text stringlengths 11 320k | source stringlengths 26 161 |
|---|---|
Salt water chlorination is a process that uses dissolved salt (1000–4000 ppm or 1–4 g/L) for the chlorination of swimming pools and hot tubs . The chlorine generator (also known as salt cell, salt generator, salt chlorinator, or SWG) uses electrolysis in the presence of dissolved salt to produce chlorine gas or its dissolved forms, hypochlorous acid and sodium hypochlorite , which are already commonly used as sanitizing agents in pools. Hydrogen is produced as byproduct too.
The presence of chlorine in traditional swimming pools can be described as a combination of free available chlorine (FAC) and combined available chlorine (CAC). [ 1 ] While FAC is composed of the free chlorine that is available for disinfecting the water, the CAC includes chloramines , which are formed by the reaction of FAC with amines (introduced into the pool by human perspiration, saliva, mucus, urine, and other biologics, and by insects and other pests). [ 2 ] Chloramines are responsible for the "chlorine smell" of pools, as well as skin and eye irritation. These problems are the result of insufficient levels of free available chlorine, and indicate a pool that must be "shocked" by the addition of 5–10 times the normal amount of chlorine. [ 1 ] In saltwater pools, the generator uses electrolysis to continuously produce free chlorine. As such, a saltwater pool or hot tub is not actually chlorine-free; it simply utilizes added salt and a chlorine generator instead of direct addition of chlorine. It also burns off chloramines in the same manner as traditional shock (oxidizer). As with traditionally chlorinated pools, saltwater pools must be monitored in order to maintain proper water chemistry. Low chlorine levels can be caused by insufficient salt, incorrect (low) chlorine-generation setting on the SWG unit, higher-than-normal chlorine demand, low stabilizer, sun exposure, insufficient pump speed, or mechanical issues with the chlorine generator. Salt count can be lowered due to splash-out, backwashing, and dilution via rainwater.
Research has shown that because saltwater pools still use chlorine sanitization, they generate the same disinfection byproducts (DBPs) that are present in traditional pools. Of highest concern are haloketones and trihalomethanes (THMs) of those the predominant form being bromoform . Very high levels of bromoform—up to 1.3 mg per liter, or 13 times the World Health Organization 's guideline values—have been found in some public saltwater swimming pools. [ 3 ]
Manufacturers have been producing saltwater chlorine generators in the United States since the early 1980s, and they first appeared commercially in New Zealand in the early 1970s (the Aquatech IG4500). [ 4 ]
The chlorinator cell consists of parallel titanium plates coated with ruthenium and sometimes iridium . Older models make use of perforated (or mesh) plates rather than solid plates. Electrolysis naturally attracts calcium and other minerals to the plates. Thus, depending on water chemistry and magnitude of use, the cell will require periodic cleaning in a mild acid solution (1 part HCl to 15 parts water) which will remove the buildup of calcium compound crystals, such as calcium carbonate or calcium nitrate. Excessive buildup can reduce the effectiveness of the cell. Running the chlorinator for long periods with insufficient salt in the pool can strip the coating off the cell which then requires an expensive [ clarification needed ] replacement, as can using too strong an acid wash.
Saltwater pools can also require stabilizer ( cyanuric acid ) to help stop the sun's UV rays from breaking down free chlorine in the pool. Usual levels are 20–50 ppm. They also require the pH to be kept between 7.2 and 7.8 with the chlorine being more effective if the pH is kept closer to 7.2. The average salt levels are usually in the 3000-5000 ppm range, much less than the ocean, which has salt levels of around 35,000 ppm. [ 5 ] In swimming pools, salt is typically poured across the bottom and swept with the pool brush until it dissolves; if concentrated brine is allowed into the return-water system it can cause the chlorinator cell to malfunction due to overconductivity.
Salt water chlorination produces an excess of hydroxide ions, and this requires the frequent addition of hydrochloric acid (HCl, also known as muriatic acid ) to maintain pH. [ 6 ]
The benefits of salt systems in pools are the convenience and the constant delivery of pure chlorine-based sanitizer. The reduction of irritating chloramines versus traditional chlorinating methods and the "softening" effect of electrolysis reducing dissolved alkali minerals in the water are also perceived as benefits. For some people that have sensitivities to chlorine, these systems may be less offensive.
Disadvantages are the initial cost of the system, maintenance , and the cost of replacement cells. Salt is corrosive and will damage some metals and some improperly-sealed stone. However, as the ideal saline concentration of a salt-chlorinated pool is very low (<3,500ppm, the threshold for human perception of salt by taste; seawater is about ten times this concentration), damage usually occurs due to improperly-maintained pool chemistry or improper maintenance of the electrolytic cell. Pool equipment manufacturers typically will not warrant stainless steel products damaged by saline pools.
Calcium and other alkali precipitate buildup will occur naturally on the cathode plate, and sometimes in the pool itself as " scaling ". Regular maintenance of the cell is necessary; failure to do so will reduce the effectiveness of the cell. Certain designs of saline chlorinators use a "reverse-polarity" method that will regularly switch the roles of the two electrodes between anode and cathode , causing this calcium buildup to dissolve off the accumulating electrode. Such systems reduce but do not eliminate the need to clean the electrolytic cell and the occurrence of calcium scale in the water.
As chlorine is generated, pH will rise causing the chlorine to be less effective. Many systems with chemistry automation can sense the rising pH and automatically introduce either CO 2 or hydrochloric acid in order to bring the pH back to the target level.Automation systems will also manage levels of sanitizer by monitoring the ORP or redox levels of the water. This allows only the needed amount of chlorine to be generated based on the demand.
Sodium bromide can be used instead of sodium chloride , which produces a bromine pool. The benefits and downsides are the same as those of a salt system. It is not necessary to use a chloride-based acid to balance the pH. Also, bromine is only effective as a sanitizer, not as an oxidizer, leaving a need for adding a "shock" such as hydrogen peroxide or any chlorine-based shock to burn off inorganic waste and free up combined bromines. This extra step is not needed in a sodium chloride system, as chlorine is effective as both a sanitizer and an oxidizer. A user would only need to "super chlorinate" or increase chlorine production of the cell occasionally. That would normally be less than once a week or after heavy bather loads. | https://en.wikipedia.org/wiki/Salt_water_chlorination |
In biology , saltation (from Latin saltus ' leap, jump ' ) is a sudden and large mutational change from one generation to the next, potentially causing single-step speciation . This was historically offered as an alternative to Darwinism . Some forms of mutationism were effectively saltationist, implying large discontinuous jumps.
Speciation, such as by polyploidy in plants, can sometimes be achieved in a single and in evolutionary terms sudden step. Evidence exists for various forms of saltation in a variety of organisms.
Prior to Charles Darwin most evolutionary scientists had been saltationists. [ 1 ] Jean-Baptiste Lamarck was a gradualist but similar to other scientists of the period had written that saltational evolution was possible. Étienne Geoffroy Saint-Hilaire endorsed a theory of saltational evolution that "monstrosities could become the founding fathers (or mothers) of new species by instantaneous transition from one form to the next." [ 2 ] Geoffroy wrote that environmental pressures could produce sudden transformations to establish new species instantaneously. [ 3 ] In 1864 Albert von Kölliker revived Geoffroy's theory that evolution proceeds by large steps, under the name of heterogenesis . [ 4 ]
With the publication of On the Origin of Species in 1859 Charles Darwin wrote that most evolutionary changes proceeded gradually.
From 1860 to 1880 saltation had a minority interest but by 1890 had become a major interest to scientists. [ 5 ] In their paper on evolutionary theories in the 20th century Levit et al wrote:
The advocates of saltationism deny the Darwinian idea of slowly and gradually growing divergence of character as the only source of evolutionary progress. They would not necessarily completely deny gradual variation, but claim that cardinally new ‘body plans’ come into being as a result of saltations (sudden, discontinuous and crucial changes, for example, the series of macromutations). The latter are responsible for the sudden appearance of new higher taxa including classes and orders, while small variation is supposed to be responsible for the fine adaptations below the species level. [ 6 ]
In the early 20th century a mechanism of saltation was proposed as large mutations . It was seen as a much faster alternative to the Darwinian concept of a gradual process of small random variations being acted on by natural selection . It was popular with early geneticists such as Hugo de Vries , who along with Carl Correns helped rediscover Gregor Mendel 's laws of inheritance in 1900, William Bateson , a British zoologist who switched to genetics, and early in his career Thomas Hunt Morgan . Some of these geneticists developed it into the mutation theory of evolution. [ 7 ] [ 8 ] There was also a debate over accounts of the evolution of mimicry and if they could be explained by gradualism or saltation. The geneticist Reginald Punnett supported a saltational theory in his book Mimicry in Butterflies (1915). [ 9 ]
The mutation theory of evolution held that species went through periods of rapid mutation, possibly as a result of environmental stress, that could produce multiple mutations, and in some cases completely new species, in a single generation. This mutationist view of evolution was later replaced by the reconciliation of Mendelian genetics with natural selection into a gradualistic framework for the neo-Darwinian synthesis. [ 10 ] It was the emergence of population thinking in evolution which forced many scientists to adopt gradualism in the early 20th century. According to Ernst Mayr , it wasn't until the development of population genetics in the neo-Darwinian synthesis in the 1940s that demonstrated the explanatory power of natural selection that saltational views of evolution were largely abandoned. [ 11 ]
Saltation was originally denied by the " modern synthesis " school of neo-Darwinism which favoured gradual evolution but has since been accepted due to recent evidence in evolutionary biology (see the current status section). [ 12 ] [ 13 ] [ 14 ] [ 15 ] In recent years there are some prominent proponents of saltation, including Carl Woese . Woese, and colleagues, suggested that the absence of RNA signature continuum between domains of bacteria , archaea , and eukarya constitutes a primary indication that the three primary organismal lineages materialized via one or more major evolutionary saltations from some universal ancestral state involving dramatic change in cellular organization that was significant early in the evolution of life, but in complex organisms gave way to the generally accepted Darwinian mechanisms. [ 16 ] The geneticist Barbara McClintock introduced the idea of " jumping genes ", chromosome transpositions that can produce rapid changes in the genome . [ 17 ]
Saltational speciation , also known as abrupt speciation, is the discontinuity in a lineage that occurs through genetic mutations, chromosomal aberrations or other evolutionary mechanisms that cause reproductively isolated individuals to establish a new species population. Polyploidy , karyotypic fission , symbiogenesis and lateral gene transfer are possible mechanisms for saltational speciation. [ 18 ]
The botanist John Christopher Willis proposed an early saltationist theory of evolution. He held that species were formed by large mutations, not gradual evolution by natural selection. [ 19 ] [ 20 ]
The German geneticist Richard Goldschmidt was the first scientist to use the term "hopeful monster". Goldschmidt thought that small gradual changes could not bridge the hypothetical divide between microevolution and macroevolution. In his book The Material Basis of Evolution (1940) he wrote "the change from species to species is not a change involving more and more additional atomistic changes, but a complete change of the primary pattern or reaction system into a new one, which afterwards may again produce intraspecific variation by micromutation." Goldschmidt believed the large changes in evolution were caused by macromutations (large mutations). His ideas about macromutations became known as the hopeful monster hypothesis which is considered a type of saltational evolution. [ 21 ]
Goldschmidt's thesis however was universally rejected and widely ridiculed within the biological community, which favored the neo-Darwinian explanations of R.A. Fisher , J. B. S. Haldane and Sewall Wright . [ 22 ] However, there has been a recent interest in the ideas of Goldschmidt in the field of evolutionary developmental biology as some scientists are convinced he was not entirely wrong. [ 23 ]
Otto Schindewolf , a German paleontologist, also supported macromutations as part of his evolutionary theory. He was known for presenting an alternative interpretation of the fossil record based on his ideas of orthogenesis , saltational evolution and extraterrestrial impacts opposed to gradualism but abandoned the view of macromutations in later publications. [ 24 ]
Søren Løvtrup , a biochemist and embryologist from Denmark, advocated a similar hypothesis of macromutation to Goldschmidt's in 1974. [ 25 ] Lovtrup believed that macromutations interfered with various epigenetic processes, that is, those which affect the causal processes in biological development. This is in contrast to the gradualistic theory of micromutations of Neo-Darwinism , which claims that evolutionary innovations are generally the result of accumulation of numerous very slight modifications. Lovtrup also rejected the punctuated equilibria of Stephen Gould and Niles Eldredge , claiming it was a form of gradualism and not a macromutation theory. Lovtrup defended many of Darwin's critics including Schindewolf, Mivart , Goldschmidt, and Himmelfarb. [ 26 ] Mae Wan Ho described Lovtrup's theory as similar to the hopeful monster theory of Richard Goldschmidt . [ 25 ]
Goldschmidt presented two mechanisms for how hopeful monsters might work. One mechanism, involved “systemic mutations”, rejected the classical gene concept and is no longer considered by modern science; however, his second mechanism involved “developmental macromutations” in “rate genes” or “controlling genes” that change early development and thus cause large effects in the adult phenotype. These kind of mutations are similar to the ones considered in contemporary evolutionary developmental biology . [ 27 ]
On the subject of Goldschmidt Donald Prothero in his book Evolution: What the Fossils Say and Why It Matters (2007) wrote:
The past twenty years have vindicated Goldschmidt to some degree. With the discovery of the importance of regulatory genes, we realize that he was ahead of his time in focusing on the importance of a few genes controlling big changes in the organisms, not small-scales changes in the entire genome as neo-Darwinians thought. In addition, the hopeful monster problem is not so insurmountable after all. Embryology has shown that if you affect an entire population of developing embryos with a stress (such as a heat shock) it can cause many embryos to go through the same new pathway of embryonic development, and then they all become hopeful monsters when they reach reproductive age. [ 28 ]
In 2008 evolutionary biologist Olivia Judson in her article The Monster Is Back, and It’s Hopeful listed some examples which may support the hopeful monster hypothesis [ 29 ] and an article published in the journal Nature in 2010 titled Evolution: Revenge of the Hopeful Monster reported that studies in stickleback populations in a British Columbia lake and bacteria populations in a Michigan lab have shown that large individual genetic changes can have vast effects on organisms "without dooming it to the evolutionary rubbish heap". According to the article "Single-gene changes that confer a large adaptive value do happen: they are not rare, they are not doomed and, when competing with small-effect mutations, they tend to win. But small-effect mutations still matter — a lot. They provide essential fine-tuning and sometimes pave the way for explosive evolution to follow." [ 30 ]
A paper by (Page et al. 2010) have written that the Mexican axolotl ( Ambystoma mexicanum ) could be classified as a hopeful monster as it exhibits an adaptive and derived mode of development that has evolved rapidly and independently among tiger salamanders. According to the paper there has been an interest in aspects of the hopeful monster hypothesis in recent years:
Goldschmidt proposed that mutations occasionally yield individuals within populations that deviate radically from the norm and referred to such individuals as "hopeful monsters". If the novel phenotypes of hopeful monsters arise under the right environmental circumstances, they may become fixed, and the population will found a new species. While this idea was discounted during the Modern synthesis , aspects of the hopeful monster hypothesis have been substantiated in recent years. For example, it is clear that dramatic changes in phenotype can occur from few mutations of key developmental genes and phenotypic differences among species often map to relatively few genetic factors. These findings are motivating renewed interest in the study of hopeful monsters and the perspectives they can provide about the evolution of development. In contrast to mutants that are created in the lab, hopeful monsters have been shaped by natural selection and are therefore more likely to reveal mechanisms of adaptive evolution. [ 31 ]
Günter Theissen , a German professor of genetics , has classified homeotic mutants as "hopeful monsters" and has documented many examples of animal and plant lineages that may have originated in that way. [ 32 ] [ 33 ] American biologist Michael Freeling has proposed "balanced gene drive" as a saltational mechanism in the mutationist tradition, which could explain trends involving morphological complexity in plant and animal eukaryotic lineages. [ 34 ]
Examples of saltational evolution include cases of stabilized hybrids that can reproduce without crossing (such as allotetraploids ) and cases of symbiogenesis . Both gene duplication and lateral gene transfer have the capacity to bring about relatively large changes that are saltational. [ 35 ] Polyploidy (most common in plants but not unknown in animals) is saltational: a significant change (in gene numbers) can result in speciation in a single generation. [ 36 ]
Evidence of phenotypic saltation has been found in the centipede [ 37 ] and some scientists have suggested there is evidence for independent instances of saltational evolution in sphinx moths . [ 38 ] Saltational changes have occurred in the buccal cavity of the roundworm Caenorhabditis elegans . [ 39 ] Some processes of epigenetic inheritance can also produce changes that are saltational. [ 40 ] There has been a controversy over whether mimicry in butterflies and other insects can be explained by gradual or saltational evolution. [ 41 ] According to Norrström (2006) there is evidence for saltation in some cases of mimicry. [ 42 ] The endosymbiotic theory is considered to be a type of saltational evolution. [ 43 ] Symonds and Elgar, 2004 have suggested that pheromone evolution in bark beetles is characterized by large saltational shifts. [ 44 ] The mode of evolution of sex pheromones in Bactrocera has occurred by rapid saltational changes associated with speciation followed by gradual divergence thereafter. [ 45 ] Saltational speciation has been recognized in the genus Clarkia (Lewis, 1966). [ 46 ] It has been suggested (Carr, 1980, 2000) that the Calycadenia pauciflora could have originated directly from an ancestral race through a single saltational event involving multiple chromosome breaks. [ 47 ] Specific cases of homeosis in flowers can be caused by saltational evolution. In a study of divergent orchid flowers (Bateman and DiMichele, 2002) wrote how simple homeotic morphs in a population can lead to newly established forms that become fixed and ultimately lead to new species. [ 48 ] They described the transformation as a saltational evolutionary process, where a mutation of key developmental genes leads to a profound phenotypic change, producing a new evolutionary lineage within a species. [ 49 ]
Reviewing the history of macroevolutionary theories, the American evolutionary biologist Douglas J. Futuyma notes that since 1970, two very different alternatives to Darwinian gradualism have been proposed, both by Stephen Jay Gould : mutationism, and punctuated equilibria . [ 50 ] [ 51 ] Gould's macromutation theory gave a nod to his predecessor with an envisaged "Goldschmidt break" between evolution within a species and speciation. His advocacy of Goldschmidt was attacked with "highly unflattering comments" [ 50 ] by B. Charlesworth [ 52 ] and Templeton. [ 53 ] Futuyma concludes, following other biologists reviewing the field such as K.Sterelny [ 54 ] and A. Minelli, [ 55 ] that essentially all the claims of evolution driven by large mutations could be explained within the Darwinian evolutionary synthesis. [ 50 ] | https://en.wikipedia.org/wiki/Saltation_(biology) |
The Saltcellar with Portuguese Figures is a salt cellar in carved ivory , made in the Kingdom of Benin in West Africa in the 16th century, for the European market. It is attributed to an unknown master or workshop who has been given the name Master of the Heraldic Ship by art historians. It depicts four Portuguese figures, two of higher class and the other two are possibly guards protecting them. In the 16th century, Portuguese visitors ordered ivory salt cellars and ivory spoons similar to this object. This Afro-Portuguese ivory salt cellar was carved in the style of a Benin court ivory, comparable to the famous Benin bronzes and Benin ivory masks . [ 1 ]
These kinds of ivory arts were commissioned and exported initially from Sierra Leone and later Benin City , Nigeria. During the age of exploration European powers expanded their trade and efforts towards establishing trade posts in the New World , Africa, the Middle East and Asia. Portuguese sailors disembarked from their caravels to buy goods for trading like ivory , gold , and others. These goods were taken from markets to colonial outposts to Portugal and then traded within European markets. During the 16th and 17th century countries that participated in colonialism reaped the economical benefits from its international trade.
The salt cellar was probably carved for a Portuguese nobleman to put it on his dining table. It is one of four almost identical pieces, probably made as a set. The other three are now in European museums. [ 2 ] Ivory salt cellars and ivory spoons like the Sapi-Portuguese Ivory Spoon , also in the Metropolitan Museum of Art, were common pieces of art that Portuguese sailors brought back from West African countries. [ 3 ] There are no records of the order for this commission but it is believed that a Benin Ivory carver produced this in the Benin Kingdom, in modern day Nigeria .
The figures, in high relief form a circle around the shaft of the elephant tusk, supporting the bowl at top used to hold the salt. The amount and type of decoration indicates that this piece was created in a Benin court. Two of the four male figures are from clearly of a higher rank, probably from a higher class. They are more elaborately carved and shown frontally, while the other two have less ornament and are shown in profile. The men on the front and on the back are dressed with elaborate clothes with a cross necklace , showing they are European Christians . In addition they are wearing hats and holding spears in their left hand. [ 4 ]
The style used to carve the ivory piece may be intended to be somewhat grotesque. In Afro-Portuguese ivories there are three African elements that are fundamental to call a piece African art : a focus on the human figure, an enunciation of the parts and a preference for pure geometric forms. Individuals are presented as the main subject in African art usually depicting an important figure like royalty or a deity, this is shown in the ivory salt cellar and other Benin Bronzes . The faces of each man are bigger with their long beards and deep eyes than their body while keeping their proportions in check. The geometry of the pattern of the men's clothing, the socket of the spear is another example where this geometry is repeated. [ 5 ]
The kingdom of Benin existed in the southwestern region of Nigeria in modern Edo state , Nigeria. According to scholars the kingdom of Benin (also known as the Edo Kingdom, or the Benin Empire) originated around the year 900 by the Ogiso kings, it is said between the eleventh and the thirteenth a member from the Oba dynasty would take control of the state. [ 6 ] This dynasty would rule until 1897 when the British occupied the kingdom of Benin in February 9. The kingdom reached its peak during the rule of Ewuare the Great , he ruled from 1440 to 1473. King Ewuare expanded its natural borders and introduced wood and ivory carving to the kingdom. One of the first recorded visits to Benin City was made by Portuguese explorer, João Afonso de Aveiro in 1486. [ 7 ] After contact with the Portuguese the Benin Kingdom established a strong mercantile relationship with Portugal and later other European states. They traded slaves and Beninese products such as ivory, pepper , gold and palm oil for European goods such as manillas , metals and guns . In addition they established diplomatic relations in the late 15th century, the Oba sent an ambassador to Lisbon , and the king of Portugal sent Christian missionaries to Benin City in 1486. [ 8 ] | https://en.wikipedia.org/wiki/Saltcellar_with_Portuguese_Figures |
Salting in refers to the effect where increasing the ionic strength of a solution increases the solubility of a solute, such as a protein . This effect tends to be observed at lower ionic strengths . [ citation needed ]
Protein solubility is a complex function of physicochemical nature of the protein, pH, temperature, and the concentration of the salt used. It also depends on whether the salt is kosmotropic , whereby the salt will stabilize water. The solubility of proteins usually increases slightly in the presence of salt, referred to as "salting in". However, at high concentrations of salt, the solubility of the proteins drop sharply and proteins can precipitate out, referred to as "salting out". [ 1 ]
Initial salting in at low concentrations is explained by the Debye–Huckel theory . Proteins are surrounded by the salt counterions (ions of opposite net charge) and this screening results in decreasing electrostatic free energy of the protein and increasing activity of the solvent, which in turn leads to increasing solubility. This theory predicts that the logarithm of solubility is proportional to the square root of the ionic strength. [ citation needed ]
The behavior of proteins in solutions at high salt concentrations is explained by John Gamble Kirkwood . The abundance of the salt ions decreases the solvating power of salt ions, resulting in the decrease in the solubility of the proteins and precipitation results. [ citation needed ]
At high salt concentrations, the solubility is given by the following empirical expression. [ citation needed ]
where S is the solubility of the protein, B is a constant (function of protein, pH and temperature), K is the salting out constant (function of pH, mixing and salt), and I is the ionic strength of the salt. This expression is an approximation to that proposed by Long and McDevit. [ 2 ]
This chemistry -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Salting_in |
Salting out (also known as salt-induced precipitation , salt fractionation , anti-solvent crystallization , precipitation crystallization , or drowning out ) [ 1 ] is a purification technique that utilizes the reduced solubility of certain molecules in a solution of very high ionic strength . Salting out is typically used to precipitate large biomolecules, such as proteins or DNA. [ 2 ] Because the salt concentration needed for a given protein to precipitate out of the solution differs from protein to protein, a specific salt concentration can be used to precipitate a target protein. This process is also used to concentrate dilute solutions of proteins. Dialysis can be used to remove the salt if needed.
Salt compounds dissociate in aqueous solutions. This property is exploited in the process of salting out. When the salt concentration is increased, some of the water molecules are attracted by the salt ions , which decreases the number of water molecules available to interact with the charged part of the protein. [ 3 ]
There are hydrophobic amino acids and hydrophilic amino acids in protein molecules.
After protein folding in aqueous solution, hydrophobic amino acids usually form protected hydrophobic areas while hydrophilic amino acids interact with the molecules of solvation and allow proteins to form hydrogen bonds with the surrounding water molecules. If enough of the protein surface is hydrophilic, the protein can be dissolved in water. [ 4 ]
When salt is added to the solution, there is more frequent interaction between solvent molecules and salt ions. As a result, the protein and salt ions compete to interact with the solvent molecules with the result that there are fewer solvent molecules available for interaction with the protein molecules than before. The protein–protein interactions thus become stronger than the solvent–solute interactions and the protein molecules associate by forming hydrophobic interactions with each other. [ 5 ] After dissociation in a given solvent, the negatively charged atoms from a chosen salt begin to compete for interactions with positively charged molecules present in the solution. Similarly, the positively charged cations compete for interactions with the negatively charged molecules of the solvent. This process is known as salting out. [ citation needed ]
Soaps are easily precipitated by concentrated salt solution, the metal ion in the salt reacts with the fatty acids forming back the soap and glycerin (glycerol). To separate glycerin from the soap, the pasty boiling mass is treated with brine (NaCl solution). Contents of the kettle salt out (separate) into an upper layer that is a curdy mass of impure soap and a lower layer that consists of an aqueous salt solution with the glycerin dissolved in it. The slightly alkaline salt solution, termed spent lye, is extracted from the bottom of the pan or kettle and may be subsequently treated for glycerin recovery. [ citation needed ]
As different proteins have different compositions of amino acids, different protein molecules precipitate at different concentrations of salt solution. [ citation needed ]
Unwanted proteins can be removed from a protein solution mixture by salting out as long as the solubility of the protein in various concentrations of salt solution is known.
