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Alkaline Soils
Alkali, or Alkaline, soils are clay soils with high pH (greater than 8.5), a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate, which causes the soil to swellManaging irrigation water quality, Oregon State University, USA Retrieved on 2012-10-04. and difficult to clarify/settle. They derive their name from the alkali metal group of elements, to which belong ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paddyfield
A paddy field is a flooded field (agriculture), field of arable land used for growing Aquatic plant, semiaquatic crops, most notably rice and taro. It originates from the Neolithic rice-farming cultures of the Yangtze River basin in southern China, associated with Austronesian peoples#Neolithic China, pre-Austronesian and Hmong–Mien languages, Hmong-Mien cultures. It was spread in prehistoric times by the Austronesian peoples#Austronesian expansion, expansion of Austronesian peoples to Island Southeast Asia, Southeast Asia including Northeastern India, Madagascar, Melanesia, Micronesia, and Polynesia. The technology was also acquired by other cultures in mainland Asia for rice farming, spreading to East Asia, Mainland Southeast Asia, and South Asia. Fields can be built into steep hillsides as Terrace (agriculture), terraces or adjacent to depressed or steeply sloped features such as rivers or marshes. They require a great deal of labor and materials to create and need l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fly Ash
Fly ash, flue ash, coal ash, or pulverised fuel ash (in the UK) plurale tantum: coal combustion residuals (CCRs)is a coal combustion product that is composed of the particulates (fine particles of burned fuel) that are driven out of coal-fired boilers together with the flue gases. Ash that falls to the bottom of the boiler's combustion chamber (commonly called a firebox) is called bottom ash. In modern coal-fired power plants, fly ash is generally captured by electrostatic precipitators or other particle filtration equipment before the flue gases reach the chimneys. Together with bottom ash removed from the bottom of the boiler, it is known as coal ash. Depending upon the source and composition of the coal being burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts of silicon dioxide (SiO2) (both amorphous and crystalline), aluminium oxide (Al2O3) and calcium oxide (CaO), the main mineral compounds in coal-bearing rock strata. The u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waste Heat
Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility (or in thermodynamics lexicon a lower exergy or higher entropy) than the original energy source. Sources of waste heat include all manner of human activities, natural systems, and all organisms, for example, incandescent light bulbs get hot, a refrigerator warms the room air, a building gets hot during peak hours, an internal combustion engine generates high-temperature exhaust gases, and electronic components get warm when in operation. Instead of being "wasted" by release into the ambient environment, sometimes waste heat (or cold) can be used by another process (such as using hot engine coolant to heat a vehicle), or a portion of heat that would otherwise be wasted can be reused in the same process if make-up heat is added to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooling Tower
A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream to a lower temperature. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or, in the case of ''dry cooling towers'', rely solely on air to cool the working fluid to near the dry-bulb air temperature using radiators. Common applications include cooling the circulating water used in oil refineries, petrochemical and other chemical plants, thermal power stations, nuclear power stations and HVAC systems for cooling buildings. The classification is based on the type of air induction into the tower: the main types of cooling towers are natural draft and induced draft cooling towers. Cooling towers vary in size from small roof-top units to very large hyperboloid structures (as in the adjacent image) that can be up to tall and in diameter, or rectangu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amazon River
The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile. The headwaters of the Apurímac River on Nevado Mismi had been considered for nearly a century as the Amazon basin's most distant source, until a 2014 study found it to be the headwaters of the Mantaro River on the Cordillera Rumi Cruz in Peru. The Mantaro and Apurímac rivers join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, forming what countries other than Brazil consider to be the main stem of the Amazon. Brazilians call this section the Solimões River above its confluence with the Rio Negro forming what Brazilians call the Amazon at the Meeting of Waters ( pt, Encontro das Águas) at Manaus, the largest city on the river. The Amazon River has an average discharge of about – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissolved Load
