cathode and these cations also stay in the C stream, prevented from further migration toward the cathode by the positively charged anion exchange membrane. As a result of the anion and cation migration, electric current flows between the cathode and anode, only an equal number of anion and cation charge equivalents are transferred from the D stream into the C stream and so the charge balance is maintained in each stream. The overall result of the process is an ion concentration increase in the concentrate stream with a depletion of ions in the dilute solution feed stream see video. The E stream is the stream that flows past each electrode in the stack. This stream may consist of the composition as the feed stream or may be a separate solution containing a different species. Depending on the configuration, anions and cations from the electrode stream may be transported into the C stream. In each case, this transport is necessary to carry current across the stack, reactions take place at each electrode. These gases are typically subsequently dissipated as the E stream effluent from each electrode compartment is combined to maintain a neutral pH, however, some have proposed collection of hydrogen gas for use in energy production. Current efficiency is a measure of how effective ions are transported across the ion exchange membranes for a given applied current, typically current efficiencies >80% are desirable in commercial stacks to minimize energy operating costs. Current efficiency is generally a function of feed concentration, in application, electrodialysis systems can be operated as continuous production or batch production processes. In a continuous process, feed is passed through a sufficient number of stacks placed in series to produce the desired product quality. In batch processes, the diluate and/or concentrate streams are re-circulated through the systems until the final product or concentrate quality is achieved. Electrodialysis is usually applied to deionization of aqueous solutions, however, desalting of sparingly conductive aqueous organic and organic solutions is also possible
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Total dissolved solids
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Total dissolved solids is a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or micro-granular suspended form. Generally the operational definition is that the solids must be enough to survive filtration through a filter with two-micrometer pores. Total dissolved solids are normally discussed only for systems, as salinity includes some of the ions constituting the definition of TDS. The chemicals may be cations, anions, molecules or agglomerations on the order of one thousand or fewer molecules, more exotic and harmful elements of TDS are pesticides arising from surface runoff. Certain naturally occurring total dissolved solids arise from the weathering and dissolution of rocks, the United States has established a secondary water quality standard of 500 mg/l to provide for palatability of drinking water. Total dissolved solids are differentiated from total suspended solids, in that the latter cannot pass through a sieve of two micrometers and yet are indefinitely suspended in solution. The term settleable solids refers to material of any size that will not remain suspended or dissolved in a holding tank not subject to motion, settleable solids may include larger particulate matter or insoluble molecules. The two principal methods of measuring total dissolved solids are gravimetric analysis and conductivity, gravimetric methods are the most accurate and involve evaporating the liquid solvent and measuring the mass of residues left. This method is generally the best, although it is time-consuming, if inorganic salts comprise the great majority of TDS, gravimetric methods are appropriate. Electrical conductivity of water is related to the concentration of dissolved ionized solids in the water. Ions from the solids in water create the ability for that water to conduct an electric current. When correlated with laboratory TDS measurements, conductivity provides a value for the TDS concentration. The correlation factor ke varies between 0.55 and 0.8, hydrologic transport models are used to mathematically analyze movement of TDS within river systems. The most common models address surface runoff, allowing variation in land use type, topography, soil type, vegetative cover, precipitation, runoff models have evolved to a good degree of accuracy and permit the evaluation of alternative land management practices upon impacts to stream water quality. Basin models are used to more comprehensively evaluate total dissolved solids within a catchment basin, the DSSAM model was developed by the U. S. Environmental Protection Agency. This hydrology transport model is based upon the pollutant-loading metric called Total Maximum Daily Load. The success of this contributed to the Agency’s broadened commitment to the use of the underlying TMDL protocol in its national policy for management of many river systems in the United States. High levels of dissolved solids do not correlate to hard water
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Brine
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Brine is a solution of salt in water. In different contexts, brine may refer to salt solutions ranging from about 3. 5% up to about 26%, fahrenheit could reliably reproduce by freezing brine. By reference, seawater usually freezes at −2 °C, at 100 °C, saturated sodium chloride brine is about 28% salt by weight. At 0 °C, brine can only hold about 26% salt, the thermal conductivity of seawater is 0.6 W/mK at 25 °C. The majority of hydrogen produced through electrolysis is a side product in the production of chlorine. 2 NaCl +2 H2O →2 NaOH + H2 + Cl2 Brine is a fluid used in large refrigeration installations for the transport of thermal energy from place to place. The lowest freezing point obtainable for NaCl brine is −21.1 °C at 23. 3wt% NaCl and this is called the eutectic point. In lower temperatures, a solution can be used to de-ice or reduce freezing temperatures on roads. In cooking, brine is used for food brining and salting, in hydrology, brine is a form of salt water, namely, water with relatively high concentration of salt. Brine mining Saline water Brackish water
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United Kingdom
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The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom or Britain, is a sovereign country in western Europe. Lying off the north-western coast of the European mainland, the United Kingdom includes the island of Great Britain, Northern Ireland is the only part of the United Kingdom that shares a land border with another sovereign state—the Republic of Ireland. The Irish Sea lies between Great Britain and Ireland, with an area of 242,500 square kilometres, the United Kingdom is the 78th-largest sovereign state in the world and the 11th-largest in Europe. It is also the 21st-most populous country, with an estimated 65.1 million inhabitants, together, this makes it the fourth-most densely populated country in the European Union. The United Kingdom is a monarchy with a parliamentary system of governance. The monarch is Queen Elizabeth II, who has reigned since 6 February 1952, other major urban areas in the United Kingdom include the regions of Birmingham, Leeds, Glasgow, Liverpool and Manchester. The United Kingdom consists of four countries—England, Scotland, Wales, the last three have devolved administrations, each with varying powers, based in their capitals, Edinburgh, Cardiff and Belfast, respectively. The relationships among the countries of the UK have changed over time, Wales was annexed by the Kingdom of England under the Laws in Wales Acts 1535 and 1542. A treaty between England and Scotland resulted in 1707 in a unified Kingdom of Great Britain, which merged in 1801 with the Kingdom of Ireland to form the United Kingdom of Great Britain and Ireland. Five-sixths of Ireland seceded from the UK in 1922, leaving the present formulation of the United Kingdom of Great Britain, there are fourteen British Overseas Territories. These are the remnants of the British Empire which, at its height in the 1920s, British influence can be observed in the language, culture and legal systems of many of its former colonies. The United Kingdom is a country and has the worlds fifth-largest economy by nominal GDP. The UK is considered to have an economy and is categorised as very high in the Human Development Index. It was the worlds first industrialised country and the worlds foremost power during the 19th, the UK remains a great power with considerable economic, cultural, military, scientific and political influence internationally. It is a nuclear weapons state and its military expenditure ranks fourth or fifth in the world. The UK has been a permanent member of the United Nations Security Council since its first session in 1946 and it has been a leading member state of the EU and its predecessor, the European Economic Community, since 1973. However, on 23 June 2016, a referendum on the UKs membership of the EU resulted in a decision to leave. The Acts of Union 1800 united the Kingdom of Great Britain, Scotland, Wales and Northern Ireland have devolved self-government
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