After removing the precipitate by filtration or centrifugation , the desired protein can be precipitated by altering the salt concentration to the level at which the desired protein becomes insoluble. [ 6 ]
One demerit of salting out in purification of proteins is that, in addition to precipitating a specific protein of interest, contaminants are also precipitated as well. Thus to obtain a purer protein of interest, additional purification methods such as ion exchange chromatography may be required. [ 7 ] | https://en.wikipedia.org/wiki/Salting_out |
Saltwater intrusion is the movement of saline water into freshwater aquifers , which can lead to groundwater quality degradation, including drinking water sources, and other consequences. Saltwater intrusion can naturally occur in coastal aquifers, owing to the hydraulic connection between groundwater and seawater . Because saline water has a higher mineral content than freshwater, it is denser and has a higher water pressure. As a result, saltwater can push inland beneath the freshwater. [ 1 ] In other topologies, submarine groundwater discharge can push fresh water into saltwater.
Certain human activities, especially groundwater pumping from coastal freshwater wells , have increased saltwater intrusion in many coastal areas. Water extraction drops the level of fresh groundwater, reducing its water pressure and allowing saltwater to flow further inland. Other contributors to saltwater intrusion include navigation channels or agricultural and drainage channels , which provide conduits for saltwater to move inland. Sea level rise caused by climate change also contributes to saltwater intrusion. [ 2 ] Saltwater intrusion can also be worsened by extreme events like hurricane storm surges . [ 3 ]
At the coastal margin, fresh groundwater flowing from inland areas meets with saline groundwater from the ocean. The fresh groundwater flows from inland areas towards the coast where elevation and groundwater levels are lower. [ 2 ] Because saltwater has a higher content of dissolved salts and minerals , it is denser than freshwater, causing it to have a higher hydraulic head than freshwater. Hydraulic head refers to the liquid pressure exerted by a water column: a water column with higher hydraulic head will move into a water column with lower hydraulic head, if the columns are connected. [ 4 ]
The higher pressure and density of saltwater causes it to move into coastal aquifers in a wedge shape under the freshwater. The saltwater and freshwater meet in a transition zone where mixing occurs through dispersion and diffusion . Ordinarily the inland extent of the saltwater wedge is limited because fresh groundwater levels, or the height of the freshwater column, increases as land elevation gets higher. [ 2 ]
Groundwater extraction is the primary cause of saltwater intrusion. Groundwater is the main source of drinking water in many coastal areas of the United States, and extraction has increased over time. Under baseline conditions, the inland extent of saltwater is limited by higher pressure exerted by the freshwater column, owing to its higher elevation. Groundwater extraction can lower the level of the freshwater table , reducing the pressure exerted by the freshwater column and allowing the denser saltwater to move inland laterally. [ 2 ] In Cape May, New Jersey , since the 1940s water withdrawals have lowered groundwater levels by up to 30 meters, reducing the water table to below sea level and causing widespread intrusion and contamination of water supply wells. [ 5 ] [ 6 ]
Groundwater extraction can also lead to well contamination by causing upwelling, or upcoming, of saltwater from the depths of the aquifer. [ 7 ] Under baseline conditions, a saltwater wedge extends inland, underneath the freshwater because of its higher density. Water supply wells located over or near the saltwater wedge can draw the saltwater upward, creating a saltwater cone that might reach and contaminate the well. Some aquifers are predisposed towards this type of intrusion, such as the Lower Floridan aquifer : though a relatively impermeable rock or clay layer separates fresh groundwater from saltwater, isolated cracks breach the confining layer, promoting upward movement of saltwater. Pumping of groundwater strengthens this effect by lowering the water table, reducing the downward push of freshwater. [ 6 ]
The construction of canals and drainage networks can lead to saltwater intrusion. Canals provide conduits for saltwater to be carried inland, as does the deepening of existing channels for navigation purposes. [ 2 ] [ 8 ] In Sabine Lake Estuary in the Gulf of Mexico, large-scale waterways have allowed saltwater to move into the lake, and upstream into the rivers feeding the lake. Additionally, channel dredging in the surrounding wetlands to facilitate oil and gas drilling has caused land subsidence , further promoting inland saltwater movement. [ 9 ]
Drainage networks constructed to drain flat coastal areas can lead to intrusion by lowering the freshwater table, reducing the water pressure exerted by the freshwater column. Saltwater intrusion in southeast Florida has occurred largely as a result of drainage canals built between 1903 into the 1980s to drain the Everglades for agricultural and urban development. The main cause of intrusion was the lowering of the water table, though the canals also conveyed seawater inland until the construction of water control gates. [ 6 ]
The seawater intrusion (SWI) into rivers can lead to many negative consequences, especially on agricultural activities and live ecosystems in upstream areas of rivers. There are many solutions developed to prevent or reduce the negative effects of Seawater intrusion. One of the sustainable solutions for rivers is using air bubble curtains that can completely solve SWI issues in rivers. [ 10 ]
Many coastal communities around the United States are experiencing saltwater contamination of water supply wells, and this problem has been seen for decades. [ 11 ] Many Mediterranean coastal aquifers suffer for seawater intrusion effects. [ 12 ] [ 13 ] The consequences of saltwater intrusion for supply wells vary widely, depending on extent of the intrusion, the intended use of the water, and whether the salinity exceeds standards for the intended use. [ 2 ] [ 14 ] In some areas such as Washington State, intrusion only reaches portions of the aquifer, affecting only certain water supply wells. Other aquifers have faced more widespread salinity contamination, significantly affecting groundwater supplies for the region. For instance, in Cape May, New Jersey , where groundwater extraction has lowered water tables by up to 30 meters, saltwater intrusion has caused closure of over 120 water supply wells since the 1940s. [ 6 ]
The first physical formulations of saltwater intrusion were made by Willem Badon-Ghijben [ pt ] in 1888 and 1889 as well as Alexander Herzberg [ de ] in 1901, thus called the Ghyben–Herzberg relation. [ 15 ] They derived analytical solutions to approximate the intrusion behavior, which are based on a number of assumptions that do not hold in all field cases.
In the equation,
z = ρ f ( ρ s − ρ f ) h {\displaystyle z={\frac {\rho _{f}}{(\rho _{s}-\rho _{f})}}h}
the thickness of the freshwater zone above sea level is represented as h {\displaystyle h} and that below sea level is represented as z {\displaystyle z} . The two thicknesses h {\displaystyle h} and z {\displaystyle z} , are related by ρ f {\displaystyle \rho _{f}} and ρ s {\displaystyle \rho _{s}} where ρ f {\displaystyle \rho _{f}} is the density of freshwater and ρ s {\displaystyle \rho _{s}} is the density of saltwater. Freshwater has a density of about 1.000 grams per cubic centimeter (g/cm 3 ) at 20 °C, whereas that of seawater is about 1.025 g/cm 3 . The equation can be simplified to
z = 40 h {\displaystyle z\ =40h} . [ 2 ]
The Ghyben–Herzberg ratio states that, for every meter of fresh water in an unconfined aquifer above sea level, there will be forty meters of fresh water in the aquifer below sea level.
In the 20th century the vastly increased computing power available allowed the use of numerical methods (usually finite differences or finite elements ) that need fewer assumptions and can be applied more generally. [ 16 ]
Modeling of saltwater intrusion is considered difficult. Some typical difficulties that arise are:
Saltwater is also an issue where a lock separates saltwater from freshwater (for example the Hiram M. Chittenden Locks in Washington). In this case a collection basin was built from which the saltwater can be pumped back to the sea. Some of the intruding saltwater is also pumped to the fish ladder to make it more attractive to migrating fish . [ 17 ]
As groundwater salinization becomes a relevant problem, more complex initiatives should be applied from local technical and engineering solutions to rules or regulatory instruments for whole aquifers or regions. [ 18 ] | https://en.wikipedia.org/wiki/Saltwater_intrusion |
The State of California enforces several methodologies through technical innovation and scientific approach to combat saltwater intrusion in areas vulnerable to saltwater intrusion. Seawater intrusion is either caused by groundwater extraction or increased in sea level. For every 1-foot of freshwater depression (0.30 m), sea-salty waters rises 40 feet (12 m) as the cone of depression forms. [ 1 ] Salinization of groundwater is one of the main water pollution ever produced by mankind or from natural processes. It degrades water quality to the point it passes acceptable drink water and irrigation standards. [ 2 ]
Understanding the extent and rate of saltwater intrusion are key elements for sustainable water management. Ineffective management means low water quality for urban sectors and agriculture. Effective management strategies include monitoring seawater intrusion in areas prone to saltwater intrusion. Common approach for monitoring seawater intrusion include measuring groundwater level, hydrograph analysis, water quality sampling and geophysical logging. These procedures provide discrete and tangible information for early-warning signs regarding saltwater intrusion adjacent to lands and groundwater aquifers. Airborne electromagnetic measurement is used by helicopters to map out electrical resistivity. This method can provide useful information concerning water quality over 100 miles (160 km) in a day by penetrating through sea surfaces to a depth of 1,500 feet (460 m). Using airborne geophysical measurement yields useful data for interpretation and hydrological information. [ 3 ]
Groundwater basin in Los Angeles County is considered as a vital resource both for agricultures and residential areas. For more than 40 years, Los Angeles County have managed to protect local groundwater basins from seawater intrusion. By injecting freshwater along coastal regions, Los Angeles County tends to create hydraulic gradients between freshwater and saltwater. This prevents saltwater to advance further inland. [ 4 ] One critical factor affecting water supply in Los Angeles is population growth. As population growth increases in Los Angeles County, saltwater intrusion tends to advance further inland into Los Angeles groundwater aquifers. This occurs due to population growth, demanding an excess amount of freshwater from groundwater pumping wells. This sets an hydrologic condition for saltwater to follow the geomorphic pressure gradient produced landward. A cone of depression develops as a result through pumping wells operation to supply water for residential areas and agriculture. To combat saltwater intrusion, Los Angeles water districts decides to construct injection wells to form an hydraulic barrier, preventing advancement of saltwater intrusion in Los Angeles aquifers. Geologists, however, continue to study and survey Los Angeles County coastline because creating this hydraulic gradients is not fully efficient. To better understand saltwater intrusion in Los Angeles County, the U.S Geological Survey partners with Water Replenishment District of Southern California and Los Angeles County Department of Public Works to conduct a geological survey through using reflection seismology . This means that seismic profiles is essential to understand how sedimentation influence saltwater intrusion. [ 5 ]
The Alamitos Barrier Project is one of the three hydraulic barriers in Los Angeles County. It was created mainly to protect groundwater supplies from seawater intrusion. It is currently operated under Los Angeles County Flood Control District and the Orange County Water District . Other joint committees include the Water Replenishment District of Southern California who is responsible for supplying water to each hydraulic barrier and then the County of Los Angeles Department of Public Works who operates the projects on a daily basis. The effects of seawater intrusion took first noticed in 1956. As a response, a coastal barrier project was later built by the Orange County Water District to combat saltwater intrusion which remains prominent and troublesome to this day. Known as Water Factory 21 , the District built in seven extraction wells located 2 miles away from the coast to intercept and send saltwater back into the sea. A series of 23 injection wells were also built further inland to create a powerful hydraulic barrier between saltwater and freshwater. The water supplies of Water Factory 21 undergo several phases before it reaches the injection wells. This man-made hydraulic processes includes air stripping , recarbonation, multi-media filtration, carbon sequestration and chlorination . 23,000 acres feet of water is produced each year to supply this amount of water into each injection wells to form effective yet inefficient hydraulic barrier. After each water droplet goes through each treatment, the injections wells distributes this vast amount of freshwater into the ocean and into the groundwater basin. Majority of this freshwater is flowed into the groundwater basin to meet consumers demands. [ 6 ]
Both the levee system and delta islands help protect freshwater hydrology and municipal water treatment facilities from saltwater intrusion. Under extreme drought conditions, the combined flow of fresh water from all of the San Joaquin river's tributaries is no longer sufficient to stem the brackish flows that come in from the bay on every tidal cycle. State officials have gone so far as to build levees across major saltwater in-flows in times of especially severe drought. [ 7 ] Saltwater intrusion is temporarily stemmed in spring months when snow melt and rain runoff increase water volumes carried by the San Joaquin and Sacramento rivers, fending off saltwater intrusion. It is expected that the issue of saltwater intrusion in this delta will get worse as climate cycles affected by climate change push California further into drought, as stream flows further decrease in summer months after snowpack support has waned. [ 8 ] Before human intervention, saltwater regularly flooded the marshes in the Delta, but the location of pumping stations providing water for agricultural and domestic use means that saltwater intrusion would be catastrophic for state's water supply. The health of the naturally formed barrier islands is critical for continued salt water exclusion, and is an active area of research. [ 9 ] [ 10 ]
In the southernmost part of the Delta, the concentration of saltwater content increases as farmers irrigate their crops for fresh produce. The agricultural drainage water is where salinization intensified through the process of irrigation. In some occasion, there may be no delta water that is left to flush out and push back saltwater content within the delta, specifically in the south Delta. This creates a localize salinity problems for water managers to address or mitigate since salinity is highly concentrated. [ 10 ]
The Suisun Marsh is one of the largest brackish water wetlands in the Sacramento-San Joaquin Delta. This aquatic habitat is where freshwater and saltwater meets. Here lies 230 miles of levees protecting the Suisun Marsh. The Delta salinity greatly influenced the overall health of the Suisun Marsh. This include the ecosystem in this area, encompassing living plants and neighboring species. The State Water Project's Suisun Marsh Salinity Control Gates manages tidal flows to limit saltwater intrusion from salty tidal flows. The California's Department of Water Resources built this tidal-flow control gate to limit high saline first introduced from Grizzly Bay and through the Montezuma Slough. [ 11 ] | https://en.wikipedia.org/wiki/Saltwater_intrusion_in_California |
Salva congruitate [ 1 ] is a Latin scholastic term in logic , which means "without becoming ill-formed", [ 2 ] salva meaning rescue , salvation , welfare and congruitate meaning combine , coincide , agree . Salva Congruitate is used in logic to mean that two terms may be substituted for each other while preserving grammaticality in all contexts. [ 3 ] [ 4 ]
Timothy C. Potts describes salva congruitate as a form of replacement in the context of meaning. It is a replacement which preserves semantic coherence and should be distinguished from a replacement which preserves syntactic coherence but may yield an expression to which no meaning has been given. This means that supposing an original expression is meaningful, the new expression obtained by the replacement will also be meaningful, though it will not necessarily have the same meaning as the original one, nor, if the expression in question happens to be a proposition , will the replacement necessarily preserve the truth value of the original. [ 5 ]
Bob Hale explains salva congruitate , as applied to singular terms, as substantival expressions in natural language, which are able to replace singular terms without destructive effect on the grammar of a sentence. [ 6 ] Thus the singular term 'Bob' may be replaced by the definite description 'the first man to swim the English Channel' salva congruitate . Such replacement may shift both meaning and reference, and so, if made in the context of a sentence, may cause a change in truth-value. Thus terms which may be interchanged salva congruitate may not be interchangeable salva veritate (preserving truth). More generally, expressions of any type are interchangeable salva congruitate if and only if they can replace one another preserving grammaticality or well-formedness. | https://en.wikipedia.org/wiki/Salva_congruitate |
The Salvinia effect describes the permanent stabilization of an air layer upon a hierarchically structured surface submerged in water. Based on biological models (e.g. the floating ferns Salvinia , backswimmer Notonecta ), biomimetic Salvinia-surfaces are used as drag reducing coatings (up to 30% reduction were previously measured on the first prototypes. [ 1 ] [ 2 ] When applied to a ship hull, the coating would allow the boat to float on an air-layer, reducing energy consumption and emissions. Such surfaces require an extremely water repellent super-hydrophobic surface and an elastic hairy structure in the millimeter range to entrap air while submerged. The Salvinia effect was discovered by the biologist and botanist Wilhelm Barthlott (University of Bonn) and his colleagues and has been investigated on several plants and animals since 2002. Publications and patents were published between 2006 and 2016. [ 3 ] The best biological models are the floating ferns ( Salvinia) with highly sophisticated hierarchically structured hairy surfaces, [ 4 ] and the back swimmers (e.g. Notonecta) with a complex double structure of hairs (setae) and microvilli (microtrichia). Three of the ten known Salvinia species show a paradoxical chemical heterogeneity: hydrophilic hair tips, in addition to the super-hydrophobic plant surface, further stabilizing the air layer. [ 5 ]
Immersed in water, extremely water repellent ( super-hydrophobic ), structured surfaces trap air between the structures and this air-layer is maintained for a period of time. A silvery shine, due to the reflection of light at the interface of air and water, is visible on the submerged surfaces.
Long lasting air layers also occur in aquatic arthropods which breathe via a physical gill (plastron) e. g. the water spider ( Argyroneta ) and the saucer bug ( Aphelocheirus ) Air layers are presumably also conducive to the reduction of friction in fast moving animals under water, as is the case for the back swimmer Notonecta . [ 6 ]
The best known examples for long term air retention under water are the floating ferns of genus Salvinia . About ten species of very diverse sizes are found in lentic water in all warmer regions of the earth, one widely spread species ( S. natans ) found in temperate climates can be even found in Central Europe . The ability to retain air is presumably a survival technique for these plants. The upper side of the floating leaves is highly water repellent and possesses highly complex and species-specific very distinctive hairs. [ 4 ] Some species present multicellular free-standing hairs of 0.3–3 mm length (e. g. S. cucullata ) while on others, two hairs are connected at the tips (e.g. S. oblongifolia ). S. minima and S. natans have four free standing hairs connected at a single base. The Giant Salvinia ( S. molesta ), as well as S. auriculata , and other closely related species, display the most complex hairs: four hairs grow on a shared shaft; they are connected at their tips. These structures resemble microscopic eggbeaters and are therefore referred to as “eggbeater trichomes”. The entire leaf surface, including the hairs, is covered with nanoscale wax crystals which are the reason for the water repellent properties of the surfaces. These leaf surfaces are therefore a classical example of a “hierarchical structuring“. [ 4 ]
The egg-beater hairs of Salvinia molesta and closely related species (e.g. S. auriculata ) show an additional remarkable property. The four cells at the tip of each hair (the anchor cells), [ 3 ] as opposed to the rest of the hair, are free of wax and therefore hydrophilic ; in effect, wettable islands surrounded by a super-hydrophobic surface. This chemical heterogeneity, [ 5 ] the Salvinia paradox, enables a pinning of the air water interface to the plant and increases the pressure and longtime stability of the air layer. [ 5 ] [ 7 ]
The air retaining surface of the floating fern does not lead to a reduction in friction. The ecological extremely adaptable Giant Salvinia (S. molesta) is one of the most important invasive plants in all tropical and subtropical regions of the earth and is the cause of economic as well as ecological problems. [ 8 ] Its growth rate might be the highest of all vascular plants. In the tropics and under optimal conditions, S. molesta can double its biomass within four days. The Salvinia effect, described here, most likely plays an essential role in its ecological success; the multilayered floating plant mats presumably maintain their function of gas exchange within the air-layer.
The Salvinia effect defines surfaces which are able to permanently keep relatively thick air layers as a result of their hydrophobic chemistry, in combination with a complex architecture [ 9 ] in nano- and microscopic dimensions.
This phenomenon was discovered during a systematic research on aquatic plants and animals by Wilhelm Barthlott and his colleagues at the University of Bonn between 2002 and 2007. [ 10 ] Five criteria have been defined, [ 11 ] they enable the existence of stable air layers under water and as of 2009 define the Salvinia effect: [ 12 ] (1) hydrophobic surfaces chemistry in combination with (2) nanoscalic structures generate superhydrophobicity, (3) microscopic hierarchical structures ranging from a few mirco- to several millimeters with (4) undercuts and (5) elastic properties. Elasticity appears to be important for the compression of the air-layer in dynamic hydrostatic conditions. [ 13 ] An additional optimizing criterion is the chemical heterogeneity of the hydrophilic tips (Salvinia Paradox [ 4 ] [ 6 ] ). This is a prime example of a hierarchical structuring on several levels. [ 12 ]
In plants and animals, air retaining salvinia effect surfaces are always fragmented in small compartments with a length of 0.5 to 8 cm and the borders are sealed against loss of air by particular microstructures. [ 1 ] [ 3 ] [ 14 ] Compartments with sealed edges are also important for technical applications.
The working principle is illustrated in for the Giant Salvinia. [ 4 ] The leaves of S. molesta are capable of keeping an air layer on its surfaces for a long time when submerged in water. If a leaf is pulled under water, the leaf surface shows a silvery shine. The distinctive feature of S. molesta lies in the long term stability. While the air layer on most hydrophobic surfaces vanishes shortly after submerging, S. molesta is able to stabilize the air for several days to several weeks. The time span is thereby just limited by the lifetime of the leaf.
The high stability is a consequence of a seemingly paradoxical combination of a superhydrophobic (extremely water repellent) surface with hydrophilic (water attractive) patches on the tips of the structures.
When submerged under water, no water can penetrate the room between the hairs due to the hydrophobic character of the surfaces. However, the water is pinned to the tip of each hair by the four wax free (hydrophilic) end cells. This fixation results in a stabilization of the air layer under water. The principle is shown in the figure.
Two submerged, air retaining surfaces are schematically shown: on the left hand side: a hydrophobic surface. On the right hand side: a hydrophobic surface with hydrophilic tips.
If negative pressure is applied, a bubble is quickly formed on the purely hydrophobic surfaces (left) stretching over several structures. With increasing negative pressure the bubble grows and can detach from the surface. The air bubble rises to the surface and the air layer decreases until it vanishes completely.
In case of the surface with hydrophilic anchor cells (right) the water is pinned to the tips of every structure by the hydrophilic patch on top. These linkages allow the formation of a bubble stretching over several structures; bubble release is suppressed because several links have to be broken first. This results in a higher energy input for the bubble formation. Therefore, an increased negative pressure is needed to form a bubble able to detach from the surface and rise upwards.
Underwater air retaining surfaces are of great interest for technical applications. If a transfer of the effect to a technical surface is successful, ship hulls could be coated with this surface to reduce friction between ship and water resulting in less fuel consumption, fuel costs and reduction of its negative environmental impact (antifouling effect by the air layer). [ 15 ] In 2007 first test boats already achieved a ten percent friction reduction [ 9 ] and the principle was subsequently patented. [ 16 ] By now scientists assume a friction reduction of over 30%. [ 17 ]
The underlying principle is schematically shown in a figure. Two flow profiles of laminar flow in water over a solid surface and water flowing over an air retaining surface are compared here.
If water flows over a smooth solid surface, the velocity at the surface is zero due to the friction between water and surface molecules. If an air layer is situated between the solid surface and the water the velocity is higher than zero. The lower viscosity of air (55 times lower than the viscosity of water) reduces the transmission of friction forces by the same factor.
Researchers are currently working on the development of a biomimetic , permanently air retaining surface modeled on S. molesta [ 18 ] to reduce friction on ships. Salvinia-Effect surfaces have been proven to quickly and efficiently adsorb oil and can be used for oil-water separation applications [ 19 ] | https://en.wikipedia.org/wiki/Salvinia_effect |
The salvo combat model provides a mathematical representation of anti-ship missile battles between modern warships . It was developed by Wayne Hughes at the U.S. Naval Postgraduate School in Monterey, California, and published in 1995. [ 1 ] The salvo model describes the basic elements of modern missile combat in a very simple manner. This is similar to how Lanchester's square law provides a simple model of modern gun combat. [ 2 ]
Suppose that two naval forces, Red and Blue, are engaging each other in combat. The battle begins with Red firing a salvo of missiles at Blue. The Blue ships try to shoot down those incoming missiles. Simultaneously, Blue launches a salvo that Red tries to intercept.
This exchange of missile fire can be modeled as follows. Let symbol A represent the number of combat units (warships or other weapon platforms) in the Red force at the beginning of the battle. Each one has offensive firepower α , which is the number of offensive missiles accurately fired per salvo at the enemy. Each one also has defensive firepower y , which is the number of incoming enemy missiles intercepted per salvo by its active defenses. Each ship has staying power w , which is the number of enemy missile hits required to put it out of action. Equivalently, one could say that each attacking missile can cause damage equal to a fraction u=1/w of a Red ship.
The Blue force is represented in a similar manner. Blue has B units, each with offensive firepower β , defensive firepower z , and staying power x . Each missile that hits will cause damage v=1/x .
The salvo combat model calculates the number of ships lost on each side using the following pair of equations. Here, ΔA represents the change in the number of Red's ships from one salvo, while ΔB represents the change in the number of Blue ships.
Each equation starts by calculating the total number of offensive missiles being launched by the attacker. It then subtracts the total number of interceptions by the defender. The number of remaining (non-intercepted) offensive missiles is multiplied by the amount of damage caused per missile to get the total amount of damage. If there are more defensive interceptions than offensive missiles, then the total damage is zero; it cannot be negative.
These equations assume that each side is using aimed fire; that is, a force knows the location of its target and can aim its missiles at it. If however a force knows only the approximate location of its target (e.g., somewhere within a fog bank), then it may spread its fire across a wide area, with the hope that at least some of its missiles will find the target. A different version of the salvo equations is required for such area fire. [ 3 ]
Mathematically, the salvo equations can be thought of as difference equations or recurrence relations . They are also an example of operations research .
A stochastic (or probabilistic) version of the model also exists. [ 4 ] In this version, the ship parameters listed above are random variables instead of constants. This means that the result of each salvo also varies randomly. The stochastic model can be incorporated into a computer spreadsheet and used instead of the Monte Carlo method of computer simulation. [ 5 ] An alternative version of this model exists for situations where one side attacks first, and then the survivors (if any) on the other side counter-attack, [ 6 ] such as at the Battle of Midway .