Dissolved load is the portion of a stream's total sediment load that is carried in solution, especially ions from chemical weathering. It is a major contributor to the total amount of material removed from a river's drainage basin, along with suspended load and bed load. The amount of material carried as dissolved load is typically much smaller than the suspended load, though this is not always the case, particularly when the available river flow is mostly harnessed for purposes such as irrigation or industrial uses. Dissolved load comprises a significant portion of the total material flux out of a landscape, and its composition is important in regulating the chemistry and biology of the stream water. The dissolved load is primarily controlled by the rate of chemical weathering, which depends on climate and weather conditions such as moisture and temperature. Dissolved load has many useful applications within the field of geology, including erosion, denudation, and reconstructing c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Chloride
Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g/mol respectively, 100 g of NaCl contains 39.34 g Na and 60.66 g Cl. Sodium chloride is the salt most responsible for the salinity of seawater and of the extracellular fluid of many multicellular organisms. In its edible form, salt (also known as ''table salt'') is commonly used as a condiment and food preservative. Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses. Another major application of sodium chloride is de-icing of roadways in sub-freezing weather. Uses In addition to the familiar domestic uses of salt, more dominant applications of the approximately 250 million tonnes per year production (2008 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hypochlorite
Sodium hypochlorite (commonly known in a dilute solution as bleach) is an Inorganic chemistry, inorganic chemical compound with the chemical formula, formula NaOCl (or NaClO), comprising a sodium cation () and a hypochlorite anion (or ). It may also be viewed as the sodium salt (chemistry), salt of hypochlorous acid. The anhydrous Chemical compound, compound is unstable and may decompose explosively. It can be crystallized as a hydrate, pentahydrate ·5, a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated. Sodium hypochlorite is most often encountered as a pale greenish-yellow dilute solution referred to as liquid bleach, which is a household chemical widely used (since the 18th century) as a disinfectant or a bleaching agent. In solution, the compound is unstable and easily decomposes, liberating chlorine, which is the active principle of such products. Sodium hypochlorite is the oldest and still most important chlorine-releasing compounds, chl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali that decomposes proteins at ordinary ambient temperatures and may cause severe chemical burns. It is highly soluble in water, and readily absorbs moisture and carbon dioxide from the air. It forms a series of hydrates . The monohydrate crystallizes from water solutions between 12.3 and 61.8 °C. The commercially available "sodium hydroxide" is often this monohydrate, and published data may refer to it instead of the anhydrous compound. As one of the simplest hydroxides, sodium hydroxide is frequently used alongside neutral water and acidic hydrochloric acid to demonstrate the pH scale to chemistry students. Sodium hydroxide is used in many industries: in the manufacture of pulp and paper, textiles, drinking water, soaps and deterge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Sulphate
Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 million tonnes, the decahydrate is a major commodity chemical product. It is mainly used as a filler in the manufacture of powdered home laundry detergents and in the Kraft process of paper pulping for making highly alkaline sulfides. Forms *Anhydrous sodium sulfate, known as the rare mineral thenardite, used as a drying agent in organic synthesis. *Heptahydrate sodium sulfate, a very rare form. *Decahydrate sodium sulfate, known as the mineral mirabilite, widely used by chemical industry. It is also known as Glauber's salt. History The decahydrate of sodium sulfate is known as Glauber's salt after the Dutch/German chemist and apothecary Johann Rudolf Glauber (1604–1670), who discovered it in Austrian spring water in 1625. He named it (mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during the late Carboniferous ( Pennsylvanian) and Permian times. Many significant coal deposits are younger than this and originate from the Mesozoic and Cenozoic eras. Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution. With the invention of the steam engine, coal consumption increased. In 2020, coal supplied about a quarter of the world's primary energy and over a third of its electricity. Some iron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hard Water
Hard water is water that has high mineral content (in contrast with "soft water"). Hard water is formed when water percolates through deposits of limestone, chalk or gypsum, which are largely made up of calcium and magnesium carbonates, bicarbonates and sulfates. Hard drinking water may have moderate health benefits. It can pose critical problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. In domestic settings, hard water is often indicated by a lack of foam formation when soap is agitated in water, and by the formation of limescale in kettles and water heaters.World Health OrganizatioHardness in Drinking-Water 2003 Wherever water hardness is a concern, water softening is commonly used to reduce hard water's adverse effects. Origins Natural rainwater, snow and other forms of precipitation typically have low concentrations of multivalent cations such as calcium and magnes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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