The salvo equations are related to Lanchester's Square Law equations, with two main differences.
First, the basic salvo equations form a discrete time model, whereas Lanchester's original equations form a continuous time model. Cruise missiles typically are fired in relatively small quantities. Each one has a high probability of hitting its target, if not intercepted, and carries a relatively powerful warhead. Therefore, it makes sense to model them as a discrete pulse (or salvo) of firepower.
By comparison, bullets or shells in a gun battle are typically fired in large quantities. Each round has a relatively low chance of hitting its target, and does a relatively small amount of damage. Therefore, it makes sense to model them as a small but continuous stream of firepower.
Second, the salvo equations include defensive firepower, whereas Lanchester's original equations include only offensive firepower. Cruise missiles can be intercepted (shot down) by active defenses, such as surface-to-air missiles and anti-aircraft guns. By comparison, it is generally not practical to intercept bullets and shells during a gun battle.
The salvo model primarily represents naval missile battles, such as those that occurred during the Falklands War . Offensive firepower represents anti-ship cruise missiles such as the Harpoon , the Exocet and the Styx . Defensive firepower represents air defense missiles such as the Standard , as well as anti-aircraft guns such as the Phalanx . However, one can adapt the model to other kinds of battles having similar characteristics.
For example, some authors have used it study World War II battles between aircraft carriers, [ 7 ] such as the Battle of the Coral Sea . [ 8 ] In this case, the offensive firepower consists of dive bombers and torpedo bombers. The defensive firepower consists of fighter aircraft that try to intercept those bombers.
The model could instead describe battles where torpedoes are the main form of offensive firepower, such as in the Battle of Savo Island . In this case, the defensive firepower would be zero, since so far there is no effective way to intercept torpedoes.
A simplified version of the model was used to study alternative outcomes of the Charge of the Light Brigade by British cavalry against Russian cannon in 1854. [ 9 ] The model has also been modified to represent tactical ballistic missile defense . This variant was used to analyze the performance of the Iron Dome missile defense system during 2012's Operation Pillar of Defense . [ 10 ]
The salvo combat model can help with research on a variety of issues in naval warfare. [ 11 ] For example, one study examined the value of having accurate information about an enemy fleet. [ 12 ] Another study examined how many missiles would be required to achieve a desired probability of success when attacking several targets at once. [ 13 ] Researchers have also analyzed the mathematical properties of the model itself. [ 14 ]
The initial goal of such research is to get a better understanding of how the model works. A more important objective is to see what the model might suggest about the behavior of real missile battles. This could help with the development of better modern naval tactics for attacking with and defending against such missiles. | https://en.wikipedia.org/wiki/Salvo_combat_model |
Samantha Joanne Payne MBE is an English entrepreneur. The co-founder of Open Bionics , a bionics company developing affordable prosthetics for children, [ 1 ] Payne has won a number of international awards for her work. These include the MIT Technology Review 'Innovators under 35' in 2018, [ 2 ] James Dyson gong for innovative engineering [ 1 ] and Wired Innovation Fellow in 2016. [ 3 ] In the Queen's Birthday Honours list 2020, Payne was awarded an MBE , for her work making bionic technology more accessible. [ 4 ]
Born and raised in Knowle West , outside of Bristol, England. [ 5 ] Payne is a graduate of Whitworth University and has a Bachelor of Arts/Science. [ 6 ]
She worked as a journalist, specialising in technology before becoming a co-founder of Open Bionics. [ 7 ] In 2013, whilst working as a journalist, Payne interviewed Joel Gibbard, who was a robotics graduate at the time. [ 1 ] Gibbard and Payne later became business partners and co-founders of Open Bionics. [ 1 ]
Payne and Gibbard founded Open Bionics in 2014. [ 1 ] The start-up was initially based at the Technology Business Incubator at Bristol Robotics Laboratory . [ 8 ] The aim of the company was to develop "affordable, assistive devices that enhance the human body." [ 4 ]
Open Bionics has partnered with Disney to make prosthetics based on Disney characters for children. [ 4 ]
Her work at Open Bionics has been featured in The Guardian [ 1 ] and Daily Mirror . [ 9 ]
Open Bionics uses 3D scanning to take the initial prosthetic fitting and 3D printing to improve the prosthetic design. [ 1 ] These innovations significantly reduce the build-time and the material costs for a personalised hand, making prosthetics more affordable for amputees. [ 1 ] Payne estimates that, if bought from private providers, bionic hands with multi-grip functionality cost up to £60,000, compared to £5,000 from Open Bionics. [ 1 ]
In 2015, Payne was shortlisted for Women in Business 'Young Entrepreneur of The Year' award. [ 8 ] In 2018, Payne featured on the Forbes 30 Under 30 list in the Sciences and Healthcare category. [ 10 ]
This article about an engineer, inventor or industrial designer from the United Kingdom or its predecessor states is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Samantha_Payne |
Samarium(II) bromide is an inorganic compound with the chemical formula SmBr 2 . [ 6 ] It is a brown solid that is insoluble in most solvents but degrades readily in air. [ 4 ]
In the gas phase, SmBr 2 is a bent molecule with Sm–Br distance 274.5 pm and bond angle 131±6°. [ 7 ]
Samarium(II) bromide was first synthesized in 1934 by P. W. Selwood , when he reduced samarium tribromide (SmBr 3 ) with hydrogen (H 2 ). Kagan also synthesized it by converting samarium(III) oxide (Sm 2 O 3 ) to SmBr 3 and then reducing with a lithium dispersion in THF . Robert A. Flowers synthesized it by adding two equivalent of lithium bromide (LiBr) to samarium diiodide (SmI 2 ) in tetrahydrofuran . Namy managed to synthesize it by mixing tetrabromoethane (C 2 H 2 Br 4 ) with samarium metal, and Hilmerson found that heating the tetrabromoethane or samarium greatly improved the production of samarium(II) bromide. [ 8 ]
Samarium(II) bromide has reducing properties reminiscent of the more commonly used samarium diiodide . [ 9 ] It is an effective for pinacol homocouplings of aldehydes , ketones , and cross-coupling carbonyl compounds. Reports have shown that samarium(II) bromide is capable of selectively reducing ketones if it is in the presence of an alkyl halide . [ 8 ]
Samarium(II) bromide forms soluble adducts with hexamethylphosphoramide . This species reduces imines to amines and alkyl chlorides to hydrocarbons . [ 10 ] For example, SmBr 2 (hmpa) x converts cyclohexyl chloride to cyclohexane . [ 11 ]
Samarium(II) bromide will reduce ketones in tetrahydrofuran if an activator is absent. [ 12 ] | https://en.wikipedia.org/wiki/Samarium(II)_bromide |
Samarium(II) iodide is an inorganic compound with the formula SmI 2 . When employed as a solution for organic synthesis , it is known as Kagan 's reagent . SmI 2 is a green solid and forms a dark blue solution in THF . [ 1 ] It is a strong one-electron reducing agent that is used in organic synthesis .
In solid samarium(II) iodide, the metal centers are seven-coordinate with a face-capped octahedral geometry . [ 2 ]
In its ether adducts , samarium remains heptacoordinate with five ether and two terminal iodide ligands. [ 3 ]
Samarium iodide is easily prepared in nearly quantitative yields from samarium metal and either diiodomethane or 1,2-diiodoethane . [ 4 ] When prepared in this way, its solutions is most often used without purification of the inorganic reagent.
Solid, solvent-free SmI 2 forms by high temperature decomposition of samarium(III) iodide (SmI 3 ). [ 5 ] [ 6 ] [ 7 ]
Samarium(II) iodide is a powerful reducing agent – for example it rapidly reduces water to hydrogen . [ 2 ] It is available commercially as a dark blue 0.1 M solution in THF. Although used typically in superstoichiometric amounts, catalytic applications have been described. [ 8 ]
Samarium(II) iodide is a reagent for carbon-carbon bond formation, for example in a Barbier reaction (similar to the Grignard reaction ) between a ketone and an alkyl iodide to form a tertiary alcohol : [ 9 ]
Typical reaction conditions use SmI 2 in THF in the presence of catalytic NiI 2 .
Esters react similarly (adding two R groups), but aldehydes give by-products. The reaction is convenient in that it is often very rapid (5 minutes or less in the cold). Although samarium(II) iodide is considered a powerful single-electron reducing agent, it does display remarkable chemoselectivity among functional groups. For example, sulfones and sulfoxides can be reduced to the corresponding sulfide in the presence of a variety of carbonyl -containing functionalities (such as esters , ketones , amides , aldehydes , etc.). This is presumably due to the considerably slower reaction with carbonyls as compared to sulfones and sulfoxides . Furthermore, hydrodehalogenation of halogenated hydrocarbons to the corresponding hydrocarbon compound can be achieved using samarium(II) iodide. Also, it can be monitored by the color change that occurs as the dark blue color of SmI 2 in THF discharges to a light yellow once the reaction has occurred. The picture shows the dark colour disappearing immediately upon contact with the Barbier reaction mixture.
Work-up is with dilute hydrochloric acid , and the samarium is removed as aqueous Sm 3+ .
Carbonyl compounds can also be coupled with simple alkenes to form five, six or eight membered rings. [ 10 ]
Tosyl groups can be removed from N -tosylamides almost instantaneously, using SmI 2 in conjunction with distilled water and an amine base. The reaction is even effective for deprotection of sensitive substrates such as aziridines : [ 11 ]
In the Markó-Lam deoxygenation , an alcohol could be almost instantaneously deoxygenated by reducing their toluate ester in presence of SmI 2 .
SmI 2 can also be used in the transannulation of bicyclic molecules . An example is the SmI 2 induced ketone - alkene cyclization of 5-methylenecyclooctanone which proceeds through a ketyl intermediate:
The applications of SmI 2 have been reviewed. [ 12 ] [ 13 ] [ 14 ] The book Organic Synthesis Using Samarium Diiodide , published in 2009, gives a detailed overview of reactions mediated by SmI 2 . [ 15 ] | https://en.wikipedia.org/wiki/Samarium(II)_iodide |
Samarium(III) arsenide is a binary inorganic compound of samarium and arsenic with the chemical formula SmAs . [ 1 ] [ 2 ]
Samarium arsenide can be synthesised by heating of pure substances in vacuum:
Samarium arsenide forms crystals of a cubic system , [ 3 ] space group Fm3m , cell parameters a = 0.5921 nm, Z = 4, of NaCl -structure. [ 4 ] [ 5 ]
The compound melts congruently at 2257 °C.
SmAs is used as a semiconductor and in photo optic applications. [ 6 ] | https://en.wikipedia.org/wiki/Samarium(III)_arsenide |
Samarium(III) iodide is an inorganic compound , a salt of samarium and hydroiodic acid with the chemical formula SmI 3 . [ 1 ] [ 2 ]
Samarium(III) iodide is prepared by the reaction of metallic samarium and iodine : [ 3 ]
Samarium(III) iodide is a yellow powder that is unstable in air and decomposes in water ( hydrolysis ). [ 1 ] When heated with metallic samarium, it forms samarium diiodide : [ 4 ]
Reduction by hydrogen also affords samarium diiodide upon heating:
The compound is commercially available and used in organic reactions as a catalyst . [ 1 ] | https://en.wikipedia.org/wiki/Samarium(III)_iodide |
Samarium–cobalt (SmCo) magnets belong to the category of rare-earth magnets and are composed of samarium (Sm), a rare-earth element , and cobalt (Co), a transition metal . They are among the strongest permanent magnets.
They were developed in the early 1960s based on work done by Karl Strnat at Wright-Patterson Air Force Base and Alden Ray at the University of Dayton . In particular, Strnat and Ray developed the first formulation of SmCo 5 . [ 1 ] [ 2 ]
Samarium–Cobalt magnets are generally ranked similarly in strength to neodymium magnets , [ 3 ] but have higher temperature ratings and higher coercivity .
Some attributes of samarium-cobalts are:
Samarium–Cobalt magnets are available in two "series", namely SmCo 5 magnets and Sm 2 Co 17 magnets. [ 7 ] [ 8 ]
These samarium–cobalt magnet alloys (generally written as SmCo 5 , or SmCo Series 1:5) have one atom of rare-earth samarium per five atoms of cobalt. By weight, this magnet alloy will typically contain 36% samarium with the balance cobalt . [ 9 ] The energy products of these samarium–cobalt alloys range from 16 MG·Oe to 25 MG·Oe, that is, approx. 128–200 kJ/m 3 . These samarium–cobalt magnets generally have a reversible temperature coefficient of -0.05%/°C. Saturation magnetization can be achieved with a moderate magnetizing field. This series of magnet is easier to calibrate to a specific magnetic field than the SmCo 2:17 series magnets.
In the presence of a moderately strong magnetic field, unmagnetized magnets of this series will try to align their orientation axis to the magnetic field, thus becoming slightly magnetized. This can be an issue if postprocessing requires that the magnet be plated or coated. The slight field that the magnet picks up can attract debris during the plating or coating process, causing coating failure or a mechanically out-of-tolerance condition.
B r drifts with temperature and it is one of the important characteristics of magnet performance. Some applications, such as inertial gyroscopes and travelling wave tubes (TWTs), need to have constant field over a wide temperature range. The reversible temperature coefficient (RTC) of B r is defined as
To address these requirements, temperature compensated magnets were developed in the late 1970s. For conventional SmCo magnets, B r decreases as temperature increases. Conversely, for GdCo magnets, B r increases as temperature increases within certain temperature ranges. By combining samarium and gadolinium in the alloy, the temperature coefficient can be reduced to nearly zero.
SmCo 5 magnets have a very high coercivity (coercive force); that is, they are not easily demagnetized. They are fabricated by packing wide-grain lone-domain magnetic powders. The crystal system is hexagonal with space group P6/mmm. All of the magnetic domains are aligned with the easy axis direction, which is the one perpendicular to the hexagonal base in the lattice of the crystal. In this case, all of the domain walls are at 180 degrees. When there are no impurities, the reversal process of the bulk magnet is equivalent to lone-domain motes, where coherent rotation is the dominant mechanism. However, due to the imperfection of fabricating, impurities may be introduced in the magnets, which form nuclei. In this case, because the impurities may have lower anisotropy or misaligned easy axes, their directions of magnetization are easier to spin, which breaks the 180° domain wall configuration. In such materials, the coercivity is controlled by nucleation. To obtain much coercivity, impurity control is critical in the fabrication process.
These alloys (written as Sm 2 Co 17 , or SmCo Series 2:17) are age-hardened with a composition of two atoms of rare-earth samarium per 13–17 atoms of transition metals (TM). The arrangement of the atoms is rhombohedral in the space group R-3m. The TM content is rich in cobalt, but contains other elements such as iron and copper. Other elements like zirconium , hafnium , and such may be added in small quantities to achieve better heat treatment response. By weight, the alloy will generally contain 25% of samarium. The maximum energy products of these alloys range from 20 to 32 MGOe, what is about 160-260 kJ/m 3 . These alloys have the best reversible temperature coefficient of all rare-earth alloys, typically being -0.03%/°C. The "second generation" materials can also be used at higher temperatures. [ 10 ]
In Sm 2 Co 17 magnets, the coercivity mechanism is based on domain wall pinning . Impurities inside the magnets impede the domain wall motion and thereby resist the magnetization reversal process. To increase the coercivity, impurities are intentionally added during the fabrication process.
Samarium–cobalt alloys are typically machined in the unmagnetized state. Samarium–cobalt should be ground using a wet grinding process (water-based coolants) and a diamond grinding wheel. The same type of process is required if drilling holes or other features that are confined. The grinding waste produced must not be allowed to completely dry as samarium–cobalt has a low ignition point. A small spark, such as that produced with static electricity, can easily initiate combustion. [ 11 ] The resulting fire produced can be extremely hot and difficult to control. [ original research? ]
The reduction/melt method and reduction/diffusion method are used to manufacture samarium–cobalt magnets. The reduction/melt method will be described since it is used for both SmCo 5 and Sm 2 Co 17 production. The raw materials are melted in an induction furnace or arc furnace filled with argon gas. The mixture is cast into a mold and cooled with water to form an ingot. The production of the two phases is not the same, this can be understood by looking at the phase diagram. in fact the 1:5 phase is not stable at room temperature. [ 12 ] Typically it is possible to keep the 1:5 phase with a fast quenching after an annealing process.
The ingot is pulverized and the particles are further milled to further reduce the particle size. This process is important to because the control of the grain size is fundamental for the control of the coercive field. [ 13 ] The resulting powder is pressed in a die of desired shape, in a magnetic field to orient the magnetic field of the particles. Sintering is applied at a temperature of 1100˚C–1250˚C, followed by solution treatment at 1100˚C–1200˚C and tempering is finally performed on the magnet at about 700˚C–900˚C. [ 14 ] [ 15 ] It then is ground and further magnetized to increase its magnetic properties. The finished product is tested, inspected and packed. [ citation needed ]
Samarium can be substituted by a portion of other rare-earth elements including praseodymium , cerium , and gadolinium , the problem is the effects that this substitutions can have on the Curie temperature and on the coercive field. The cobalt can be substituted with a portion of other transition metals including iron , copper , and zirconium . [ 16 ] [ 17 ]
Fender used one of designer Bill Lawrence 's Samarium Cobalt Noiseless series of electric guitar pickups in Fender's Vintage Hot Rod '57 Stratocaster . [ 18 ] These pickups were used in American Deluxe Series Guitars and Basses from 2004 until early 2010. [ 19 ]
Samarium-cobalt (SmCo) magnets are used in aerospace and defense due to their exceptional magnetic properties. [ 20 ] They are utilized in high-performance motors and actuators , precision sensors and gyroscopes , and satellite systems where stability and reliability are essential. [ 21 ] They are also used in medical technologies, including MRI machines, pacemakers , and medical pumps. [ 22 ]
In the mid-1980s some expensive headphones such as the Ross RE-278 used samarium–cobalt "Super Magnet" transducers.
Other uses include: | https://en.wikipedia.org/wiki/Samarium–cobalt_magnet |
Sameh Fahmi (born 14 August 1949) is an Egyptian engineer and politician who served as oil minister of Egypt for 12 years from 1999 to 2011.
Fahmi was born in Cairo on 14 August 1949. [ 1 ] He has a twin brother, Hadi Fahmi. [ 1 ] Sameh Fahmi holds a bachelor's degree in chemical engineering, which he received from Cairo University in June 1973. [ 1 ]
After graduation, Fahmi began to work at the Egyptian General Petroleum Corporation (EGPC) . [ 1 ] In May 1993, he became a board member and vice head of the EGPC in charge of planning and projects. [ 1 ] In January 1997, he was appointed CEO and vice chairman of the Midor oil refining venture near Alexandria. [ 1 ] In 1997, he began to serve as a board member of the Petroleum and Mining Chamber and of the Federation of Egyptian Industries. [ 1 ] In August 1998, he was named a board member of the Alexandria Company for Petroleum Maintenance. [ 1 ] He joined the National Democratic Party and became a member of its policy secretariat. [ 2 ]
Fahmi was appointed oil minister to the cabinet led by the Prime Minister Atef Ebeid on 5 October 1999, replacing Hamdi Al Banbi in the post. [ 1 ] [ 3 ] Fahmi was also named the chairman of the Egyptian Gas Holding Company. [ 4 ] He was instrumental in the establishment of the Egyptian holding company for petrochemicals (ECHEM) in 2002. [ 5 ] A 15-year natural gas deal was signed by him and Israeli national infrastructure minister Benjamin Ben-Eliezer in July 2005. [ 6 ] [ 7 ] In December 2010, he was appointed president of the Gas Exporting Countries Forum . [ 8 ] Although he retained his post in the cabinet led by Ahmed Shafik in the January 2011 reshuffle, [ 9 ] he resigned from office due to the complaints of oil workers on 16 February 2011. [ 10 ] His term ended on 21 February 2011, [ 11 ] [ 12 ] and he was replaced by Mahmoud Latif Amer as oil minister. [ 13 ] [ 14 ]
After leaving office, Fahmi was investigated because of alleged wrongdoing. [ 14 ] In April 2011, it was announced by the public prosecutor that he would be tried in relation to the charges related to a natural gas deal with Israel. [ 15 ] [ 16 ] He was arrested and held in custody on 21 April 2011. [ 17 ] [ 18 ] Fahmi was sentenced to 15 years in prison in June 2012 due to his alleged role in selling and exporting natural gas to Israel in 2005 at lower prices than market rates. [ 19 ] [ 20 ] He along with other officials was also fined about $2.3 billion. [ 16 ]
In mid-March 2013, the court of cassation decided that Fahmi should be retried over the Egypt-Israel gas case. [ 21 ] On 28 March 2013, he was released from prison since he stayed in prison longer than the maximum 18 months allowed for pre-trial detention. [ 22 ] Specifically, he was jailed for 23 months. [ 21 ] | https://en.wikipedia.org/wiki/Sameh_Fahmi |
In general, a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing(s). [ 1 ] The things could be countable objects such as individual items available as units for sale, or an uncountable material. Even though the word "sample" implies a smaller quantity taken from a larger amount, sometimes full biological or mineralogical specimens are called samples if they are taken for analysis, testing, or investigation like other samples. They are also considered samples in the sense that even whole specimens are "samples" of the full population of many individual organisms. [ 2 ] The act of obtaining a sample is called "sampling" [ 3 ] and can be performed manually by a person or by automatic process. Samples of material can be taken or provided for testing, analysis , investigation, quality control , demonstration, or trial use. Sometimes, sampling may be performed continuously. [ 4 ] [ 5 ]
In science , a representative liquid sample taken from a larger amount of liquid is sometimes called an aliquot [ 6 ] or aliquot part where the sample is an exact divisor of the whole. For example, 10mL would be an aliquot part of a 100mL sample.
The material may be solid , liquid , gas , a material of some intermediate characteristics such as gel or sputum , tissue , organism , or a combination of these. Even if a material sample is not countable as individual items, the quantity of the sample may still be describable in terms of its volume , mass , size, or other such dimensions. A solid sample can come in one or a few discrete pieces, or it can be fragmented, granular, or powdered. [ 7 ] A section of a rod, wire, cord, sheeting, or tubing may be considered a sample. Samples which are not a solid piece are commonly kept in a container of some sort.
Where goods are sold or supplied by reference to a sample, relevant sale of goods legislation may dictate the supplier's legal obligations in ensuring that the bulk of the goods corresponds with the goods comprising the sample, for example in the UK, the Sale of Goods Act 1979 , section 15, [ 8 ] the Supply of Goods and Services Act 1982 , section 5, [ 9 ] and the Consumer Rights Act 2015 , section 13. [ 10 ] | https://en.wikipedia.org/wiki/Sample_(material) |
The Sample and Data Relationship Format ( SDRF ) is part of the MAGE-TAB standard for communicating the results
of microarray investigations, including all information required for MIAME compliance. [ 1 ]
An SDRF file is a tab-delimited file describing the relationships between samples, arrays, data, and other objects used or produced in a microarray investigation.
For simple experimental designs, constructing the SDRF file is straightforward, and even complex loop designs can be expressed in this format.
This bioinformatics-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Sample_and_Data_Relationship_Format |
A sample injector is a device used in conjunction with injecting samples into high-performance liquid chromatography (HPLC) or similar chromatography apparati.
This article related to chromatography is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Sample_injector |
In analytical chemistry , sample preparation (working-up) refers to the ways in which a sample is treated prior to its analyses. Preparation is a very important step in most analytical techniques, because the techniques are often not responsive to the analyte in its in-situ form, or the results are distorted by interfering species . Sample preparation may involve dissolution , extraction , reaction with some chemical species, pulverizing , treatment with a chelating agent (e.g. EDTA ), masking , filtering , dilution , sub-sampling or many other techniques.
Treatment is done to prepare the sample into a form ready for analysis by specified analytical equipment.
Sample preparation could involve: crushing and dissolution, chemical digestion with acid or alkali, sample extraction, sample clean up and sample pre-concentration.
This article about analytical chemistry is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Sample_preparation |
Sample preparation equipment refers to equipment used for the preparation of physical specimens for subsequent microscopy or related disciplines - including failure analysis and quality control . The equipment includes the following types of machinery:
Each of these system types incorporates a wealth of accessories and consumable items which fit the particular system for a specific application. | https://en.wikipedia.org/wiki/Sample_preparation_equipment |
In probability theory , the sample space (also called sample description space , [ 1 ] possibility space , [ 2 ] or outcome space [ 3 ] ) of an experiment or random trial is the set of all possible outcomes or results of that experiment. [ 4 ] A sample space is usually denoted using set notation , and the possible ordered outcomes, or sample points, [ 5 ] are listed as elements in the set. It is common to refer to a sample space by the labels S , Ω, or U (for " universal set "). The elements of a sample space may be numbers, words, letters, or symbols. They can also be finite , countably infinite, or uncountably infinite . [ 6 ]
A subset of the sample space is an event , denoted by E {\displaystyle E} . If the outcome of an experiment is included in E {\displaystyle E} , then event E {\displaystyle E} has occurred. [ 7 ]
For example, if the experiment is tossing a single coin, the sample space is the set { H , T } {\displaystyle \{H,T\}} , where the outcome H {\displaystyle H} means that the coin is heads and the outcome T {\displaystyle T} means that the coin is tails. [ 8 ] The possible events are E = { } {\displaystyle E=\{\}} , E = { H } {\displaystyle E=\{H\}} , E = { T } {\displaystyle E=\{T\}} , and E = { H , T } {\displaystyle E=\{H,T\}} . For tossing two coins, the sample space is { H H , H T , T H , T T } {\displaystyle \{HH,HT,TH,TT\}} , where the outcome is H H {\displaystyle HH} if both coins are heads, H T {\displaystyle HT} if the first coin is heads and the second is tails, T H {\displaystyle TH} if the first coin is tails and the second is heads, and T T {\displaystyle TT} if both coins are tails. [ 9 ] The event that at least one of the coins is heads is given by E = { H H , H T , T H } {\displaystyle E=\{HH,HT,TH\}} .
For tossing a single six-sided die one time, where the result of interest is the number of pips facing up, the sample space is { 1 , 2 , 3 , 4 , 5 , 6 } {\displaystyle \{1,2,3,4,5,6\}} . [ 10 ]
A well-defined, non-empty sample space S {\displaystyle S} is one of three components in a probabilistic model (a probability space ). The other two basic elements are a well-defined set of possible events (an event space), which is typically the power set of S {\displaystyle S} if S {\displaystyle S} is discrete or a σ-algebra on S {\displaystyle S} if it is continuous, and a probability assigned to each event (a probability measure function). [ 11 ]
A sample space can be represented visually by a rectangle, with the outcomes of the sample space denoted by points within the rectangle. The events may be represented by ovals, where the points enclosed within the oval make up the event. [ 12 ]
A set Ω {\displaystyle \Omega } with outcomes s 1 , s 2 , … , s n {\displaystyle s_{1},s_{2},\ldots ,s_{n}} (i.e. Ω = { s 1 , s 2 , … , s n } {\displaystyle \Omega =\{s_{1},s_{2},\ldots ,s_{n}\}} ) must meet some conditions in order to be a sample space: [ 13 ]
For instance, in the trial of tossing a coin, one possible sample space is Ω 1 = { H , T } {\displaystyle \Omega _{1}=\{H,T\}} , where H {\displaystyle H} is the outcome where the coin lands heads and T {\displaystyle T} is for tails. Another possible sample space could be Ω 2 = { ( H , R ) , ( H , N R ) , ( T , R ) , ( T , N R ) } {\displaystyle \Omega _{2}=\{(H,R),(H,NR),(T,R),(T,NR)\}} . Here, R {\displaystyle R} denotes a rainy day and N R {\displaystyle NR} is a day where it is not raining. For most experiments, Ω 1 {\displaystyle \Omega _{1}} would be a better choice than Ω 2 {\displaystyle \Omega _{2}} , as an experimenter likely does not care about how the weather affects the coin toss.
For many experiments, there may be more than one plausible sample space available, depending on what result is of interest to the experimenter. For example, when drawing a card from a standard deck of fifty-two playing cards , one possibility for the sample space could be the various ranks (Ace through King), while another could be the suits (clubs, diamonds, hearts, or spades). [ 4 ] [ 14 ] A more complete description of outcomes, however, could specify both the denomination and the suit, and a sample space describing each individual card can be constructed as the Cartesian product of the two sample spaces noted above (this space would contain fifty-two equally likely outcomes). Still other sample spaces are possible, such as right-side up or upside down, if some cards have been flipped when shuffling.
Some treatments of probability assume that the various outcomes of an experiment are always defined so as to be equally likely. [ 15 ] For any sample space with N {\displaystyle N} equally likely outcomes, each outcome is assigned the probability 1 N {\displaystyle {\frac {1}{N}}} . [ 16 ] However, there are experiments that are not easily described by a sample space of equally likely outcomes—for example, if one were to toss a thumb tack many times and observe whether it landed with its point upward or downward, there is no physical symmetry to suggest that the two outcomes should be equally likely. [ 17 ]
Though most random phenomena do not have equally likely outcomes, it can be helpful to define a sample space in such a way that outcomes are at least approximately equally likely, since this condition significantly simplifies the computation of probabilities for events within the sample space. If each individual outcome occurs with the same probability, then the probability of any event becomes simply: [ 18 ] : 346–347
For example, if two fair six-sided dice are thrown to generate two uniformly distributed integers, D 1 {\displaystyle D_{1}} and D 2 {\displaystyle D_{2}} , each in the range from 1 to 6, inclusive, the 36 possible ordered pairs of outcomes ( D 1 , D 2 ) {\displaystyle (D_{1},D_{2})} constitute a sample space of equally likely events. In this case, the above formula applies, such as calculating the probability of a particular sum of the two rolls in an outcome. The probability of the event that the sum D 1 + D 2 {\displaystyle D_{1}+D_{2}} is five is 4 36 {\displaystyle {\frac {4}{36}}} , since four of the thirty-six equally likely pairs of outcomes sum to five.
If the sample space was all of the possible sums obtained from rolling two six-sided dice, the above formula can still be applied because the dice rolls are fair, but the number of outcomes in a given event will vary. A sum of two can occur with the outcome { ( 1 , 1 ) } {\displaystyle \{(1,1)\}} , so the probability is 1 36 {\displaystyle {\frac {1}{36}}} . For a sum of seven, the outcomes in the event are { ( 1 , 6 ) , ( 6 , 1 ) , ( 2 , 5 ) , ( 5 , 2 ) , ( 3 , 4 ) , ( 4 , 3 ) } {\displaystyle \{(1,6),(6,1),(2,5),(5,2),(3,4),(4,3)\}} , so the probability is 6 36 {\displaystyle {\frac {6}{36}}} . [ 19 ]
In statistics , inferences are made about characteristics of a population by studying a sample of that population's individuals. In order to arrive at a sample that presents an unbiased estimate of the true characteristics of the population, statisticians often seek to study a simple random sample —that is, a sample in which every individual in the population is equally likely to be included. [ 18 ] : 274–275 The result of this is that every possible combination of individuals who could be chosen for the sample has an equal chance to be the sample that is selected (that is, the space of simple random samples of a given size from a given population is composed of equally likely outcomes). [ 20 ]
In an elementary approach to probability , any subset of the sample space is usually called an event . [ 9 ] However, this gives rise to problems when the sample space is continuous, so that a more precise definition of an event is necessary. Under this definition only measurable subsets of the sample space, constituting a σ-algebra over the sample space itself, are considered events.
An example of an infinitely large sample space is measuring the lifetime of a light bulb. The corresponding sample space would be [0, ∞) . [ 9 ] | https://en.wikipedia.org/wiki/Sample_space |
In medicine , sampling is gathering of matter from the body to aid in the process of a medical diagnosis and/or evaluation of an indication for treatment, further medical tests or other procedures. In this sense, the sample is the gathered matter, and the sampling tool or sampler is the person or material to collect the sample.
Sampling is a prerequisite for many medical tests , but generally not for medical history , physical examination and radiologic tests .
In terms of sampling technique, a biopsy generally refers to a preparation where the normal tissue structure is preserved, availing for examination of both individual cells and their organization for the study of histology , while a sample for cytopathology is prepared primarily for the examination of individual cells, not necessarily preserving the tissue structure. Examples of biopsy procedures are bone marrow biopsy , brain biopsy , skin biopsy and liver biopsy .
Different types of matter that are sampled can be categorized by solidness versus fluidity, such as:
Body fluid sampling includes:
The sampled matter can be analyzed for various components, for example: [ citation needed ]
Microbiological sampling include: | https://en.wikipedia.org/wiki/Sampling_(medicine) |
Sampson flow is defined as fluid flow through an infinitely thin orifice in the viscous flow regime for low Reynolds number . It is derived from an analytical solution to the Navier-Stokes equations . The below equation can be used to calculate the total volumetric flowrate through such an orifice: [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ]
Here, Q S {\displaystyle Q_{S}} is the volumetric flowrate in m 3 / s e c {\displaystyle m^{3}/sec} , Δ P {\displaystyle \Delta P} is the pressure difference in Pa, d {\displaystyle d} is the pore diameter in m, and μ {\displaystyle \mu } is the fluid's dynamic viscosity in Pa·s. The flow can also be expressed as a molecular flux as:
Here, J S {\displaystyle J_{S}} is the molecular flux in atoms/m 2 ·sec, P a v e {\displaystyle P_{ave}} is the average of the pressures on either side of the orifice, k B {\displaystyle k_{B}} is the Boltzmann constant , ( 1.38 × 10 − 23 {\displaystyle 1.38\times 10^{-23}} J/K), and T {\displaystyle T} is the absolute temperature in K.
Sampson flow is the macroscopic analog of effusion flow, which describes stochastic diffusion of molecules through an orifice much smaller than the mean-free-path of the gas molecules. For pore diameters on the order of the mean-free-path of the fluid, flow will occur with contributions from the molecular regime as well as the viscous regime, obeying the dusty gas model according to the following equation: [ 6 ]
Here, Q t o t a l {\displaystyle Q_{total}} is the total volumetric flowrate and Q E {\displaystyle Q_{E}} is the volumetric flowrate according to the law of effusion . As it turns out, for many gasses, we notice equal contributions from molecular and viscous regimes when the pore size is significantly larger than the mean-free-path of the fluid, for nitrogen this occurs at a pore diameter of 393 nm, 6.0× larger than the mean-free-path . [ citation needed ] | https://en.wikipedia.org/wiki/Sampson_flow |
Samsung Galaxy Book Pro is a notebook computer announced by Samsung Electronics in April 2021. It has a 13.3 inch display with 1080p resolution and a 720p webcam. [ 1 ] [ 2 ] [ 3 ] [ 4 ]
This computing article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Samsung_Galaxy_Book_Pro |
The Samsung Galaxy Gear is a smartwatch produced by Samsung Electronics in the Samsung Gear family of devices. Unveiled during a Samsung Unpacked event in Berlin , Germany on September 4, 2013, the device serves as a companion for all Samsung Galaxy smartphones and tablets which runs on Android 4.3 "Jelly Bean" or newer. It was released on September 25, 2013. Originally released as an Android -based device, Samsung replaced the operating system with Tizen through the May 2014 software update.
The Gear's successor, the Gear 2 , was released on April 11, 2014.
The development of the Galaxy Gear came in the midst of a push towards the growing smartwatch market; Samsung's main competitor Apple had been the subject of rumors suggesting an upcoming watch product , while the Kickstarter -backed Pebble (which reached mass-market availability in July 2013) has been credited with creating mainstream interest in the concept. Lee Young-hee, vice president of Samsung's mobile business, revealed in July 2013 that the company had been working on a watch for a long time, and referred to it as a "product for the future". [ 1 ] [ 2 ] In August 2013, Bloomberg reported that "two people familiar with the matter" claimed Samsung would introduce a smartwatch, tentatively known as the 'Galaxy Gear', on September 4, 2013 during a Samsung Unpacked event prior to the IFA consumer electronics trade show in Berlin . Samsung was also expected to unveil the Galaxy Note 3 phablet during the event as well. [ 3 ] [ 4 ]
In an interview with The Korea Times published on August 27, 2013, Lee Young-hee stated that the Galaxy Gear would "enhance and enrich the current smart mobile experience in many ways", would "lead a new trend in smart mobile communications", and "add meaningful momentum to the mobile industry. [ 5 ]
Samsung officially unveiled the Galaxy Gear on September 4, 2013, with a release date set for September 25, 2013 (although its release in the United States and Japan would be delayed into October). Some wireless service providers, as an incentive, have also offered the Galaxy Gear as part of a bundle with the Galaxy Note 3. [ 6 ] [ 7 ]
To promote the Galaxy Gear, Samsung released two television advertisements, "Evolution" and "A Long Time Coming". Both ads showcased historical depictions of smartwatch-like devices in popular culture (including those seen in Dick Tracy , Star Trek , The Jetsons , Predator , and Inspector Gadget ), with the tagline "After all these years, it's finally real." [ 8 ] [ 9 ]
Samsung Galaxy Gear's watch design was exclusively leaked to VentureBeat reporter Christina Farr by an unnamed source several days prior to its Berlin release on September 4, 2013, generating widespread global interest. [ 10 ]
The Galaxy Gear is powered by a dual-core , 1,600 MHz Exynos 4212 system-on-chip , that was scaled back to one CPU core , 800 MHz to help save battery life, and contains a 320-pixel-wide square-shaped Super AMOLED touchscreen display with a pixel density of 277 ppi. Its band contains a 1.9-megapixel camera with a back-illuminated sensor , auto-focus, and 720p video recording, along with a speaker and two noise-cancelling microphones. The Galaxy Gear also includes 4 GB of internal memory, 512 MB of RAM, an accelerometer , and a gyroscope . The device contains a 315 mAh battery; the device itself does not contain a charging port and must be placed inside a special Micro USB -equipped charging case, which also contains an NFC tag that is used for the initial setup of the device. [ 11 ] [ 12 ] The Galaxy Gear is designed to IP55 specifications with dust resistance and protection from short-term exposure to water jets. [ 13 ]
To communicate with a host device, the Galaxy Gear uses Bluetooth Low Energy . As only Android 4.3 and later offer native support for Bluetooth LE, only the Galaxy Note 3 and Galaxy Note 10.1 2014 Edition , the first Samsung devices to ship with 4.3, were supported by the Galaxy Gear on launch. Shortly after the release of the Galaxy Gear, Samsung began rolling out Android 4.3 updates for its other recent devices, such as the Galaxy S III , S4 and Note II , to ensure Galaxy Gear compatibility. [ 11 ] [ 14 ]
The Galaxy Gear uses an Android or Tizen -based operating system with a minimalistic interface and gesture-based navigation. To pair the watch with a smartphone or tablet as its host device, the user must first install the Gear Manager app. An NFC tag located inside the charging case is used to download the app. Gear Manager uses Bluetooth to coordinate the pairing process and further communication with the device. It can also be used to configure the device's settings (such as the clock display's color and appearance), and to manage and install apps via Samsung Apps. [ 15 ] [ 16 ]
Notifications can be synced from the host device and displayed on the Gear's screen when received; a preview of a notification's content is displayed on the watch itself, while the Smart Relay feature allows users to open content displayed on Gear on their smartphone or tablet. S Voice can be used for basic voice commands and voice dictation for certain apps. Phone calls can also be answered and placed from the watch (the dialer is launched by swiping up on the clock display), while the "Find My Device" tool can be used to locate the watch with a phone or tablet, or vice versa. [ 15 ] [ 16 ]
The camera app can take photos, or record videos up to 15 seconds in length. Photos and videos can be stored to the device's internal storage, or immediately transferred to the user's phone or tablet. Users can also record up to 5 minutes' worth of voice memos. A media controller for music or video being played by the phone or tablet is also provided. [ 15 ] [ 16 ] [ 17 ] [ 18 ] [ 19 ]
While it is possible to sideload other Android apps on the device over Android Debug Bridge (ADB), their usability is impaired by the small screen, and an inability to access the Internet directly. [ 20 ]
On May 30, 2014, Samsung released the version 2.2 firmware update for the Galaxy Gear through its Kies desktop software. The update replaces the Android-based operating system of the device with the Tizen -based operating system of its successor, the Samsung Gear 2 . The new software, among other improvements, provides improved performance and battery life, a voice-controlled camera, and a standalone music player that can play tracks stored in the device's internal storage. [ 21 ] [ 22 ] [ 23 ]
The Galaxy Gear received generally negative comments from critics. The design of the Gear itself was met with mixed reactions; although considered high quality, the incorporation of components directly into its strap was criticized for making it inflexible (and thus making the device hard to wear comfortably). The Gear was also criticized for the limited functionality of its apps, along with its initially inconsistent notification system. As an example, critics pointed out that the Android IMAP / POP3 email client was able to display full notifications with message previews on the Galaxy Gear, while Gmail was only able to display an icon and directed users to open the message on their phone instead. [ 17 ] [ 18 ] These limitations surrounding notifications were addressed in the Galaxy Gear's first firmware update, which allows all apps to display notifications with previews on the Galaxy Gear. [ 19 ]
On the topic, The Verge remarked that "as with industrial design , software engineering isn't among Samsung's strengths, and the results on the Gear are a painful mix of unreliability and inadequacy." The ability to answer phone calls on the device was praised for its convenience and good call quality (drawing comparisons to Dick Tracy ), while its camera was also praised for having unexpectedly decent quality for its megapixel size. [ 17 ] [ 18 ] The device's reliance on Samsung Galaxy devices with specific versions of Android was also criticized, along with its poor battery life, which was considered more comparable to a smartphone than a watch. [ 15 ] [ 16 ] [ 24 ]
In an infographic posted in September 2013, TUAW compared the Galaxy Gear to the sixth-generation iPod Nano (which attracted unofficial watchband accessories due to its similarly square form factor) [ 25 ] considering the three-year-old MP3 player to be a "better, cheaper [smart]watch" than the Galaxy Gear because it is not dependent on a "host" smartphone or tablet, and contained a larger number of features than the Galaxy Gear (including the ability to, primarily, store and play music from the device itself). [ 26 ]
The Galaxy Gear performed poorly in terms of commercial sales; in late October 2013, it was reported that at least 30% of the Galaxy Gear watches sold by the U.S.-based chain Best Buy were being returned by unsatisfied customers. [ 27 ] In November 2013, Reuters reported that company sources claimed that 800,000 Galaxy Gears were sold worldwide; however, the Korean news agency Yonhap disputed the report, believing that the numbers actually referred to units shipped and not units sold. [ 7 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_Gear |
The Samsung Galaxy S24 is a series of high-end Android -based smartphones developed, manufactured, and marketed by Samsung Electronics as part of its flagship Galaxy S series . They collectively serve as the successor to the Galaxy S23 series. [ 6 ] [ 7 ] The phones were announced on January 17, 2024, at the Galaxy Unpacked event in San Jose, California , [ 8 ] [ 9 ] while the Fan Edition model was unveiled at Samsung's Galaxy Unpacked event on September 26, 2024. [ 10 ]
The first three phones were released in the United States and Europe on January 31, 2024, while the Fan Edition was released globally on October 3, 2024. They were succeeded by the Galaxy S25 series announced on January 22, 2025. [ 11 ]
The Galaxy S24 series includes four devices, which share the same lineup and screen sizes as the previous Galaxy S23 series. The flagship Galaxy S24 features a flat 6.2-inch (155 mm) display. The Galaxy S24+ features similar hardware in a 6.7-inch (168 mm) form factor. The Galaxy S24 Ultra features a flat 6.8-inch (173 mm) display, with sharp edges, distinct from its base model counterpart. The S24 and S24+ phones are powered by Snapdragon 8 Gen 3 in the U.S., Canada, China, Macau, Hong Kong, Taiwan, and Japan, while a Exynos 2400 is used in the rest of the world. The S24 Ultra is equipped with the Snapdragon 8 Gen 3 in every market. [ 12 ] [ 13 ] Conversely, the S24 FE comes with an underclocked variant of the Exynos 2400 called the Exynos 2400e in every market including North America. [ 14 ]
The Galaxy S24 and S24+ have aluminum and matte glass versions and are available in four standard colors: Amber Yellow, Marble Gray, Cobalt Violet, and Onyx Black, with three additional colors available only through Samsung's website: Jade Green, Sapphire Blue and Sandstone Orange. The S24 Ultra features titanium versions of these colors. [ 15 ] The Galaxy S24 FE has a limited set of 5 colors called Blue, Graphite, Gray, Mint, and Yellow.
The Galaxy S24 and S24+ use a "Dynamic AMOLED 2X" display with HDR10+ support, 2600 nits of peak brightness, LTPO backplane, "dynamic tone mapping" technology, and Corning Gorilla Glass Victus 2. [ 16 ] The Galaxy S24 FE has 1900 nits of peak brightness and LTPS backplane. All models use an ultrasonic in-screen fingerprint sensor , except the S24 FE which uses an optical in-screen fingerprint sensor. The S24 series uses a variable refresh rate display with a range of 1 Hz or 24 Hz to 120 Hz, [ 17 ] except the S24 FE which has a range of 60 Hz to 120 Hz [ citation needed ] .
The Galaxy S24 Ultra, in addition to the features of the S24+, uses Corning Gorilla Glass Armor glass on its display, but it drops the curved edges seen in the Galaxy S23 Ultra & Galaxy S22 Ultra. [ 18 ]
The Galaxy S24 and S24+ have a 50 MP wide sensor, a 10 MP 3x telephoto sensor and a 12 MP ultrawide sensor. The S24 Ultra has a 200 MP wide sensor, 50 MP 5× periscope telephoto sensor, 10 MP 3x telephoto sensor, and a 12 MP ultrawide sensor. The front camera uses a 12 MP sensor on all three models.
The Galaxy S24, S24+, S24 Ultra, and S24 FE contain internal 4,000 mAh, 4,900 mAh, 5,000 mAh, and 4,700 mAh Li-ion batteries respectively. The S24 and S24 FE only charges at 25 watts, while the S24+ and S24 Ultra charge up at 45 watts charging.
The Galaxy S24, S24+, and S24 FE support 5G SA/NSA/Sub6, Wi-Fi 6E , and Bluetooth 5.3 connectivity, while the Galaxy S24 Ultra additionally supports Wi-Fi 7 and ultra-wideband (UWB). [ 21 ] All models support 5G mmWave exclusively in the US.
The Galaxy S24 phones feature 4,800 MT/s LPDDR5X memory and Universal Flash Storage 3.1 with 128 GB or version 4.0 with 256 GB and above.
The Galaxy S24 phones were released with Android 14 with Samsung's One UI 6.1 user experience. Samsung has promised 7 years of security patches and OS upgrades. [ 22 ]
All phones use Google's on-device Gemini Nano , already used by their own Pixel 8 Pro [ 23 ] and their Pixel 9 series.
Starting with the Galaxy S24 and all future Samsung Galaxy smartphones and tablets, 32-bit applications are no longer supported. Devices that were released prior to the Galaxy S24 will continue to support 32-bit apps. [ 24 ]
Some users noted the unpleasant smell of the Galaxy S24 Ultra's S Pen , likened to "burnt plastic". A moderator on Samsung's EU forums said the smell was a normal part of the pen's operation, and "isn't anything to be concerned about". [ 25 ] [ 26 ]
This smell is likely from chemical reactions to the plastic shell of the S Pen, induced by the internal heat of the phone. [ 27 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_S24 |
The Samsung Galaxy S24 is a series of high-end Android -based smartphones developed, manufactured, and marketed by Samsung Electronics as part of its flagship Galaxy S series . They collectively serve as the successor to the Galaxy S23 series. [ 6 ] [ 7 ] The phones were announced on January 17, 2024, at the Galaxy Unpacked event in San Jose, California , [ 8 ] [ 9 ] while the Fan Edition model was unveiled at Samsung's Galaxy Unpacked event on September 26, 2024. [ 10 ]
The first three phones were released in the United States and Europe on January 31, 2024, while the Fan Edition was released globally on October 3, 2024. They were succeeded by the Galaxy S25 series announced on January 22, 2025. [ 11 ]
The Galaxy S24 series includes four devices, which share the same lineup and screen sizes as the previous Galaxy S23 series. The flagship Galaxy S24 features a flat 6.2-inch (155 mm) display. The Galaxy S24+ features similar hardware in a 6.7-inch (168 mm) form factor. The Galaxy S24 Ultra features a flat 6.8-inch (173 mm) display, with sharp edges, distinct from its base model counterpart. The S24 and S24+ phones are powered by Snapdragon 8 Gen 3 in the U.S., Canada, China, Macau, Hong Kong, Taiwan, and Japan, while a Exynos 2400 is used in the rest of the world. The S24 Ultra is equipped with the Snapdragon 8 Gen 3 in every market. [ 12 ] [ 13 ] Conversely, the S24 FE comes with an underclocked variant of the Exynos 2400 called the Exynos 2400e in every market including North America. [ 14 ]
The Galaxy S24 and S24+ have aluminum and matte glass versions and are available in four standard colors: Amber Yellow, Marble Gray, Cobalt Violet, and Onyx Black, with three additional colors available only through Samsung's website: Jade Green, Sapphire Blue and Sandstone Orange. The S24 Ultra features titanium versions of these colors. [ 15 ] The Galaxy S24 FE has a limited set of 5 colors called Blue, Graphite, Gray, Mint, and Yellow.
The Galaxy S24 and S24+ use a "Dynamic AMOLED 2X" display with HDR10+ support, 2600 nits of peak brightness, LTPO backplane, "dynamic tone mapping" technology, and Corning Gorilla Glass Victus 2. [ 16 ] The Galaxy S24 FE has 1900 nits of peak brightness and LTPS backplane. All models use an ultrasonic in-screen fingerprint sensor , except the S24 FE which uses an optical in-screen fingerprint sensor. The S24 series uses a variable refresh rate display with a range of 1 Hz or 24 Hz to 120 Hz, [ 17 ] except the S24 FE which has a range of 60 Hz to 120 Hz [ citation needed ] .
The Galaxy S24 Ultra, in addition to the features of the S24+, uses Corning Gorilla Glass Armor glass on its display, but it drops the curved edges seen in the Galaxy S23 Ultra & Galaxy S22 Ultra. [ 18 ]
The Galaxy S24 and S24+ have a 50 MP wide sensor, a 10 MP 3x telephoto sensor and a 12 MP ultrawide sensor. The S24 Ultra has a 200 MP wide sensor, 50 MP 5× periscope telephoto sensor, 10 MP 3x telephoto sensor, and a 12 MP ultrawide sensor. The front camera uses a 12 MP sensor on all three models.
The Galaxy S24, S24+, S24 Ultra, and S24 FE contain internal 4,000 mAh, 4,900 mAh, 5,000 mAh, and 4,700 mAh Li-ion batteries respectively. The S24 and S24 FE only charges at 25 watts, while the S24+ and S24 Ultra charge up at 45 watts charging.
The Galaxy S24, S24+, and S24 FE support 5G SA/NSA/Sub6, Wi-Fi 6E , and Bluetooth 5.3 connectivity, while the Galaxy S24 Ultra additionally supports Wi-Fi 7 and ultra-wideband (UWB). [ 21 ] All models support 5G mmWave exclusively in the US.
The Galaxy S24 phones feature 4,800 MT/s LPDDR5X memory and Universal Flash Storage 3.1 with 128 GB or version 4.0 with 256 GB and above.
The Galaxy S24 phones were released with Android 14 with Samsung's One UI 6.1 user experience. Samsung has promised 7 years of security patches and OS upgrades. [ 22 ]
All phones use Google's on-device Gemini Nano , already used by their own Pixel 8 Pro [ 23 ] and their Pixel 9 series.
Starting with the Galaxy S24 and all future Samsung Galaxy smartphones and tablets, 32-bit applications are no longer supported. Devices that were released prior to the Galaxy S24 will continue to support 32-bit apps. [ 24 ]
Some users noted the unpleasant smell of the Galaxy S24 Ultra's S Pen , likened to "burnt plastic". A moderator on Samsung's EU forums said the smell was a normal part of the pen's operation, and "isn't anything to be concerned about". [ 25 ] [ 26 ]
This smell is likely from chemical reactions to the plastic shell of the S Pen, induced by the internal heat of the phone. [ 27 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_S24+ |
The Samsung Galaxy S24 is a series of high-end Android -based smartphones developed, manufactured, and marketed by Samsung Electronics as part of its flagship Galaxy S series . They collectively serve as the successor to the Galaxy S23 series. [ 6 ] [ 7 ] The phones were announced on January 17, 2024, at the Galaxy Unpacked event in San Jose, California , [ 8 ] [ 9 ] while the Fan Edition model was unveiled at Samsung's Galaxy Unpacked event on September 26, 2024. [ 10 ]
The first three phones were released in the United States and Europe on January 31, 2024, while the Fan Edition was released globally on October 3, 2024. They were succeeded by the Galaxy S25 series announced on January 22, 2025. [ 11 ]
The Galaxy S24 series includes four devices, which share the same lineup and screen sizes as the previous Galaxy S23 series. The flagship Galaxy S24 features a flat 6.2-inch (155 mm) display. The Galaxy S24+ features similar hardware in a 6.7-inch (168 mm) form factor. The Galaxy S24 Ultra features a flat 6.8-inch (173 mm) display, with sharp edges, distinct from its base model counterpart. The S24 and S24+ phones are powered by Snapdragon 8 Gen 3 in the U.S., Canada, China, Macau, Hong Kong, Taiwan, and Japan, while a Exynos 2400 is used in the rest of the world. The S24 Ultra is equipped with the Snapdragon 8 Gen 3 in every market. [ 12 ] [ 13 ] Conversely, the S24 FE comes with an underclocked variant of the Exynos 2400 called the Exynos 2400e in every market including North America. [ 14 ]
The Galaxy S24 and S24+ have aluminum and matte glass versions and are available in four standard colors: Amber Yellow, Marble Gray, Cobalt Violet, and Onyx Black, with three additional colors available only through Samsung's website: Jade Green, Sapphire Blue and Sandstone Orange. The S24 Ultra features titanium versions of these colors. [ 15 ] The Galaxy S24 FE has a limited set of 5 colors called Blue, Graphite, Gray, Mint, and Yellow.
The Galaxy S24 and S24+ use a "Dynamic AMOLED 2X" display with HDR10+ support, 2600 nits of peak brightness, LTPO backplane, "dynamic tone mapping" technology, and Corning Gorilla Glass Victus 2. [ 16 ] The Galaxy S24 FE has 1900 nits of peak brightness and LTPS backplane. All models use an ultrasonic in-screen fingerprint sensor , except the S24 FE which uses an optical in-screen fingerprint sensor. The S24 series uses a variable refresh rate display with a range of 1 Hz or 24 Hz to 120 Hz, [ 17 ] except the S24 FE which has a range of 60 Hz to 120 Hz [ citation needed ] .
The Galaxy S24 Ultra, in addition to the features of the S24+, uses Corning Gorilla Glass Armor glass on its display, but it drops the curved edges seen in the Galaxy S23 Ultra & Galaxy S22 Ultra. [ 18 ]
The Galaxy S24 and S24+ have a 50 MP wide sensor, a 10 MP 3x telephoto sensor and a 12 MP ultrawide sensor. The S24 Ultra has a 200 MP wide sensor, 50 MP 5× periscope telephoto sensor, 10 MP 3x telephoto sensor, and a 12 MP ultrawide sensor. The front camera uses a 12 MP sensor on all three models.
The Galaxy S24, S24+, S24 Ultra, and S24 FE contain internal 4,000 mAh, 4,900 mAh, 5,000 mAh, and 4,700 mAh Li-ion batteries respectively. The S24 and S24 FE only charges at 25 watts, while the S24+ and S24 Ultra charge up at 45 watts charging.
The Galaxy S24, S24+, and S24 FE support 5G SA/NSA/Sub6, Wi-Fi 6E , and Bluetooth 5.3 connectivity, while the Galaxy S24 Ultra additionally supports Wi-Fi 7 and ultra-wideband (UWB). [ 21 ] All models support 5G mmWave exclusively in the US.
The Galaxy S24 phones feature 4,800 MT/s LPDDR5X memory and Universal Flash Storage 3.1 with 128 GB or version 4.0 with 256 GB and above.
The Galaxy S24 phones were released with Android 14 with Samsung's One UI 6.1 user experience. Samsung has promised 7 years of security patches and OS upgrades. [ 22 ]
All phones use Google's on-device Gemini Nano , already used by their own Pixel 8 Pro [ 23 ] and their Pixel 9 series.
Starting with the Galaxy S24 and all future Samsung Galaxy smartphones and tablets, 32-bit applications are no longer supported. Devices that were released prior to the Galaxy S24 will continue to support 32-bit apps. [ 24 ]
Some users noted the unpleasant smell of the Galaxy S24 Ultra's S Pen , likened to "burnt plastic". A moderator on Samsung's EU forums said the smell was a normal part of the pen's operation, and "isn't anything to be concerned about". [ 25 ] [ 26 ]
This smell is likely from chemical reactions to the plastic shell of the S Pen, induced by the internal heat of the phone. [ 27 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_S24_Ultra |
The Samsung Galaxy S25 is a series of high-end Android -based smartphones developed and marketed by Samsung Electronics as part of its flagship Galaxy S Series . [ 6 ] [ 7 ] [ 8 ] They collectively serve as the successor to the Samsung Galaxy S24 series . The S25, S25+ and S25 Ultra models were announced on January 22, 2025, at the Galaxy Unpacked event in San Jose, California and were released on February 7, 2025. [ 9 ]
Samsung launched another model in the series, the S25 Edge, at Galaxy Unpacked on May 13, 2025. [ 10 ] [ 11 ]
The Samsung Galaxy S25 lineup includes four models: Samsung Galaxy S25, Samsung Galaxy S25+, Samsung Galaxy S25 Ultra, and the Samsung Galaxy S25 Edge. The inclusion of the latter marked the return of the Edge name which was last seen on the Samsung Galaxy S7 Edge , launched in 2016. It is also the first S series phone to have a dual rear camera setup since the Samsung Galaxy S9 .
The Galaxy S25 features a flat 6.2 in (160 mm) display and a compact form factor. The Galaxy S25+ offers similar internal hardware with a larger 6.7 in (170 mm) display. The Galaxy S25 Ultra includes a 6.9 in (180 mm) display, an enlarged frame compared to its predecessor, and rounded corners that align more closely with the design language of the Galaxy S series . [ 12 ] [ 13 ] The Galaxy S25 Edge, a new addition to the series, also has a 6.7-inch display and is the thinnest model in the lineup, at 5.85 mm thick. [ 14 ] [ 15 ] [ 16 ]
While the S25 and S25+ maintain similar dimensions to their S24 counterparts, the S25 Ultra introduces subtle design refinements, and the S25 Edge differentiates itself by featuring a significantly thinner chassis. [ 17 ]
All models are powered by the Snapdragon 8 Elite chipset, which, unlike previous Galaxy S generations that varied by region, is used uniformly across all global variants. [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 18 ] The Galaxy S25, S25+, S25 Ultra and S25 Edge all offer the same eSIM functionality within each respective region. International variants support dual Nano-SIM slots along with dual eSIM profiles. U.S. models include a single Nano-SIM slot with dual eSIM support, while Chinese versions retain the traditional dual Nano-SIM configuration without eSIM capability. [ 19 ]
The S25 and S25+ smartphones have an aluminium body and a glass back, similar to the design of their predecessors. Both the S25 and S25+ use Gorilla Glass Victus 2 for both the front display and rear glass panel. [ 20 ]
They come in four standard colours: Icy Blue, Mint, Navy and Silver Shadow, with an additional three colours being available only through Samsung's online website: Pink Gold, Coral Red and Blue Black. [ 21 ] [ 22 ]
The S25 Ultra has a titanium body and a glass back, similar to the S24 Ultra. However, the S25 Ultra features rounded corners, departing from the S24 Ultra 's squared corners. Additionally, the S25 Ultra uses Gorilla Glass Armor 2 for its front display and rear panel for improved durability and reduced glare.
The S25 Ultra comes in four standard colours: Titanium Silver Blue, Titanium Black, Titanium White Silver and Titanium Grey, as well as three additional colours that are only available through Samsung's online website: Titanium Jade Green, Titanium Jet Black and Titanium Pink Gold. [ 23 ]
The S25 Edge features a titanium body and a flat display design, similar to the S25 and S25+, but with a slimmer profile. It uses Gorilla Glass Ceramic 2 on the front for enhanced scratch resistance and reduced reflectivity. The S25 Edge is available in three colours: Titanium Icy Blue, Titanium Silver, and Titanium Jet Black. [ 24 ] [ 25 ] [ 26 ]
The S25 series of phones use a "Dynamic LTPO AMOLED 2X" display with HDR10+ support, a display that can go up to 120 Hz refresh rate and 2600 nits peak brightness. Additionally, the S25 and S25+ phones feature a Corning Gorilla Glass Victus 2 as protection for the display, [ 1 ] [ 2 ] whereas the S25 Ultra uses a Corning Gorilla Glass Armor 2 as its protection for the display. [ 4 ] All phones in the series feature an ultrasonic in-screen fingerprint sensor . The S25 Edge also features a "Dynamic LTPO AMOLED 2X" panel with HDR10+ and 120 Hz refresh rate support, matching the peak brightness of 2600 nits. It uses Corning Gorilla Glass Victus 2 for screen protection, similar to the base S25 and S25+. [ 27 ] [ 28 ] [ 29 ]
Both the S25 and S25+ have a 50 MP wide sensor, a 10 MP 3x telephoto lens and a 12 MP ultrawide sensor.
On the other hand, the S25 Ultra has a 200 MP wide sensor, a 50 MP 5x periscope telephoto lens, a 10 MP 3x telephoto lens, and a 50 MP ultrawide sensor.
The S25 Edge has a 200 MP wide sensor and a 12 MP ultrawide sensor, with no telephoto lens. [ 30 ]
All four models feature a 12 MP sensor for the front-facing camera. [ 31 ]
The Galaxy S25 models contain similarly sized batteries to the previous S24 models, with the exception of the S25 Edge. Due to its decreased thickness, it has a smaller battery than the S25+ despite having a nearly identical height and width. The S25 and S25 Edge support wired charging at up to 25 W while the S25+ and S25 Ultra have faster 45 W charging. All four support Qi inductive charging up to 15 W, and can charge other Qi-compatible devices wirelessly using battery power.
[ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 32 ] [ 33 ]
Unlike previous generations, all Samsung Galaxy S25 models launched with 12 GB of RAM. The S25 starts at 128 GB of storage, while the other three models start at 256 GB of storage. The S25 Edge also comes standard with 12 GB of RAM and does not offer configurable RAM options.
However, in South Korea and Greater China (Mainland China, Hong Kong and Taiwan) markets, a 16 GB RAM option exists for certain Samsung Galaxy S25 Ultra models. For South Korean models, Titanium Jetblack phones with 1 TB of storage come with 16 GB of RAM. For Greater China, regardless of color choice, the 1 TB storage option comes with 16 GB of RAM.
[ 1 ] [ 2 ] [ 3 ] [ 4 ]
All models in the Galaxy S25 series support 5G connectivity, Wi-Fi 7, Bluetooth 5.4, NFC, and USB Type-C 3.2 for data transfer and charging.
Ultra-Wideband (UWB) is supported only on the S25+, S25 Edge, [ 34 ] and S25 Ultra models.
[ 1 ] [ 2 ] [ 3 ] [ 4 ]
The Galaxy S25 phones were launched with Android 15 and One UI 7 . Samsung has promised 7 years of OS and security updates to the S25 series of phones (meaning support may end in 2032). [ 35 ]
The devices are additionally shipped with Galaxy AI , Samsung's advanced suite of artificial intelligence features. As a relatively new technology, it has received updated capabilities in the S25 series. [ 36 ]
With the release of the S25 Ultra, Samsung opted to remove the Bluetooth functionality in its trademark S Pen , a feature added to the stylus with the Galaxy Note 9 in 2018. Samsung sought to remove the Bluetooth features as a cost-saving measure, claiming it was used by less than 1% of Galaxy users. [ 37 ]
Among the functions lost in are remote camera control, air actions, and several in-app features for programs such as PowerPoint or the native Gallery app. [ 38 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_S25 |
The Samsung Galaxy S25 is a series of high-end Android -based smartphones developed and marketed by Samsung Electronics as part of its flagship Galaxy S Series . [ 6 ] [ 7 ] [ 8 ] They collectively serve as the successor to the Samsung Galaxy S24 series . The S25, S25+ and S25 Ultra models were announced on January 22, 2025, at the Galaxy Unpacked event in San Jose, California and were released on February 7, 2025. [ 9 ]
Samsung launched another model in the series, the S25 Edge, at Galaxy Unpacked on May 13, 2025. [ 10 ] [ 11 ]
The Samsung Galaxy S25 lineup includes four models: Samsung Galaxy S25, Samsung Galaxy S25+, Samsung Galaxy S25 Ultra, and the Samsung Galaxy S25 Edge. The inclusion of the latter marked the return of the Edge name which was last seen on the Samsung Galaxy S7 Edge , launched in 2016. It is also the first S series phone to have a dual rear camera setup since the Samsung Galaxy S9 .
The Galaxy S25 features a flat 6.2 in (160 mm) display and a compact form factor. The Galaxy S25+ offers similar internal hardware with a larger 6.7 in (170 mm) display. The Galaxy S25 Ultra includes a 6.9 in (180 mm) display, an enlarged frame compared to its predecessor, and rounded corners that align more closely with the design language of the Galaxy S series . [ 12 ] [ 13 ] The Galaxy S25 Edge, a new addition to the series, also has a 6.7-inch display and is the thinnest model in the lineup, at 5.85 mm thick. [ 14 ] [ 15 ] [ 16 ]
While the S25 and S25+ maintain similar dimensions to their S24 counterparts, the S25 Ultra introduces subtle design refinements, and the S25 Edge differentiates itself by featuring a significantly thinner chassis. [ 17 ]
All models are powered by the Snapdragon 8 Elite chipset, which, unlike previous Galaxy S generations that varied by region, is used uniformly across all global variants. [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 18 ] The Galaxy S25, S25+, S25 Ultra and S25 Edge all offer the same eSIM functionality within each respective region. International variants support dual Nano-SIM slots along with dual eSIM profiles. U.S. models include a single Nano-SIM slot with dual eSIM support, while Chinese versions retain the traditional dual Nano-SIM configuration without eSIM capability. [ 19 ]
The S25 and S25+ smartphones have an aluminium body and a glass back, similar to the design of their predecessors. Both the S25 and S25+ use Gorilla Glass Victus 2 for both the front display and rear glass panel. [ 20 ]
They come in four standard colours: Icy Blue, Mint, Navy and Silver Shadow, with an additional three colours being available only through Samsung's online website: Pink Gold, Coral Red and Blue Black. [ 21 ] [ 22 ]
The S25 Ultra has a titanium body and a glass back, similar to the S24 Ultra. However, the S25 Ultra features rounded corners, departing from the S24 Ultra 's squared corners. Additionally, the S25 Ultra uses Gorilla Glass Armor 2 for its front display and rear panel for improved durability and reduced glare.
The S25 Ultra comes in four standard colours: Titanium Silver Blue, Titanium Black, Titanium White Silver and Titanium Grey, as well as three additional colours that are only available through Samsung's online website: Titanium Jade Green, Titanium Jet Black and Titanium Pink Gold. [ 23 ]
The S25 Edge features a titanium body and a flat display design, similar to the S25 and S25+, but with a slimmer profile. It uses Gorilla Glass Ceramic 2 on the front for enhanced scratch resistance and reduced reflectivity. The S25 Edge is available in three colours: Titanium Icy Blue, Titanium Silver, and Titanium Jet Black. [ 24 ] [ 25 ] [ 26 ]
The S25 series of phones use a "Dynamic LTPO AMOLED 2X" display with HDR10+ support, a display that can go up to 120 Hz refresh rate and 2600 nits peak brightness. Additionally, the S25 and S25+ phones feature a Corning Gorilla Glass Victus 2 as protection for the display, [ 1 ] [ 2 ] whereas the S25 Ultra uses a Corning Gorilla Glass Armor 2 as its protection for the display. [ 4 ] All phones in the series feature an ultrasonic in-screen fingerprint sensor . The S25 Edge also features a "Dynamic LTPO AMOLED 2X" panel with HDR10+ and 120 Hz refresh rate support, matching the peak brightness of 2600 nits. It uses Corning Gorilla Glass Victus 2 for screen protection, similar to the base S25 and S25+. [ 27 ] [ 28 ] [ 29 ]
Both the S25 and S25+ have a 50 MP wide sensor, a 10 MP 3x telephoto lens and a 12 MP ultrawide sensor.
On the other hand, the S25 Ultra has a 200 MP wide sensor, a 50 MP 5x periscope telephoto lens, a 10 MP 3x telephoto lens, and a 50 MP ultrawide sensor.
The S25 Edge has a 200 MP wide sensor and a 12 MP ultrawide sensor, with no telephoto lens. [ 30 ]
All four models feature a 12 MP sensor for the front-facing camera. [ 31 ]
The Galaxy S25 models contain similarly sized batteries to the previous S24 models, with the exception of the S25 Edge. Due to its decreased thickness, it has a smaller battery than the S25+ despite having a nearly identical height and width. The S25 and S25 Edge support wired charging at up to 25 W while the S25+ and S25 Ultra have faster 45 W charging. All four support Qi inductive charging up to 15 W, and can charge other Qi-compatible devices wirelessly using battery power.
[ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 32 ] [ 33 ]
Unlike previous generations, all Samsung Galaxy S25 models launched with 12 GB of RAM. The S25 starts at 128 GB of storage, while the other three models start at 256 GB of storage. The S25 Edge also comes standard with 12 GB of RAM and does not offer configurable RAM options.
However, in South Korea and Greater China (Mainland China, Hong Kong and Taiwan) markets, a 16 GB RAM option exists for certain Samsung Galaxy S25 Ultra models. For South Korean models, Titanium Jetblack phones with 1 TB of storage come with 16 GB of RAM. For Greater China, regardless of color choice, the 1 TB storage option comes with 16 GB of RAM.
[ 1 ] [ 2 ] [ 3 ] [ 4 ]
All models in the Galaxy S25 series support 5G connectivity, Wi-Fi 7, Bluetooth 5.4, NFC, and USB Type-C 3.2 for data transfer and charging.
Ultra-Wideband (UWB) is supported only on the S25+, S25 Edge, [ 34 ] and S25 Ultra models.
[ 1 ] [ 2 ] [ 3 ] [ 4 ]
The Galaxy S25 phones were launched with Android 15 and One UI 7 . Samsung has promised 7 years of OS and security updates to the S25 series of phones (meaning support may end in 2032). [ 35 ]
The devices are additionally shipped with Galaxy AI , Samsung's advanced suite of artificial intelligence features. As a relatively new technology, it has received updated capabilities in the S25 series. [ 36 ]
With the release of the S25 Ultra, Samsung opted to remove the Bluetooth functionality in its trademark S Pen , a feature added to the stylus with the Galaxy Note 9 in 2018. Samsung sought to remove the Bluetooth features as a cost-saving measure, claiming it was used by less than 1% of Galaxy users. [ 37 ]
Among the functions lost in are remote camera control, air actions, and several in-app features for programs such as PowerPoint or the native Gallery app. [ 38 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_S25+ |
The Samsung Galaxy S25 is a series of high-end Android -based smartphones developed and marketed by Samsung Electronics as part of its flagship Galaxy S Series . [ 6 ] [ 7 ] [ 8 ] They collectively serve as the successor to the Samsung Galaxy S24 series . The S25, S25+ and S25 Ultra models were announced on January 22, 2025, at the Galaxy Unpacked event in San Jose, California and were released on February 7, 2025. [ 9 ]
Samsung launched another model in the series, the S25 Edge, at Galaxy Unpacked on May 13, 2025. [ 10 ] [ 11 ]
The Samsung Galaxy S25 lineup includes four models: Samsung Galaxy S25, Samsung Galaxy S25+, Samsung Galaxy S25 Ultra, and the Samsung Galaxy S25 Edge. The inclusion of the latter marked the return of the Edge name which was last seen on the Samsung Galaxy S7 Edge , launched in 2016. It is also the first S series phone to have a dual rear camera setup since the Samsung Galaxy S9 .
The Galaxy S25 features a flat 6.2 in (160 mm) display and a compact form factor. The Galaxy S25+ offers similar internal hardware with a larger 6.7 in (170 mm) display. The Galaxy S25 Ultra includes a 6.9 in (180 mm) display, an enlarged frame compared to its predecessor, and rounded corners that align more closely with the design language of the Galaxy S series . [ 12 ] [ 13 ] The Galaxy S25 Edge, a new addition to the series, also has a 6.7-inch display and is the thinnest model in the lineup, at 5.85 mm thick. [ 14 ] [ 15 ] [ 16 ]
While the S25 and S25+ maintain similar dimensions to their S24 counterparts, the S25 Ultra introduces subtle design refinements, and the S25 Edge differentiates itself by featuring a significantly thinner chassis. [ 17 ]
All models are powered by the Snapdragon 8 Elite chipset, which, unlike previous Galaxy S generations that varied by region, is used uniformly across all global variants. [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 18 ] The Galaxy S25, S25+, S25 Ultra and S25 Edge all offer the same eSIM functionality within each respective region. International variants support dual Nano-SIM slots along with dual eSIM profiles. U.S. models include a single Nano-SIM slot with dual eSIM support, while Chinese versions retain the traditional dual Nano-SIM configuration without eSIM capability. [ 19 ]
The S25 and S25+ smartphones have an aluminium body and a glass back, similar to the design of their predecessors. Both the S25 and S25+ use Gorilla Glass Victus 2 for both the front display and rear glass panel. [ 20 ]
They come in four standard colours: Icy Blue, Mint, Navy and Silver Shadow, with an additional three colours being available only through Samsung's online website: Pink Gold, Coral Red and Blue Black. [ 21 ] [ 22 ]
The S25 Ultra has a titanium body and a glass back, similar to the S24 Ultra. However, the S25 Ultra features rounded corners, departing from the S24 Ultra 's squared corners. Additionally, the S25 Ultra uses Gorilla Glass Armor 2 for its front display and rear panel for improved durability and reduced glare.
The S25 Ultra comes in four standard colours: Titanium Silver Blue, Titanium Black, Titanium White Silver and Titanium Grey, as well as three additional colours that are only available through Samsung's online website: Titanium Jade Green, Titanium Jet Black and Titanium Pink Gold. [ 23 ]
The S25 Edge features a titanium body and a flat display design, similar to the S25 and S25+, but with a slimmer profile. It uses Gorilla Glass Ceramic 2 on the front for enhanced scratch resistance and reduced reflectivity. The S25 Edge is available in three colours: Titanium Icy Blue, Titanium Silver, and Titanium Jet Black. [ 24 ] [ 25 ] [ 26 ]
The S25 series of phones use a "Dynamic LTPO AMOLED 2X" display with HDR10+ support, a display that can go up to 120 Hz refresh rate and 2600 nits peak brightness. Additionally, the S25 and S25+ phones feature a Corning Gorilla Glass Victus 2 as protection for the display, [ 1 ] [ 2 ] whereas the S25 Ultra uses a Corning Gorilla Glass Armor 2 as its protection for the display. [ 4 ] All phones in the series feature an ultrasonic in-screen fingerprint sensor . The S25 Edge also features a "Dynamic LTPO AMOLED 2X" panel with HDR10+ and 120 Hz refresh rate support, matching the peak brightness of 2600 nits. It uses Corning Gorilla Glass Victus 2 for screen protection, similar to the base S25 and S25+. [ 27 ] [ 28 ] [ 29 ]
Both the S25 and S25+ have a 50 MP wide sensor, a 10 MP 3x telephoto lens and a 12 MP ultrawide sensor.
On the other hand, the S25 Ultra has a 200 MP wide sensor, a 50 MP 5x periscope telephoto lens, a 10 MP 3x telephoto lens, and a 50 MP ultrawide sensor.
The S25 Edge has a 200 MP wide sensor and a 12 MP ultrawide sensor, with no telephoto lens. [ 30 ]
All four models feature a 12 MP sensor for the front-facing camera. [ 31 ]
The Galaxy S25 models contain similarly sized batteries to the previous S24 models, with the exception of the S25 Edge. Due to its decreased thickness, it has a smaller battery than the S25+ despite having a nearly identical height and width. The S25 and S25 Edge support wired charging at up to 25 W while the S25+ and S25 Ultra have faster 45 W charging. All four support Qi inductive charging up to 15 W, and can charge other Qi-compatible devices wirelessly using battery power.
[ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 32 ] [ 33 ]
Unlike previous generations, all Samsung Galaxy S25 models launched with 12 GB of RAM. The S25 starts at 128 GB of storage, while the other three models start at 256 GB of storage. The S25 Edge also comes standard with 12 GB of RAM and does not offer configurable RAM options.
However, in South Korea and Greater China (Mainland China, Hong Kong and Taiwan) markets, a 16 GB RAM option exists for certain Samsung Galaxy S25 Ultra models. For South Korean models, Titanium Jetblack phones with 1 TB of storage come with 16 GB of RAM. For Greater China, regardless of color choice, the 1 TB storage option comes with 16 GB of RAM.
[ 1 ] [ 2 ] [ 3 ] [ 4 ]
All models in the Galaxy S25 series support 5G connectivity, Wi-Fi 7, Bluetooth 5.4, NFC, and USB Type-C 3.2 for data transfer and charging.
Ultra-Wideband (UWB) is supported only on the S25+, S25 Edge, [ 34 ] and S25 Ultra models.
[ 1 ] [ 2 ] [ 3 ] [ 4 ]
The Galaxy S25 phones were launched with Android 15 and One UI 7 . Samsung has promised 7 years of OS and security updates to the S25 series of phones (meaning support may end in 2032). [ 35 ]
The devices are additionally shipped with Galaxy AI , Samsung's advanced suite of artificial intelligence features. As a relatively new technology, it has received updated capabilities in the S25 series. [ 36 ]
With the release of the S25 Ultra, Samsung opted to remove the Bluetooth functionality in its trademark S Pen , a feature added to the stylus with the Galaxy Note 9 in 2018. Samsung sought to remove the Bluetooth features as a cost-saving measure, claiming it was used by less than 1% of Galaxy users. [ 37 ]
Among the functions lost in are remote camera control, air actions, and several in-app features for programs such as PowerPoint or the native Gallery app. [ 38 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_S25_Ultra |
The Samsung Galaxy Watch is a smartwatch developed by Samsung Electronics . It was announced on 9 August 2018. [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ] [ 9 ] The Galaxy Watch was scheduled for availability in the United States starting on 24 August 2018, at select carriers and retail locations in South Korea on 31 August 2018, and in additional select markets on 14 September 2018. [ 10 ]
On 27 February 2021, Shortly after the Galaxy Watch Active2 and Galaxy Watch3 received an update unlocking the ECG feature for the European countries, Samsung is now delivering Galaxy Watch3-intrinsic features to the original Galaxy Watch and Watch Active. [ 11 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_Watch |
The Samsung Galaxy Watch 3 (stylized as Samsung Galaxy Watch3 ) is a smartwatch developed by Samsung Electronics that was released on August 5, 2020 at Samsung's Unpacked Event alongside the flagships of the Galaxy Note series and Galaxy Z series , i.e., the Samsung Galaxy Note 20 and Samsung Galaxy Z Fold 2 , respectively. [ 2 ] [ 3 ] [ 4 ] [ 5 ] [ 6 ]
Due to limitations of the COVID-19 pandemic on certain social gatherings, the smartwatch was released via Samsung's online channels. [ 5 ] [ 4 ] [ 3 ]
The Galaxy Watch 3 comes with a 1.4 (360×360) inch circular Super AMOLED display with a pixel density of 257 ppi (360 pixels/1.4 inches= 257.14 Pixels/Inch), powered by a non-removable 340 mAh battery and recharged using Qi inductive charging . The smartwatch has 1 GB of RAM and 8 GB of internal storage. The Galaxy Watch 3 also features a fully rotatable physical bezel with the display glass made from Corning Gorilla Glass DX . The device is compatible with a 20 or 22 mm straps, depending on model. The Galaxy Watch 3 comes in Bronze, Black, and Silver colour options. [ 1 ]
Titanium frame model with metal strap (accepts all 22 mm watch straps/bands)
Water Resistance
US carrier support: Verizon , T-Mobile/Sprint , AT&T
GSM / HSPA / LTE , 2G/GSM/850/900/1800/2100, 3G/HSDPA/850/900/2100
Korea-only LTE models (SM-R845N, SM-R855N), via eSIM : LTE bands 1/3/5/7/8; UTMS bands 1/5/8
The smartwatch was released with Tizen 5.5 that features Samsung's unique software overlay. [ 1 ]
The Galaxy Watch 3 has a retail price of US$399 for the 41 mm and US$479 for the 45 mm option. [ 1 ]
Ars Technica called Galaxy Watch 3 a "refresh" of Galaxy Watch Active2, which does not have "a ton in the way of new features outside of added fall detection", but "offers all the conveniences you’d expect, like the ability to take calls, check voicemails, and send texts". [ 7 ]
Engadget called Galaxy Watch 3 "the best non-Apple smartwatch". [ 11 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_Watch_3 |
The Samsung Galaxy Watch 4 (stylized as Samsung Galaxy Watch4 ) is a smartwatch developed by Samsung Electronics . It is the first Samsung watch to run Google's Wear OS since the Samsung Gear Live , and the first watch to run Wear OS 3, co-developed by Samsung and Google . [ 3 ] The device largely followed the design language of the preceding Samsung Galaxy Watch Active and Galaxy Watch 3 , but including all new software. [ 4 ] The watch also included EKG, body compositional analysis, and blood pressure monitoring via the new Samsung BioActive sensor. [ 5 ] It was announced on August 11, 2021, at Samsung's Unpacked Event alongside the Samsung Galaxy Z Flip 3 , Samsung Galaxy Z Fold 3 and Galaxy Buds 2 . [ 6 ] The watch was released worldwide on August 27, 2021.
[ 2 ]
The smartwatch was the first watch released by Samsung to use Wear OS instead of Samsung's own Tizen OS . [ 7 ]
This smartwatch is region locked in mainland China, unlike past models.
Unlike past Wear OS devices, Wear OS 3 supports a wider variety of languages that the end user can choose from. An ADB command can be used to temporarily change the watch's language to another one, which will reset when the device is reconnected to the phone.
Depending on the region where the device was sold from, the language and region options may differ. | https://en.wikipedia.org/wiki/Samsung_Galaxy_Watch_4 |
The Samsung Galaxy Watch 5 (stylized as Samsung Galaxy Watch5 ) is a series of Wear OS -based smartwatches developed by Samsung Electronics . It was announced on 10 August 2022, [ 6 ] [ 7 ] and was released on 26 August 2022. [ 8 ] [ 9 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_Watch_5 |
The Samsung Galaxy Watch 6 (stylized as Samsung Galaxy Watch6 ) is a series of Wear OS -based smartwatches developed by Samsung Electronics . It was announced on July 26, 2023 at Samsung's biannual Galaxy Unpacked event in Seoul, South Korea , making it the first such release held in the company's home country. [ 1 ] [ 2 ] [ 3 ] [ 4 ] The watches were released on August 11, 2023. | https://en.wikipedia.org/wiki/Samsung_Galaxy_Watch_6 |
The Samsung Galaxy Watch 7 (stylized as Samsung Galaxy Watch7 ) is a series of Wear OS -based smartwatches developed by Samsung Electronics . It was announced on July 10, 2024, at Samsung's biannual Galaxy Unpacked event. [ 1 ] [ 2 ] [ 3 ] [ 4 ] The watches were launched on July 24, 2024. | https://en.wikipedia.org/wiki/Samsung_Galaxy_Watch_7 |
The Samsung Galaxy Watch Active is a smartwatch developed by Samsung Electronics . It was announced on 20 February 2019. [ 1 ] The Galaxy Watch Active was scheduled for availability in the United States starting on March 8, 2019.
This technology-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Samsung_Galaxy_Watch_Active |
The Samsung Galaxy Watch Active 2 (stylized as Samsung Galaxy Watch Active2 ) is a smartwatch developed by Samsung Electronics , running the Tizen operating system. Announced on 5 August 2019, the Active 2 was scheduled for availability in the United States starting on 23 September 2019. [ 1 ]
The Active 2 was released in two sizes, 40 mm or 44 mm, and two connectivity formats, either Bluetooth or LTE capability. The LTE version functions as a standalone phone and allows a user to call, text, pay, and stream music or video without a nearby smartphone. [ 2 ] An Under Armour Edition of the Active 2 was released on October 11, 2019, containing a watch face and strap branded with the Under Armour logo. [ 3 ] [ 4 ]
Samsung announced as part of the move to move from Tizen OS to Wear OS by Google starting from August 2022. The Watch Active 2 will stop receiving software and security updates, while the Watch 3 will stop receiving software updates in 2023. [ citation needed ]
[ 6 ]
This technology-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Samsung_Galaxy_Watch_Active_2 |
The Samsung Galaxy Watch series is a line of smartwatches designed and produced by Samsung Electronics . The line features various health, fitness, and fashion related features, and is integrated with Samsung's other products under the Samsung Galaxy brand. The series is the successor to the previous Samsung Gear watches.
The first smartwatch under this series, the Galaxy Watch , was released in August 2018. [ 1 ]
The Galaxy Watch series shares the circular form factor of the Samsung Gear S2 and S3 , as a result much of the OS features are shared between the Gear S2 and S3 and the Galaxy Watch.
For the original Galaxy Watch, the Watch Active and Active2 and the Watch3, Samsung used its in-house developed Tizen OS, which it previously used for the Samsung Gear series of watches.
With the announcement of the Galaxy Watch4 and Galaxy Watch4 Classic in August 2021, Samsung entered into a partnership with Google to work together on Wear OS [ 2 ] bringing some of the features from Samsung's Tizen with One UI Watch to Wear OS, while other features remained exclusive to Samsung's own customization to the OS.
The baseline Galaxy Watch series started as the lower cost Galaxy Watch Active line. Unlike the original Galaxy Watch and Galaxy Watch3, these watches were missing the rotating bezel. [ 3 ] The Active line put more focus on fitness and wellness. With the 4th generation, the "Active" label was dropped in favor of the form-factor becoming the base smartwatch in the series. [ 4 ] The Galaxy Watch4 was used as the base for the Galaxy Watch FE in 2024.
The Watch5 introduced a temperature sensor and added support for fast charging.
The Watch6 had an increased battery capacity and increased RAM.
The Watch7 had increased storage, an improved sensor, and support for faster charging.
The Watch5 Pro and Watch Ultra are the only watches to support GPX routes.
The Galaxy Watch Classic line supersedes the Samsung Gear S2 and S3 , inheriting the rotating bezel introduced with the Gear S2. For the first and third generation of the Galaxy Watch line, it functioned as the base smartwatch of the series. The classic line did not get a device in the second generation. However, as of the 4th generation, the original design was promoted to take on a more premium spot in the line-up. The Watch4 Classic and Watch6 Classic both continue to use the rotating bezel as an optional navigation interface. The Watch5 Pro and Watch Ultra omit the feature, both the 5th and 7th generation do not have a Classic variant of the smartwatch.
The Galaxy Watch FE ("Fan Edition" [ 17 ] ) is a cheaper smartwatch. The original Galaxy Watch FE is based on the Galaxy Watch4 with the only physical difference being the use of sapphire crystal as glass instead of the Corning Gorilla Glass DX+ used on the original Watch4. | https://en.wikipedia.org/wiki/Samsung_Galaxy_Watch_series |
The Samsung Galaxy Z Flip 6 (stylized as Samsung Galaxy Z Flip6 ) is a foldable smartphone developed by Samsung Electronics . officially announced on July 10, 2024, at the Samsung Galaxy Unpacked event in Paris, France , alongside the Samsung Galaxy Z Fold 6 , Galaxy Watch 7 Series , Samsung Galaxy Buds3 Series , and Samsung Galaxy Ring . It is the successor to the Samsung Galaxy Z Flip 5 and became available on July 31, 2024. [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ]
Compared to its predecessor, the Samsung Galaxy Z Flip 5 , the Samsung Galaxy Z Flip 6 features a more squared-off frame design. The main camera has been upgraded to 50 megapixels, and the camera rings are color-matched to the device’s body. The cover screen now supports resizable widgets, allowing multiple widgets to be displayed on a single page. [ 6 ] [ 7 ] Internally, a Vapor Chamber(VC) cooling system has been added to improve thermal management capabilities. The cover screen and back panel are protected by Corning Gorilla Glass Victus 2 , while the inner display uses Samsung’s ultra-thin flexible glass, known as UTG. The device holds an IP48 rating , making it the first foldable smartphone with certified dust protection. The frame is constructed from Armor Aluminum, without the titanium frame used in the Samsung Galaxy S24 Ultra . The device's clamshell design also enables Flex Mode, which supports split-screen interactions when partially folded. [ 8 ] [ 9 ]
The Samsung Galaxy Z Flip 6 is available in seven colors: Blue, Silver Shadow, Mint, Yellow, Crafted Black, White and Peach . Crafted Black, White, and Peach are online-exclusive variants, with Crafted black featuring a carbon fiber pattern finish. [ 10 ] [ 11 ] [ 12 ]
Flex Mode enables the device to stay partially folded at various stable angles, typically between 75 and 115 degrees. When activated, supported apps automatically adjust their interface—often displaying content on the upper half and controls or additional features on the lower half of the screen. This configuration allows users to interact with media or multitask without fully unfolding the device. [ 13 ] [ 14 ] [ 15 ]
Flex Cam builds on Flex Mode by enhancing camera functionality for hands-free use. When the device is partially folded and positioned at a stable angle—such as on a table or shelf—users can take selfies, group shots, or record videos without manually holding the phone. Example use cases include static camera setups for video recording or remote communication. Additional features include automatic framing to maintain subject alignment, voice-activated capture for touch-free operation, and live camera previews via the cover display. [ 15 ] [ 16 ]
The Galaxy Z Flip 6 features a 3.4-inch cover display that supports interactive widgets, quick reply options, and selfie previews utilizing the rear camera. Multiple widgets can now be displayed simultaneously on a single page, allowing access to functions without requiring the device to be unfolded. [ 15 ] [ 17 ] [ 18 ]
The Galaxy Z Flip 6 is equipped with the Qualcomm Snapdragon 8 Gen 3 for Galaxy processor. It features a 3.4-inch Super AMOLED cover display with an irregular shape and a 6.7-inch Dynamic AMOLED 2X panel with a variable refresh rate of up to 120 Hz. [ 19 ] [ 20 ]
The device includes 12 GB of RAM and is available with either 256 GB or 512 GB of internal storage. It does not support microSD card expansion. [ 20 ]
The Galaxy Z Flip 6 contains a 4,000 mAh dual-cell lithium polymer battery. It supports wired charging up to 25 W and wireless charging up to 15 W. [ 20 ] [ 21 ]
The Galaxy Z Flip 6 features two rear cameras: a 50 MP wide-angle lens and a 12 MP ultra-wide-angle lens. Additionally, there is a 10 MP front-facing camera on the internal display. [ 22 ]
The Galaxy Z Flip 6 included One UI 6.1.1 based on Android 14 , and software enhancements designed for foldable devices, along with support for Galaxy AI features available for flagship devices sold in 2022 and later only. [ 23 ] [ 24 ] Samsung has promised 7 generations of Android OS updates, 7 years of software updates and 7 years of security updates. [ 25 ]
As of April 2025, it is upgradable to One UI 7 , based on Android 15 . [ 26 ] [ 27 ]
Key features include :
Further details are available on the Galaxy AI Wikipedia article. | https://en.wikipedia.org/wiki/Samsung_Galaxy_Z_Flip_6 |
The Samsung Galaxy Z Fold 4 (stylized as Samsung Galaxy Z Fold4 , sold as Samsung Galaxy Fold 4 in certain territories) is a foldable smartphone that is part of the Samsung Galaxy Z series . It was announced at the August 2022 edition of Galaxy Unpacked [ 5 ] [ 6 ] alongside the Galaxy Z Flip 4 . It was released subsequently on August 25, 2022, as the successor to the Galaxy Z Fold 3 . [ 7 ] [ 8 ]
The Z Fold 4's outer display and back panel use Gorilla Glass Victus+, whilst the foldable inner display is made of Samsung's proprietary "Ultra-Thin Glass" with two protective PET plastic layers covering it, the top of which is a replaceable screen protector.
The Z Fold 4 has an IPX8 ingress protection rating for water resistance, with dust resistance not being rated. The outer frame is constructed from aluminum, marketed as 'Armor Frame' by Samsung.
The Samsung Galaxy Z Fold 4 is available in four colors: Phantom Black, Beige, Graygreen and Burgundy. [ 9 ]
The Galaxy Z Fold 4 has two screens: its 6.2-inch external cover display and its foldable 7.6-inch inner display featuring support for the S Pen Pro and the S Pen Fold Edition, with both running at 120 Hz and including support for variable refresh rate to help maximize power efficiency.
Compared to the prior generation Z Fold 3 , the inner display now has a slightly more square aspect ratio (~6:5 vs ~5:4) due to the external cover display being made moderately wider by about +3 mm; along with both it and the actual phone itself being made ever so slightly shorter. Both of these changes end up combining for a notably wider and thus closer to "traditional phone shaped" ~23.1:9 aspect ratio on the external cover display when it's folded as compared to the Fold 3's notably narrower ~24.5:9.
The device has 12 GB of RAM, and either 256 GB, 512 GB or 1 TB of UFS 3.1 flash storage, with no support for expanding the device's storage capacity via micro-SD cards.
The Z Fold 4 is powered by the Qualcomm Snapdragon 8+ Gen 1 . [ 10 ]
The device's included battery is a 4400 mAh dual-cell unit that fast charges via USB-C up to 25 W, or via wireless charging up to 15 W.
The Z Fold 4 features three rear cameras, including a 50 MP wide-angle camera, a 12 MP ultra-wide camera, and a 10 MP telephoto camera. The wide camera shares its sensor with the S22 and S22+, replacing the previous 12 MP sensor, and the telephoto camera has been upgraded from 2x to 3x optical zoom. It has two front-facing cameras, with a 10 MP camera on the cover display and a 4 MP under-display camera on the right half of the inner display which now has a less visibly apparent display covering with almost double the pixel density of the previous model. [ 11 ]
The Samsung Galaxy Z Fold 4 ships with Android 12L based One UI 4.1.1. [ 12 ] They enabled a couple of new “Labs” features for multi-window fans. With these new options enabled, users can now swipe the corner of an app inward to enable Pop-Up View. They can also swipe from the edges of the screen using two fingers to enable multi-window mode on the fly. Samsung has promised 4 Android OS upgrades (till Android 16) and 5 years of security updates (till 2027). One UI 5.0 was released on 7 November 2022. [ 13 ] Even the Galaxy Z Fold 4 is getting the stable Android 13 update in the country with firmware version F936NKSU1BVK5. These new updates also bring the November 2022 security patch to the devices to fix close to four dozen security vulnerabilities.
The One UI 6 update based on Android 14 began rolling out to all Z Fold 4 devices on 16 December 2023. [ 14 ] This was later followed by One UI 6.1, which mainly includes new AI -based features that are exclusive to this and later generations of the Galaxy Z series.
The One UI 7 update based on Android 15 began rolling out to all Z Fold 4 devices on 2 May 2025. [ 15 ] | https://en.wikipedia.org/wiki/Samsung_Galaxy_Z_Fold_4 |
The Samsung Gear 2 and Samsung Gear 2 Neo are smartwatches produced by Samsung Electronics . Unveiled on February 22, 2014 at Mobile World Congress , the Gear 2 line is a successor to the Samsung Galaxy Gear .
In comparison to the Galaxy Gear, the most significant change made to the Gear 2 line was the replacement of Android with the Samsung-developed Tizen operating system, promising improved functionality (such as Samsung's S Health software and an integrated music player) and battery life. The design of the device itself was also refreshed with the move of its camera from the watchband to the watch itself (allowing users to replace their own bands), along with the addition of an infrared blaster and optical heart rate sensor.
Its successor, the Samsung Gear S , was released on November 7, 2014.
The Gear 2 retains a similar hardware design to the original Galaxy Gear, although a Home button has been added below the screen, and the device's 2-megapixel camera was moved from the strap to the top of the watch itself, alongside a newly added infrared blaster. This particular design change allows the strap to be user-replaceable. Two models of the Gear 2 were released, the Gear 2 and Gear 2 Neo; the Gear 2 has a steel exterior and includes a camera, while the Gear 2 Neo is made from plastic and excludes the camera. They are otherwise identical. [ 2 ] [ 3 ] [ 4 ]
The device's processor was upgraded to a 1.0 GHz dual-core Exynos 3250 system-on-chip. As with the Galaxy Gear, the Gear 2 has a 1.63-inch, 320 pixel-wide square-shaped Super AMOLED touchscreen , 512 MB of RAM, and 4 GB of internal storage. [ 2 ] [ 3 ] [ 5 ] [ 6 ] An optical heart rate monitor is located on the bottom of the device. Despite having a smaller, 300 mAh battery, the Gear 2 has increased battery life over its predecessor, with Samsung rating it for 2–3 days of normal use. As with the previous model, the device itself does not contain a charging port and must be placed inside a special Micro USB -equipped charging case. [ 4 ] [ 6 ] [ 7 ]
Unlike the original Galaxy Gear, which ran Android , the Gear 2 runs Tizen , a Linux -based operating system co-developed by Samsung. The Gear 2 uses a similar user interface to the Galaxy Gear, allowing users to synchronize notifications from a host device and display them the Gear's screen when received, use Smart Relay to automatically open the relevant app for the notification on their smartphone or tablet, use S Voice for dictation and voice commands, place and answer phone calls, and locate the host phone or tablet, or vice versa with the "Find My Device" tool. Notable new apps added on the Gear 2 include the fitness app S Health, WatchOn—a remote control app which integrates with its infrared blaster, and an integrated music player which can store songs on the device's internal storage. As with the Galaxy Gear, an updated Gear Manager app is installed on the Galaxy device to coordinate communications, customize the watch and download apps from Samsung Apps . The Gear 2's Gear Manager adds the ability to customize which apps the watch displays notifications from, upload a custom wallpaper, and perform backups. [ 4 ] [ 6 ] [ 7 ]
The Gear 2 and Gear 2 Neo received mixed reviews. TechRadar considered the device to be a "much, much better attempt at making the smartwatch more relevant", with particular praise towards the streamlined design and ability to use custom watch straps, and its improved battery life, but panned the high cost of the device and its "convoluted" user interface. [ 4 ] | https://en.wikipedia.org/wiki/Samsung_Gear_2 |
The Samsung Gear Fit is a fitness wristband made by Samsung Electronics, and forms part of their Samsung Gear family of smartwatch devices. It features a curved AMOLED display. [ 2 ] Its design was developed to appeal to people interested in fitness and style. The included applications facilitate monitoring fitness activities:
Samsung stated that their Gear Fit is the "world's first" wearable device with a curved Super AMOLED touch display. It is smaller and lighter than the Gear 2 and Gear 2 Neo smartwatches, and is focused on health. It features a 1.84-inch Super AMOLED display with a 432x128 pixel resolution. The Gear Fit comes with a pedometer, heart rate monitor, and a sleep monitor.
A 210mAh battery powers the Samsung Gear Fit, which gives a typical usage of 3 to 4 days and up to 5 days with low usage. The watch body measures 23.4 mm × 57.4 mm × 11.95 mm (0.92 in × 2.26 in × 0.47 in) and it weighs 27 g (0.95 oz).
Samsung introduced the Gear Fit to the market on April 11, 2014. [ 3 ]
In June 2016, Samsung announced its new Samsung Gear Fit 2 . The activity tracker is the follow-up to the original Gear Fit, released in 2014. The new wristband has an updated design, built-in GPS, and the ability to automatically recognize certain activities, an increasingly common feature in fitness bands and watches. [ 4 ] | https://en.wikipedia.org/wiki/Samsung_Gear_Fit |
The Samsung Gear Fit2 is a fitness smartwatch made by Samsung Electronics . The product is made in China. Unveiled in June 2016, the Gear Fit2 is the successor to the Samsung Gear Fit released in 2014. [ 2 ]
Compared to the Gear Fit the new wristband has an updated design, built-in GPS , and the ability to automatically recognize different fitness activities. [ 3 ] The Gear Fit2 features a barometer and heart rate monitor . It is compatible with Android phones running OS 4.4 or later. [ 4 ]
The successor to the Gear Fit 2 is the Gear Fit2 Pro, released in 2017. It is water-resistant and has improvements related to underwater activity. [ 5 ] [ 6 ]
This mobile computing related article is a stub . You can help Wikipedia by expanding it .
This mobile computing related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Samsung_Gear_Fit_2 |
The Samsung Gear Live is an Android Wear -based smartwatch announced and released by Samsung and Google on June 25, 2014. [ 1 ] [ dead link ] It was released along with the LG G Watch as launch devices for Android Wear, a modified version of Android designed specifically for smartwatches and other wearables. [ 2 ] Gear Live is the 5th device launched in the Samsung Gear family of wearables. It is compatible with all smartphones running Android 4.3 or higher that support Bluetooth Smart .
Gear Live was initially available in the United States and Canada at US$199 on the Google Play Store, [ 3 ] and from Google's Play Store in the UK for £169. As of July 2014, the Gear Live was also available in Australia , France , Germany , India , Ireland , Italy , Japan , South Korea , and Spain . [ 4 ]
It is IP67 certified for dust and water resistance. It also has a steel exterior and a user-replaceable 22mm strap. The watch features a power button and heart rate monitor.
The notification system is based on Google Now technology, enabling it to accept, receive, transduce and ultimately process spoken commands given by the user. [ 5 ]
JR Raphael of Computerworld preferred the Gear Live's illuminated display compared to the LG G Watch , more distinctive design and the heart-rate sensor but did not like the poor outdoor visibility, the hard to use charger, awkward watch band and that it includes a redundant preinstalled stopwatch application. [ 6 ] | https://en.wikipedia.org/wiki/Samsung_Gear_Live |
Samsung Gear S is a smartwatch designed and marketed by Samsung Electronics . It was announced on August 28, 2014, as the successor to the Samsung Gear 2 and was released on November 7, 2014. [ 2 ] The smartwatch can be modified to run Android 5.1.1 [ 3 ] or Wear OS 6.0.1. [ 4 ]
Its successor, the Samsung Gear S2 , was released on October 2, 2015.
The Gear S is similar to older versions of the Samsung Galaxy Gear although it does come with some new additions. The Samsung Gear S has a curved 2.0 inch Super AMOLED screen at 360×480 pixels. It has a Quad Core 1.0 GHz processor (limited at two running cores from factory) and runs the Tizen operating system. As with the Galaxy Gear 2, the Gear S includes 512 MB RAM and 4 GB internal storage as well as a 300 mAh Li-ion battery.
Using a 3G module the watch itself is able to connect to the Internet, [ 5 ] make phone calls and send SMSs without needing a phone. It was the first wearable device to include Wi-Fi, Bluetooth and 3G connectivity. [ 6 ] | https://en.wikipedia.org/wiki/Samsung_Gear_S |
The Samsung Gear S2 is a smartwatch developed by Samsung Electronics running Samsung's Tizen operating system. It was unveiled at IFA in 2015. [ 1 ]
The Gear S2 was the first device to use eSIM technology. [ 2 ] Its successor, the Samsung Gear S3 , was released on November 18, 2016.
The watch features a rotating bezel user interface and an IP68 rating for water resistance up to 1.5 meters deep in 30 minutes. It is compatible with 20mm width watch straps. [ 3 ] [ 4 ] It has a Super AMOLED display with a resolution of 360 x 360 pixels and a screen size of 1.2 inches. The watch has a dual-core Exynos processor running at 1 GHz. Samsung Pay can be used through NFC payment terminals.
This Samsung mobile phone-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Samsung_Gear_S2 |
The Samsung Gear S3 is a Tizen -based circular smartwatch developed by Samsung Electronics . It was released on 18 November 2016. [ 1 ]
There are two models of the Gear S3, Classic and Frontier. The Classic has a silver watch case and black leather band, while the Frontier has a black watch case and rubber band. Both are rated IP68 (water resistant) and have GPS and heart rate monitor sensors. One notable feature is that the bezel ring rotates as part of the user interface , although users can also navigate by swiping the screen and/or using the two buttons on the side. [ 2 ]
The Gear S3's successor, the Samsung Galaxy Watch , was released 9 August 2018.
Always-on display, Corning Gorilla Glass SR+
NFC, MST , GPS/Glonass
NFC , MST, A-GPS / Glonass
NFC, MST, GPS/Glonass
NFC , MST, A-GPS / Glonass
The "LTE" models are further divided into sub-models depending on the target country and Service Provider cellular infrastructure available.
This Samsung mobile phone-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Samsung_Gear_S3 |
The Samsung Gear Sport is a smartwatch developed by Samsung Electronics . The Gear Sport was released at Samsung Galaxy Unpacked in 2017. [ 1 ]
This Samsung mobile phone-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Samsung_Gear_Sport |
Samsung Knox (stylized as SΛMSUNG Knox ) is a proprietary security and management framework pre-installed on most Samsung mobile devices. Its primary purpose is to provide organizations with a toolset for managing work devices, such as employee mobile phones or interactive kiosks . [ 2 ] Samsung Galaxy hardware, as well as software such as Secure Folder and Samsung Wallet , make use of the Knox framework. [ 3 ] [ 4 ]
Knox's features fall within three categories: data security, device manageability, and VPN capability. [ 5 ] Knox also provides web-based services for organizations to manage their devices. Organizations can customize their managed mobile devices by configuring various functions, including pre-loaded applications, settings, boot-up animations, home screens , and lock screens . [ 6 ]
Knox provides more granular control over the standard work profile to manage capabilities found only on Samsung devices. [ 7 ] As of December 2020, organizations can use specific Samsung mobile device cameras as barcode scanners , using Knox services to capture and analyze the data. [ 8 ]
Samsung Knox provides hardware and software security features that allow business and personal content to coexist on the same device. Knox integrates web services to assist organizations in managing fleets of mobile devices, which allows IT administrators to register new devices, identify a unified endpoint management (UEM) system, define the organizational rules that govern the use of devices, and upgrade device firmware over-the-air. [ 9 ] Developers can integrate these features with their applications using Knox SDKs and REST APIs . [ 10 ]
Samsung Knox provides the following web-based services for organizations:
Most services are registered and accessed through the Samsung Knox web consoles, [ 15 ] with some accessed through the Samsung Knox SDK. [ 16 ]
Knox Capture uses a Samsung mobile device’s camera to capture all major barcode symbologies like UPC, Code 39, EAN, and QR. Through a web console, IT admins can manage the input, formatting, and output configuration of scanned barcode data, and associate a device app (for example, a web browser for QR data). [ 17 ]
Knox Asset Intelligence helps organizations improve the management, productivity, and lifecycle of mobile devices. Through a web console, IT admins can monitor device battery management, app usage insights, comprehensive device tracking, and detailed Wi-Fi analytics. [ 18 ]
When Samsung Knox debuted with the Galaxy Note 3 in 2013, it included a proprietary container feature that stored security-sensitive applications and data inside a protected execution environment. [ 19 ] Device users could switch between personal and business applications by tapping a Knox icon in the lower-left corner of the device screen. [ 20 ] The proprietary container, later called the Knox Workspace, was managed by organizations through a UEM system. [ 21 ]
Samsung then spun off consumer versions of the container feature, which did not require a UEM system to manage. These consumer versions included Personal Knox, later called My Knox starting in 2014. My Knox was replaced by Secure Folder in 2017. [ 22 ]
In 2018, Samsung partnered with Google to use its Android work profile to secure applications and data, and in 2019 deprecated the Knox Workspace container. [ 23 ] Samsung continues to pre-install the Secure Folder on most flagship mobile devices, but consumers must enable it for use. [ 24 ]
The Samsung RKP feature tracks kernel changes in real-time and prevents the phone from booting, as well as displaying a warning message about using "Unsecured" Samsung devices. [ 25 ] This feature is analogous to Android dm-verity /AVB and requires a signed bootloader . [ 26 ]
Although Android phones are already protected from malicious code or exploits by SE for Android and other features, Samsung Knox provides periodic updates that check for patches to further protect the system. [ 27 ]
During Secure Boot, Samsung runs a pre-boot environment to check for a signature match on all operating system (OS) elements before booting in the main kernel. If an unauthorized change is detected, the e-fuse is tripped and the system's status changes from "Official" to "Custom". [ 28 ]
Several other features that facilitate enterprise use are incorporated in Samsung Knox, including Samsung KMS (SKMS) for eSE NFC services, Mobile device management (MDM), Knox Certificate Management (CEP), Single Sign-On (SSO), One Time Password (OTP), SIM PIN Management, Firmware-Over-The-Air (FOTA) [ 29 ] and Virtual Private Network (VPN). [ 30 ] [ 31 ] [ 32 ] [ 33 ]
Samsung has patched the kernel to prevent root access from being granted to apps even after rooting was successful since the release of Android Oreo . This patch prevents unauthorized apps from changing the system and deters rooting. [ 34 ]
Knox includes built-in hardware security features ARM TrustZone (a technology similar to TPM ) and a bootloader ROM . [ 35 ] Knox Verified Boot monitors and protects the phone during the booting process, along with Knox security built at a hardware level (introduced in Knox 3.3). [ 36 ]
Samsung Knox devices use an e-fuse to indicate whether or not an "untrusted" (non-Samsung) boot path has ever been run. The e-Fuse will be set in any of the following cases:
On Galaxy Book devices starting with the Galaxy Book 4, upgrading from one Windows version to another (from 22H2 to 23H2) will not set the e-Fuse, but upgrading to a higher edition (from Home to Pro) will [ citation needed ] .
When set, the text "Set warranty bit: <reason>" appears. Once the e-fuse is set, a device can no longer create a Knox Workspace container or access the data previously stored in an existing Knox Workspace. [ 37 ] In the United States, this information may be used by Samsung to deny warranty service to devices that have been modified in this manner. [ 38 ] Voiding consumer warranties in this manner may be prohibited by the Magnuson–Moss Warranty Act of 1975, at least in cases where the phone's problem is not directly caused by rooting. [ 39 ] In addition to voiding the warranty, tripping the e-fuse also prevents some Samsung-specific apps from running, such as Secure Folder, Samsung Pay , Samsung Health , and Samsung Internet 's secret mode (as well as certain Samsung apps preloaded on Galaxy Books). [ citation needed ] For some older versions of Knox, it may be possible to clear the e-fuse by flashing a custom firmware. [ 40 ]
Options to manage Samsung DeX were added in Knox 3.3 to allow or restrict access using the Knox platform for added control and security. [ 41 ]
Knox's TrustZone-based Integrity Measurement Architecture (TIMA) allows storage of keys in the container for certificate signing using the TrustZone hardware platform. [ 42 ]
In June 2014, the Defense Information Systems Agency 's (DISA) list of approved products for sensitive but unclassified use included five Samsung devices. [ 43 ]
In October 2014, a security researcher discovered that Samsung Knox stores PINs in plain text rather than storing salted and hashed PINs and processing them by obfuscated code . [ 44 ]
In October 2014, the National Security Agency (NSA) approved Samsung Galaxy devices for use in a program for quickly deploying commercially available technologies. Approved products include Galaxy S4 , Galaxy S5 , Galaxy S6 , Galaxy S7 , Galaxy Note 3 , and Galaxy Note 10.1 2014 . [ 43 ]
In May 2016, Israeli researchers Uri Kanonov and Avishai Wool found three vulnerabilities in specific versions of Knox. [ 45 ]
In December 2017, Knox received "strong" ratings in 25 of 28 categories in a Gartner publication comparing device security strength of various platforms. [ 46 ] | https://en.wikipedia.org/wiki/Samsung_Knox |
Samuel Alexander OM FBA (6 January 1859 – 13 September 1938) was an Australian-born British philosopher. He was the first Jewish fellow of an Oxbridge college. [ 2 ] He is now best known as an advocate of emergentism in biology. [ 3 ]
He was born into a Jewish family at 436 George Street, Sydney , Australia, the third son of Samuel Alexander, a prosperous saddler , and Eliza née Sloman. His father died around the time he was born, of tuberculosis. Eliza moved the family to St Kilda, Victoria in 1863 or 1864, and Alexander was tutored, and placed at a private school. In 1871, he was sent to Wesley College, Melbourne , then under the headmastership of Martin Howy Irving . [ 2 ] [ 4 ] [ 5 ] [ 6 ]
Alexander matriculated at the University of Melbourne on 22 March 1875. He completed the first two years with distinction, but then left without taking a degree. [ 2 ]
In May 1877, Alexander sailed for England in an attempt to win a scholarship at Oxford or Cambridge . He was successful at Balliol College, Oxford , and matriculated there on 28 January 1878. He graduated B.A. in 1881, was elected a Fellow of Lincoln College in 1882, and graduated M.A. in 1884. [ 2 ] [ 7 ] He remained as philosophy tutor at Lincoln College to 1893. It was during this period that he developed his interest in psychology , then a neglected subject. He travelled on the continent of Europe, and in the winter of 1890–91 was in Germany working on experimental psychology at the laboratory of Hugo Münsterberg at Freiburg . [ 2 ]
Alexander for much of his life was deaf, which acted as a handicap. [ 5 ] For some time, he wanted to obtain a professorship . He made three unsuccessful attempts before he was appointed at Owens College, Manchester in 1893. Among his colleagues there was the educational theorist Catherine Isabella Dodd , whom he admired. [ 8 ] Another educationalist he found impressive was Esther Lawrence , a cousin. [ 9 ]
Robert Mackintosh (1858–1933) owed his appointment as lecturer in 1904 to the new Manchester theological faculty in 1904 to Alexander, he believed. [ 10 ] Alexander introduced experimental psychology at Manchester in 1907, in unorthodox fashion, with the appointment of Tom Pear (1886–1972), later a professor. Pear was recruited while still an undergraduate, but was backed by Charles Sherrington , who had brought William George Smith as a lecturer to the University of Liverpool in 1905. [ 11 ] He invited John Macmurray to be a lecturer in the philosophy department in 1919. [ 12 ]
Alexander was president of the Aristotelian Society from 1908 to 1911, and again from 1936 to 1937. [ 13 ] In 1913, he was made a Fellow of the British Academy . [ 1 ] R. G. Collingwood met Alexander in 1917, when both were working for the United Kingdom , and they kept in touch on philosophy for the rest of Alexander's life. [ 14 ] Collingwood later contended that Alexander had "philosophical genius of very high order". [ 15 ] Alexander influenced A. N. Whitehead , and mentored others who went on to become major figures in 20th-century British philosophy. One such was John Anderson . [ 16 ]
In 1924 Alexander retired from his chair, and was succeeded by John Leofric Stocks . [ 17 ]
He was given the Hon. LLD of St Andrews in 1905, and in later years he received Hon. Litt. D. degrees from Durham, Liverpool , Oxford and Cambridge. [ 6 ] [ 13 ]
In 1924, Alexander sat for the sculptor Jacob Epstein , who made two copies of a bust. One copy went to the Ben Uri Gallery & Museum , and the other to the University of Manchester . [ 18 ] He was Herbert Spencer lecturer at Oxford in 1927, and in 1930 the Order of Merit was conferred on him, the first to a native of Australia. [ 13 ] [ 5 ]
Alexander died on 13 September 1938. He was unmarried and his ashes lie in Manchester Southern cemetery (British Jewish Reform Congregation section). [ 2 ] He left money to the University of Jerusalem and the University of Manchester. John Laird , his literary executor, edited Philosophical and Literary Pieces (1939). [ 6 ] His papers were left to the John Rylands Library . [ 1 ]
The building formerly known as Humanities Lime Grove at the University of Manchester was renamed the Samuel Alexander Building, in 2007. [ 19 ] [ 20 ] A theatre at Monash University , Melbourne, and a conference room at Wesley College, Melbourne are also named for him. [ 5 ]
Alexander contributed articles on philosophical subjects to Mind , the Proceedings of the Aristotelian Society , and the International Journal of Ethics . In 1887, he won the Green moral philosophy prize with an essay on the subject "In what direction does Moral Philosophy seem to you to admit or require advance?" It was the basis of his volume Moral Order and Progress , which was published in 1889 and went into its third edition in 1899. Alexander credited A. C. Bradley with introducing him to ethics, and his brother F. H. Bradley helped him with the book. He was influenced by T. H. Green , in whose memory the prize had been set up, but diverged from his views in pursuing evolutionary ethics . [ 21 ]
Alexander was appointed Gifford lecturer at Glasgow in 1915, and delivered his lectures in the winters of 1917 and 1918. They drew on preliminary papers he had written from 1908 onwards. These materials he developed into his major work Space, Time, and Deity , published in two volumes in 1920. [ 2 ] John Laird called it "the boldest adventure in detailed speculative metaphysics attempted in so grand a manner by any English writer between 1655 and 1920". [ 22 ] His Arthur Davis Memorial Lecture on Spinoza and Time , in the nature of an annexe to Space, Time, and Deity , was published in 1921. [ 2 ]
In 1933, Alexander published Beauty and Other Forms of Value , mainly an essay in aesthetics . It incorporated passages from papers that had appeared in the previous ten years. Compared to his systematic work, it was rather closer to the mainstream of British thought, and was praised highly by R. G. Collingwood. [ 2 ]
Two key concepts for Alexander are those of an " emergent quality " and the idea of emergent evolution :
As existents within Space-Time , minds enter into various relations of a perfectly general character with other things and with one another. These account for the familiar features of mental life : knowing , freedom , values and the like. In the hierarchy of qualities the next higher quality to the highest attained is deity . God is the whole universe engaged in process towards the emergence of this new quality, and religion is the sentiment in us that we are drawn towards him, and caught in the movement of the world to a higher level of existence.
His idea was to start with space and time, each of which he regarded as inconceivable without the other, in fact mutually equivalent. His thinking, as he said, originated in Instinct and Experience (1912) by C. Lloyd Morgan ; who went on in 1922 to give an exposition of emergent properties. [ 23 ] Pure spacetime emerges, through a process Alexander describes simply as "motion", the stuff and matter that make up our material world:
Space-Time, the universe in its primordial form, is the stuff out of which all existents are made. It is Space-Time with the characters which we have found it to reveal to experience. But it has no 'quality' save that of being spatio-temporal or motion.
Motion is not a succession of point-instants, but rather a point-instant is the limiting case of a motion.
Point-instants are real but their separateness from one another is conceptual. They are in fact the elements of motion and in their reality are inseparable from the universe of motion; they are elements in a continuum.
Time makes Space distinct and Space makes Time distinct... Space or Time, may be regarded as supplying the element of diversity to the element of identity supplied by the other.
Alexander absolutizes spacetime, and even speaks of it as an "Entity|stuff" of which things are made. At the same time he also says that spacetime can be called "Motions" – not motion in the singular, but complexes of motions with kaleidoscopic changes within a continuum. In other words, for Alexander motion is primitive, and space and time are defined through relations between motions.
In Space, Time, and Deity Alexander held that an object may be before a consciousness , but is not in it; consciousness of an object is not the same as consciousness of one's consciousness of the object . For example, an object such as a chair may be apprehended by a consciousness, but the chair is not located within that consciousness; and, the contemplation of the chair is distinct from thinking about the act of contemplating the chair. Further, since the contemplation of an object is itself an action , in Alexander's view it cannot be "contemplated", but only subjectively experienced, or "enjoyed".
Alexander asked the question:
How far a science of order could be founded on this bare conception of ordered parts of Space-Time I do not know. But at any rate the more comprehensive theorems of speculative mathematics at the present time do not thus proceed. They appear to use the conception of Space and Time not as being stuffs, as we have taken them to be, within which there are relations of the parts of Space and Time themselves, but as relational in the sense that they are relations between things or entities. This is the antithesis between absolute and relational
Alexander's views have been described as panentheistic . [ 24 ]
A change in Alexander's home life occurred in 1902 when the whole of his family—his mother, an aunt, two elder brothers and his sister—came from Australia to live with him. [ 5 ] His sister became his hostess and on Wednesday evenings there were informal social gatherings. [ 6 ]
Alexander was an "unofficial godfather" to writer Naomi Mitchison née Haldane, born in 1897. He took an interest in her studies, and wrote her long letters. Mitchison devoted a chapter in her autobiographical work You May Well Ask to Alexander, recounting affectionate anecdotes and quoting extensively from his letters. [ 25 ] | https://en.wikipedia.org/wiki/Samuel_Alexander |
Samuel Francis (Frank) Boys (20 December 1911 – 16 October 1972) was a British theoretical chemist . [ 1 ] [ 4 ] [ 5 ]
Boys was born in Pudsey , Yorkshire, England. He was educated at the Grammar School in Pudsey and then at Imperial College London , whence he graduated in Chemistry in 1932. He then embarked on postgraduate study at Trinity College, Cambridge , supervised first by Martin Lowry , [ 6 ] and then, after Lowry's death in 1936, by John Lennard-Jones . He awarded a PhD in 1937 from Cambridge, for a thesis on "The Quantum Theory of Optical Rotation". [ 7 ]
In 1938, Boys was appointed an Assistant Lecturer in Mathematical Physics at Queen's University Belfast . He spent the whole of the Second World War working on explosives research with the Ministry of Supply at the Royal Arsenal , Woolwich , with Lennard-Jones as his supervisor. After the war, Boys accepted an ICI Fellowship at Imperial College, London. In 1949, he was appointed to a Lectureship in theoretical chemistry at the University of Cambridge. He remained at Cambridge until his death. He was only elected to a Cambridge College Fellowship at University College, now Wolfson College, Cambridge , shortly before his death.
Boys is best known for the introduction of Gaussian orbitals into ab initio quantum chemistry . [ 8 ] [ 9 ] Almost all basis sets used in computational chemistry now employ these orbitals. [ 10 ] Frank Boys was also one of the first scientists to use digital computers for calculations on polyatomic molecules.
An International Conference, entitled "Molecular Quantum Mechanics: Methods and Applications" was held in memory of S. Francis Boys and in honour of Isaiah Shavitt in September 1995 at St Catharine's College, Cambridge . [ 11 ] [ 9 ]
Boys was a member of the International Academy of Quantum Molecular Science . He was elected a Fellow of the Royal Society (FRS) in 1972 , a few months before his death. [ 1 ] | https://en.wikipedia.org/wiki/Samuel_Francis_Boys |
Samuel H. Wood is a scientist and fertility specialist. In 2008, he became the first man to clone himself, donating his own DNA via somatic cell nuclear transfer (SCNT) to produce mature human embryos that were his clones.
Wood completed undergraduate studies in psychology at Loma Linda University in 1979. His graduate training includes a M.A. in psychology from the University of Richmond (1980), an M.D. (1985) and a Ph.D. (1986) from Medical College of Virginia , and an MBA from San Diego State University (1997). [ 1 ]
Wood's early scholarship laid the foundation for his future scientific endeavors, beginning with an initial focus on DNA . While attending the Medical College of Virginia , Wood researched isolating a DNA nuclear matrix of HeLa cells using a poly(dT) template. He and his colleagues discovered that HeLa cell primase in these cells is in a bound form and they determined the presence of multiple forms of polymerase α. [ 2 ] Wood further studied DNA, in the form of nucleoids, while in his clinical residency in Obstetrics and Gynecology at the University of North Carolina at Chapel Hill . The properties of two types of "subnuclear systems" (preparations of non-DNased-digested nuclei vs. DNased-digested nuclei) were differentiated along with their respective ability to retain elongation in response to increasing concentrations of salt. [ 3 ]
Wood then turned his attention to treating premenstrual syndrome (PMS) as well as improving pregnancy rates when using donated eggs. During a fellowship in reproductive endocrinology and infertility , Wood studied the usefulness of fluoxetine (tradename Prozac or Sarafem) for patients experiencing severe PMS. He and his research team found this medication significantly reduced behavioral and physical symptoms during the luteal phase without suffering significant side effects or treatment complications. [ 4 ] The collaborators subsequently investigated the efficacy of RU 486 (commonly referred to as "the abortion pill") in treating PMS but found symptoms experienced with administration of low-dose RU 486 to be virtually indistinguishable from subjects receiving a placebo . [ 5 ]
Upon opening a private practice, Wood continued to expand the knowledge base in the field of infertility. He and his team analyzed data over a 5-year period for both fresh and frozen egg donation cases with and without use of a gestational surrogate . They found a previously undiscovered "uterine factor" to consider when egg donation resulted in repeated pregnancy failure. Furthermore, they found successful implantation rates were significantly higher for surrogates in both fresh and frozen embryo transfers. [ 6 ] Additionally, surrogates showed a significantly higher pregnancy rate following frozen embryo transfers than their non-surrogate counterparts.
Wood entered the arena of stem cell research shortly after the first published study of nuclear transfer stem cells (NTSC), also known as human therapeutic cloning, was withdrawn when the principal author's claims were called into question due to falsified data and ethical deviation from scientific research standards. [ 7 ] Australian scientist Andrew French , best known for his work with somatic cell nuclear transfer (SCNT) in the mammalian reproduction process, co-investigated with Wood and French's Australian colleague, Alan Trounson. Based on meticulous mammalian study review, the researchers concluded that the rigorous procedures developed for mammalian reproduction held promise for practical application in human embryonic stem cell (hESC) line production. Furthermore, they specifically proposed hESC research should steer away from attempting to produce viable offspring, focusing efforts on the use of cloned embryos as a viable source for deriving stem cell lines instead. [ 8 ]
In 2008, Wood created embryo copies of himself by placing his skin cells in a woman's egg, marking the first time anyone had done so with adult skin cells. [ 9 ] [ 10 ] [ 11 ] The five cloned embryos were later destroyed, [ 10 ] [ 11 ] [ 12 ] In January 2008, Wood and Andrew French, Stemagen's chief scientific officer in California , announced that they had successfully created the first five mature human embryos using DNA from adult skin cells, aiming to provide a less-controversial source of viable embryonic stem cells . [ 9 ] Dr. Wood and a colleague donated skin cells and the DNA from those cells was transferred into human eggs. It is not clear if the embryos produced would have been capable of further development, but Dr. Wood stated that if that were possible, using the technology for reproductive cloning would be both unethical and illegal. The five cloned embryos, created in Stemagen Corporation lab in La Jolla , were later destroyed. [ 12 ]
Wood and five other researchers published their findings in the online research journal Stem Cells in an article entitled Development of Human cloned Blastocyst Following Somatic Cell Nuclear Transfer (SCNT) with Adult Fibroblasts. [ 9 ] [ 13 ] | https://en.wikipedia.org/wiki/Samuel_H._Wood |
In mathematics, the Samuelson–Berkowitz algorithm efficiently computes the characteristic polynomial of an n × n {\displaystyle n\times n} matrix whose entries may be elements of any unital commutative ring . Unlike the Faddeev–LeVerrier algorithm , it performs no divisions, so may be applied to a wider range of algebraic structures.
The Samuelson–Berkowitz algorithm applied to a matrix A {\displaystyle A} produces a vector whose entries are the coefficient of the characteristic polynomial of A {\displaystyle A} . It computes this coefficients vector recursively as the product of a Toeplitz matrix and the coefficients vector an ( n − 1 ) × ( n − 1 ) {\displaystyle (n-1)\times (n-1)} principal submatrix .
Let A 0 {\displaystyle A_{0}} be an n × n {\displaystyle n\times n} matrix partitioned so that
The first principal submatrix of A 0 {\displaystyle A_{0}} is the ( n − 1 ) × ( n − 1 ) {\displaystyle (n-1)\times (n-1)} matrix A 1 {\displaystyle A_{1}} . Associate with A 0 {\displaystyle A_{0}} the ( n + 1 ) × n {\displaystyle (n+1)\times n} Toeplitz matrix T 0 {\displaystyle T_{0}} defined by
if A 0 {\displaystyle A_{0}} is 1 × 1 {\displaystyle 1\times 1} ,
if A 0 {\displaystyle A_{0}} is 2 × 2 {\displaystyle 2\times 2} ,
and in general
That is, all super diagonals of T 0 {\displaystyle T_{0}} consist of zeros, the main diagonal consists of ones, the first subdiagonal consists of − a 1 , 1 {\displaystyle -a_{1,1}} and the k {\displaystyle k} th subdiagonal
consists of − R A 1 k − 2 C {\displaystyle -RA_{1}^{k-2}C} .
The algorithm is then applied recursively to A 1 {\displaystyle A_{1}} , producing the Toeplitz matrix T 1 {\displaystyle T_{1}} times the characteristic polynomial of A 2 {\displaystyle A_{2}} , etc. Finally, the characteristic polynomial of the 1 × 1 {\displaystyle 1\times 1} matrix A n − 1 {\displaystyle A_{n-1}} is simply T n − 1 {\displaystyle T_{n-1}} . The Samuelson–Berkowitz algorithm then states that the vector v {\displaystyle v} defined by
contains the coefficients of the characteristic polynomial of A 0 {\displaystyle A_{0}} .
Because each of the T i {\displaystyle T_{i}} may be computed independently, the algorithm is highly parallelizable . | https://en.wikipedia.org/wiki/Samuelson–Berkowitz_algorithm |
The San Jose BioCenter is a business incubator formed as a university foundation in 2004 and focused on the initiation and development of technology companies, with an emphasis on the life sciences industry. [ 1 ] [ 2 ] The BioCenter emerged from San Jose State University in an effort to revitalize an industrial area of San Jose, California . [ 1 ] As of 2012 [update] , the BioCenter had thirty-five member (assisted) companies and twelve affiliate (supporting) companies. [ 1 ] [ 2 ] In addition to office space, the BioCenter provides wet laboratory facilities to member companies. [ 1 ] [ 3 ]
This article about an organization in the United States is a stub . You can help Wikipedia by expanding it .
This San Jose, California -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/San_Jose_BioCenter |
The San Juan–Chama Project is a U.S. Bureau of Reclamation interbasin water transfer project located in the states of New Mexico and Colorado in the United States . The project consists of a series of tunnels and diversions that take water from the drainage basin of the San Juan River – a tributary of the Colorado River – to supplement water resources in the Rio Grande watershed. The project furnishes water for irrigation and municipal water supply to cities along the Rio Grande including Albuquerque and Santa Fe .
Most major agricultural and urban areas in New Mexico today lie along the narrow corridor of the Rio Grande as it cuts across the center of this predominantly desert state. Spanish settlers arrived in the area in the late 1500s, followed by Mexican and American settlers in the 18th and 19th centuries, building large irrigation systems and diversion dams to allow agricultural production in the arid region. In the early 1920s, water supply in the Rio Grande basin was already severely stressed, and studies were conducted as to the feasibility of procuring additional water by transbasin diversion from tributaries of the San Juan River. [ 1 ]
The 1933–1934 Bunger Survey studied potential locations for diversions and storage reservoirs, and in 1939, the Rio Grande Compact was signed, dividing Rio Grande waters between Colorado, New Mexico, and Texas including allocations from a potential future diversion from the San Juan basin. [ 2 ] When the Upper Colorado River Basin Compact was established in 1948, it also included provisions for the tentative diversion project under its water allotment to New Mexico. [ 1 ] In the 1950s, post- World War II population growth in central New Mexico put even larger strains on the Rio Grande's water, and the need for a transbasin water project rose because water supplies in the area quickly became overallocated. [ 2 ]
Studies for the project continued through the early 1950s, but actual implementation languished until 1962 when Congress amended the Colorado River Storage Act of 1956 , allowing the diversion of part of New Mexico's share of Colorado River basin waters into the Rio Grande basin. [ 3 ] The diversions proposed were for 235,000 acre⋅ft (0.290 km 3 ) per year from three tributaries of the San Juan River in Colorado: the Rio Blanco , Navajo and Little Navajo Rivers, to the headwaters of the Rio Chama , a major tributary of the Rio Grande. The project would be constructed in two phases. [ 1 ] [ 2 ] However, Reclamation ran into difficulties because the Navajo Nation asserted rights to about 900,000 acre⋅ft (1.1 km 3 ) of water from the San Juan River, which runs through their traditional lands. Resultantly, only the first phase of the project was ever constructed, delivering just under 47% of the original amount proposed by Reclamation. [ 2 ] [ 4 ]
On December 19, 1964, construction began on the Azotea Tunnel, the main water tunnel for the project, running from the Navajo River south to Azotea Creek in the Rio Chama watershed. Work started on the Oso and Little Oso tunnels in February 1966, and construction on the Blanco Tunnel began in March of the same year. In 1967, an enlargement of the outlets of existing El Vado Dam to accommodate increased flows from the diversion project was completed, and construction began on Heron Dam, which would impound the project's main storage reservoir. [ 1 ] Azotea Tunnel was holed through and construction was finished on the project's three diversion dams in 1970. Heron Dam was completed the next year. Nambe Falls Dam, completed in 1976, was the last part of the project to be built. The dam was the only one built of a series of small independent irrigation units originally proposed under the project to serve Native American lands. In 1978, Reclamation announced the completion of the San Juan–Chama Project. [ 2 ]
The San Juan–Chama Project taps the water of the Rio Blanco, Navajo, and Little Navajo Rivers via a series of small diversion dams , tunnels, and siphons. Blanco Diversion Dam, with a diversion capacity of 520 cu ft/s (15 m 3 /s), sends water into the Blanco Feeder Conduit, which connects to the 8.64-mile (13.90 km)-long Blanco Tunnel and flows south towards the Little Navajo River. The water passes underneath the river via the Little Oso Siphon and connects to the Oso Tunnel. Just upstream from the siphon, Little Oso Diversion Dam sends up to 150 cu ft/s (4.2 m 3 /s) of water through the Little Oso Feeder Conduit, which also empties into the Oso Tunnel. [ 1 ]
Oso Tunnel, with a capacity of 650 cu ft/s (18 m 3 /s), travels 5.05 miles (8.13 km) south to the Navajo River, which it passes under via the Oso Siphon. Oso Diversion Dam on the Navajo diverts additional water into the Oso Feeder Conduit, which joins with water from the Oso Tunnel and Siphon to form the Azotea Tunnel. The Azotea Tunnel, which has a capacity of 950 cu ft/s (27 m 3 /s), runs south for 12.8 miles (20.6 km), passing under the Continental Divide . The tunnel terminates at Azotea Creek, a tributary of Willow Creek, which is in turn a tributary of the Rio Chama. The lower portion of Azotea Creek has been channelized to mitigate erosion from the higher flows. [ 1 ]
The main storage facility for the project is Heron Lake , a reservoir formed by Heron Dam on Willow Creek about 8 miles (13 km) downstream of the terminus of Azotea Tunnel and 20 miles (32 km) southwest of Chama, New Mexico . The reservoir has a capacity of 401,320 acre⋅ft (0.49502 km 3 ) and has a surface area of 5,950 acres (2,410 ha). Heron Dam is an earthfill dam 269 feet (82 m) high and 1,220 feet (370 m) long, standing 249.1 feet (75.9 m) above the streambed. Heron Lake receives water from a catchment of 193 sq mi (500 km 2 ), which has been augmented to over three times this size by the San Juan–Chama diversions. [ 1 ] [ 5 ]
Nambe Falls Dam is located about 15 miles (24 km) north of Santa Fe on the Rio Nambe, a tributary of the Rio Grande. The dam and reservoir are functionally independent from the other facilities of the San Juan–Chama Project. The curved earthfill dam forms Nambe Falls Lake, which has a capacity of 2,023 acre⋅ft (2,495,000 m 3 ) and controls runoff from a catchment of 35 sq mi (91 km 2 ). Its main purpose is to provide irrigation water for about 2,800 acres (1,100 ha) in the Pojoaque Valley, which is situated west and downstream of the dam. [ 6 ]
Each year, a minimum of 86,210 acre⋅ft (0.10634 km 3 ) of San Juan–Chama water is allocated as follows. Because annual diversions average about 110,000 acre⋅ft (0.14 km 3 ), there is usually a surplus available for other uses along the river. About 75% of the water serves municipal and industrial uses; the remaining fourth furnishes irrigation supplies to approximately 92,500 acres (37,400 ha) of land along the Rio Grande and Rio Nambe. Surplus water is also used to maintain a permanent pool at the Cochiti Lake flood-control reservoir on the Rio Grande. | https://en.wikipedia.org/wiki/San_Juan–Chama_Project |
In mycology , a sanctioned name is a name that was adopted (but not necessarily coined) in certain works of Christiaan Hendrik Persoon or Elias Magnus Fries , which are considered major points in fungal taxonomy.
Sanctioned names are those, regardless of their authorship, that were used by Persoon in his Synopsis Methodica Fungorum (1801) for rusts , smuts and gasteromycetes , and in Fries's Systema Mycologicum (three volumes, published 1821–1832) and Elenchus fungorum for all other fungi. [ 1 ]
A sanctioned name, as defined under article 15 of the International Code of Nomenclature for algae, fungi, and plants (previously, the International Code of Botanical Nomenclature ) is automatically treated as if conserved against all earlier synonyms or homonyms . [ 2 ] It can still, however, be conserved or rejected normally.
Because of the imprecision associated with assigning starting dates for fungi sanctioned in Fries' three Systema volumes, the Stockholm 1950 International Botanical Congress defined arbitrary or actual publication dates for the starting points to improve the stability of nomenclature. These dates were 1 May 1753 for Species Plantarum (vascular plants), 31 December 1801 for Synopsis Methodica Fungorum , 31 December 1820 for Flora der Vorweldt (fossil plants), and 1 January 1821 for the first volume of Systema . Because fungi defined in the second and third volumes lacked a starting-point book for reference, the Congress declared that these species, in addition to species defined in Fries' 1828 Elenchus Fungorum (a two-volume supplement to his System ), had "privileged status". According to Korf, [ 1 ] the term "sanctioned" was first used to indicate these privileged names by the Dutch mycologist Marinus Anton Donk in 1961. [ 3 ]
In 1982, changes in the International Code for Botanical Nomenclature (the Sydney Code) restored Linnaeus ' 1753 Species Plantarum as the starting point for fungal nomenclature; however, protected status was given to all names adopted by Persoon in his 1801 Synopsis , and by Fries in both the Systema and the Elenchus . [ 1 ] [ 4 ] Soon after, in 1983, Richard P. Korf proposed the now widely accepted "colon-author indication", whereby sanctioned names are indicated by including ": Pers." or ": Fr." when fully citing the species author. [ 5 ] Formal approval of this convention was abolished in the 2018 revision to the Fungi chapter of the code. [ 6 ] | https://en.wikipedia.org/wiki/Sanctioned_name |
The species name sanctus ( Latin for "sacred") occurs in several binomial names in the taxonomy of life . Examples include: | https://en.wikipedia.org/wiki/Sanctus_(species) |
A sand bath is a common piece of laboratory equipment made from a container filled with heated sand . It is used to evenly heat another container, most often during a chemical reaction .
A sand bath is most commonly used in conjunction with a hot plate or heating mantle . A beaker is filled with sand or metal pellets (called shot ) and is placed on the plate or mantle. The reaction vessel is then partially covered by sand or pellets. The sand or shot then conducts the heat from the plate to all sides of the reaction vessel.
This technique allows a reaction vessel to be heated throughout with minimal stirring, as opposed to heating the bottom of the vessel and waiting for convection to heat the remainder, cutting down on both the duration of the reaction and the possibility of side reactions that may occur at higher temperatures.
A variation on this theme is the water bath in which the sand is replaced with water. It can be used to keep a reaction vessel at the temperature of boiling water until all water is evaporated (see Standard enthalpy change of vaporization ).
Sand baths are one of the oldest known pieces of laboratory equipment, having been used by the alchemists . In Arabic alchemy , a sand bath was known as a qadr . [ 1 ] In Latin alchemy, a sand bath was called balneum siccum , balneum cineritium , or balneum arenosum . | https://en.wikipedia.org/wiki/Sand_bath |
Sand dune ecology describes the biological and physico-chemical interactions that are a characteristic of sand dunes .
Sand dune systems are excellent places for biodiversity, partly because they are not very productive for agriculture, and partly because disturbed, stressful, and stable habitats are present in proximity to each other. Many of them are protected as nature reserves, and some are parts of larger conservation areas, incorporating other coastal habitats like salt marshes , mud flats, grasslands, scrub, and woodland.
Sand dunes provide a range of habitats for a range of unusual, interesting and characteristic plants that can cope with disturbed habitats. In the UK these may include restharrow Ononis repens , sand spurge Euphorbia arenaria and ragwort Senecio vulgaris - such plants are termed ruderals.
Other very specialised plants are adapted to the accretion of sand, surviving the continual burial of their shoots by sending up very rapid vertical growth. Marram grass, Ammophila arenaria specialises in this, and is largely responsible for the formation and stabilisation of many dunes by binding sand grains together. The sand couch-grass Elytrigia juncea also performs this function on the seaward edge of the dunes, and is responsible, with some other pioneers like the sea rocket Cakile maritima , for initiating the process of dune building by trapping wind blown sand.
In accreting situations small mounds of vegetation or tide-washed debris form and tend to enlarge as the wind-speed drops in the lee of the mound, allowing blowing sand (picked up from the off-shore banks) to fall out of the air stream. The pioneering plants are physiologically adapted to withstand the problems of high salt contents in the air and soil, and are good examples of stress tolerators, as well as having some ruderal characteristics.
On the inland side of dunes conditions are less severe, and links type grasslands develop with a range of grassland herbs which benefit from the reasonable nutrient status and moderately high pH of the more stable soils, especially when enough humus has accumulated in stabilised soils for water retention to be improved. Species like red fescue and lady's bedstraw are adapted to compete with each other - for nutrients, growing space and light, and are known as CSR plants - i.e. having features of Competitors, Stress tolerators and Ruderals in more or less equal proportions.
There may also be areas in old blow-outs where groundwater is near the surface, and often rises to cause flooding in the winter. Frequent, but intermittent waterlogging of the roots requires adaptations to stress, so the proportions of stress tolerators are increased here.
In nutrient-rich water, however there are some plants with very competitive strategies, like the reed ( Phragmites australis ). This is an example of a plant which makes rapid growth and suppresses other species by monopolising root and shoot space and shading out the opposition. Even its own seedlings are prevented from establishing within the existing population, but seeds are blown for long distances in copious quantities to start new colonies, whilst mature populations extend by rapid vegetative growth of lateral underground shoots - rhizomes. | https://en.wikipedia.org/wiki/Sand_dune_ecology |
A sand fence or sandbreak , similar to a snow fence , is a barrier used to force windblown, drifting sand to accumulate in a desired place. Sand fences are employed to control erosion, help sand dune stabilization , keep sand off roadways, and to recruit new material in desert areas. Sand fences are also commonly employed following storm events in order to aid in the dune recovery process, [ 1 ] particularly in developed areas where dunes are critical for protection of property. [ 2 ]
A typical construction is to attach a perforated plastic sheet to stakes at regular intervals, similar to construction site fencing or temporary sports field fencing. Another is a cedar or other lightweight wood strip and wire fence, also attached to metal stakes. A permanent sand fence is generally of larger wooden poles set deeply into the ground with large wooden planks running horizontally across them.
The drifting and settling of sand behind and in front of such a fence occurs because the wind speed on both the downwind and windward sides is less than that on the far windward side, allowing light materials such as sand to settle. [ 3 ] This creates a pile both in front of and behind the sand fence causing more sand to drop out. Conveniently the sand does not drop on the barrier itself, otherwise it would soon be buried and rendered useless. [ 4 ] | https://en.wikipedia.org/wiki/Sand_fence |
A sand rammer is a piece of equipment used in foundry sand testing to make test specimen of molding sand by compacting bulk material by free fixed height drop of fixed weight for 3 times. It is also used to determine compactibility of sands by using special specimen tubes and a linear scale.
Sand rammer consists of calibrated sliding weight actuated by cam, a shallow cup to accommodate specimen tube below ram head, a specimen stripper to strip compacted specimen out of specimen tube, a specimen tube to prepare the standard specimen of 50 mm diameter by 50 mm height [ 1 ] or 2 inch diameter by 2 inch height for an AFS standard specimen. [ 2 ]
The cam is actuated by a user by rotating the handle, causing a cam to lift the weight and let it fall freely on the frame attached to the ram head. This produces a standard compacting action to a pre-measured amount of sand. Demonstration of this apparatus can be seen here: "Sand Rammer Demonstration" on YouTube
Variety of standard specimen for Green Sand and Silicate based (CO 2 )sand are prepared using a sand rammer along with accessories
The object for producing the standard cylindrical specimen is to have the specimen become 2 inches high (plus or minus 1/32 inch) with three rams of the machine. After the specimen has been prepared inside the specimen tube, the specimen can be used for various standard sand tests such as the permeability test, the green sand compression test, the shear test, or other standard foundry tests.
The sand rammer machine can be used to measure compactability of prepared sand by filling the specimen tube with prepared sand so that it is level with the top of the tube. The tube is then placed under the ram head in the shallow cup and rammed three times. Compactability in percentage is then calculated from the resultant height of the sand inside the specimen tube.
A rammer is mounted on a base block on a solid foundation, which provides vibration damping to ensure consistent ramming.
Prerequisite equipments for sand rammer may vary from case to case basis or testing scenario: Case 1 : If the prepared sand is ready
Case 2: Experiment by preparing new sand sample
If sand needs to be prepared before making specimen following equipments may be needed
Case 3: For low compressive strength sands and mixtures: | https://en.wikipedia.org/wiki/Sand_rammer |
A sand table uses constrained sand for modelling or educational purposes. The original version of a sand table may be the abax used by early Greek students. In the modern era, one common use for a sand table is to make terrain models for military planning and wargaming .
An abax was a table covered with sand commonly used by students, particularly in Greece, to perform studies such as writing, geometry, and calculations. [ 2 ]
The abax was the predecessor to the abacus . Objects, such as stones, were added for counting and then columns for place-valued arithmetic. The demarcation between an abax and an abacus seems to be poorly defined in history; [ 3 ] moreover, modern definitions of the word abacus universally describe it as a frame with rods and beads [ 4 ] and, in general, do not include the definition of "sand table".
The sand table may well have been the predecessor to some board games . ("The word abax, or abacus, is used both for the reckoning-board with its counters and the play-board with its pieces, ..."). [ 5 ] Abax is from the old Greek for "sand table". [ 6 ]
An Arabic word for sand (or dust) is ghubar (or gubar ), and Western numerals (the decimal digits 0–9) are derived from the style of digits written on ghubar tables in North-West Africa and Iberia, also described as the 'West Arabic' or 'gubar' style. [ 7 ]
Sand tables have been used for military planning and wargaming for many years as a field expedient, small-scale map , and in training for military actions . In 1890 a Sand table room was built at the Royal Military College of Canada for use in teaching cadets military tactics; this replaced the old sand table room in a pre-college building, in which the weight of the sand had damaged the floor. [ 8 ] The use of sand tables increasingly fell out of favour with improved maps, aerial and satellite photography, and later, with digital terrain simulations. More modern sand tables have incorporated Augmented Reality , such as the Augmented Reality Sandtable (ARES) developed by the Army Research Laboratory . [ 9 ] Today, virtual and conventional sand tables are used in operations training.
In 1991, "Special Forces teams discovered an elaborate sand-table model of the Iraqi military plan for the defense of Kuwait City. Four huge red arrows from the sea pointed at the coastline of Kuwait City and the huge defensive effort positioned there. Small fences of concertina wire marked the shoreline and models of artillery pieces lined the shore area. Throughout the city were plastic models of other artillery and air defense positions, while thin, red-painted strips of board designated supply routes and main highways." [ 10 ]
In 2006, Google Earth users looking at satellite photography of China found a several kilometre large "sand table" scale model, strikingly reminiscent of a mountainous region ( Aksai Chin ) which China occupies militarily in a disputed zone with India, 2400 km from the model's location. Speculation has been rife that the terrain is used for military exercises of familiarisation. [ 11 ] [ 12 ]
A sand table is a device useful for teaching in the early grades and for special needs children . [ 13 ] [ 14 ] | https://en.wikipedia.org/wiki/Sand_table |
The Sandberg Institute ( Dutch : Sandberg Instituut ) is a postgraduate institution in Amsterdam that offers the master's programme of the Gerrit Rietveld Academy . [ 1 ] It is named after Willem Sandberg . Since 1995, the Sandberg Institute has been offering a number of master's programmes in art and design. The director of the Sandberg Institute since 2010 is Jurgen Bey. [ 2 ]
The Sandberg Institute was first founded in 1990 by Simon den Hartog, a former direct of Gerrit Rietveld Academy , originally to organise post-academic activities that included seminars and exhibitions. It is named after Willem Sandberg, the former director of the Stedelijk Museum Amsterdam , designer and advocate of the new and others in art. In 1995, it developed into the postgraduate department of the Gerrit Rietveld Academy. Under its director Jos Houweling, it offered four MA programmes in art and design: Fine Arts, Applied Arts, Design, and Interior Architecture. [ 3 ]
Jos Houweling retired in 2010, and he was succeeded by Jurgen Bey. [ 4 ] Bey introduced a series of two-year Temporary Programmes starting in 2011, such as Vacant NL, School of Missing Studies, Material Utopias, Materialism in Art, Master of Voice, and others. [ 5 ] In 2017, Sandberg also introduced Hosted Programmes in collaboration with other institutions and companies, starting with the Master Design of Experiences introduced with the University of the Underground. [ 6 ] [ 7 ]
Sandberg is housed in the building designed by Benthem & Crouwel in 2003, and it also occupies part of a new building by FedLev and Hootsmans Architects built in 2019. [ 8 ] Sandberg now has five main departments: Critical Studies, Design, The Dirty Art Department (Applied Arts), Fine Arts, and Studio for Immediate Spaces (Interior Architecture). [ 6 ]
The design department is based on engagement and experiment. From 2002 to 2008, the department was led by designer/artist Mieke Gerritzen , and from 2008 to 2019 by designer and initiator Annelys de Vet . [ 9 ] [ needs update ]
From 2005 to 2013, the Media Fonds and the Sandberg Institute co-organised the masterclass Mediafonds@Sandberg (formerly Stifo@Sandberg). Experienced media makers and designers looked together for new forms of storytelling and work on a self-formulated research question that resulted in a demo for a cultural media production. Each year, a main theme was chosen which, according to the organizers, had social urgency. The aim was to develop other, new or experimental forms of media by bringing together people and organisations from different media fields and by creating overarching insights and synergy. The master class was for the participants a broadening of the field and a deepening on thematic parts. The master class took the form of a laboratory: thematically defined with coherence between the projects and additional lectures. It was organized from the Sandberg Institute, in collaboration with the Media Fund and an annually changing third party. [ citation needed ]
The building in which the Sandberg Institute has been housed since 2005 received widespread attention after it was used temporarily in the Artvertising project of Teun Castelein, then a student in the design department. [ 10 ] Artvertising was a spatial interpretation of The Million Dollar Homepage, a 2005 internet project by Alex Tew. [ 11 ] [ 12 ] For this project, Castelein sold the facade of the building in Amsterdam as an advertising space at €19.99 a tile, and over 300 companies, institutions and individuals bought 13,000 of its tiles. It was official opened on 13 December 2006. [ 13 ] [ 14 ] [ 15 ]
The Autonomous Art department was one of the master's programs in liberal arts in the Netherlands. In the past, the department organized De Kunstvlaai , which is an alternative Dutch art's fair every two years for artists initiatives and other master courses in the arts. [ citation needed ] [ needs update ]
The Free Design department focused on spatial design. Marjan Unger was head of the department from 1995 to 2006. [ citation needed ] [ needs update ] | https://en.wikipedia.org/wiki/Sandberg_Institute |
Sandes is an Indian state-owned freeware instant messaging platform developed by the Government of India . It runs on Android , iOS and in web browsers . [ 1 ] The platform is hosted exclusively at Government infrastructure and both are governed by the rules and regulations of Government of India. [ 2 ] [ 3 ]
Sandes offers instant messaging, VoIP , File sharing and integration within various Indian Government digital services. In initial releases it was only accessible by government officials but now it is available for the public. At present, full features of the platform are only available to verified users. [ 4 ]
In 2019, the Government of India started a project to build an instant messaging platform named Government Instant Messaging System (GIMS) as part of its Make in India initiative. The main goal of the project was to provide a secure messaging platform to government employees for internal communication which doesn't arouse the security concerns attached with the communication platforms hosted abroad or those owned by foreign entities. The initial software testing started in mid-September 2019 and ran for an extensive period of time. Around 6,600 government officials from various departments participated in this pilot program which reported to have exchanged about 20 lakh messages. Later in February 2021 the client application was rebranded as Sandes and published in the official website. This time the program was made available to the public in limited number. [ 5 ] [ 6 ] [ 7 ]
The Delhi police used the Sandes app to discuss sensitive information about dignitaries during the G20 summit. [ 8 ] India's paramilitary forces transitioned to the 'Sandes App' for official communication and document sharing in January 2024, replacing WhatsApp. [ 9 ]
In July 2024, the Maharashtra government mandated the use of the Sandes app for all official communications to enhance operational security and detect potential misuse. [ 10 ]
Sandes allows users to make end-to-end encrypted one-to-one and group messages. Also allows users to make end-to-end encrypted one-to-one voice and video calls. Messaging features include forward, forward to mail, broadcast, backup, text customization and tag. Tag is a functionality to mark a message as Confidential, on Priority or as Auto Delete. If a message is marked Auto Delete, then it will be automatically deleted once the recipient reads it. Currently Sandes is integrated with NIC email, DigiLocker and eOffice. So users can access these services without leaving the platform. [ 11 ] [ 12 ]
A valid mobile number is required to sign up. Public users are limited to one-to-one chat. An official group is limited to 200 members. A casual group is limited to 50 members. Broadcast list is limited to ten contacts at a time. Users are only allowed to send the following file types: documents (doc, docx, xls, xlsx, ppt, pptx, pdf), images (jpeg, jpg, png), audio (mp3, m4a), video (mp4). File size is limited to 15mb per file. [ 13 ] | https://en.wikipedia.org/wiki/Sandes_(software) |
Sandi Klavžar (born 5 February 1962) is a Slovenian mathematician working in the area of graph theory and its applications. He is a professor of mathematics at the University of Ljubljana .
Klavžar received his Ph.D. from the University of Ljubljana in 1990, under the supervision of Wilfried Imrich and Tomaž Pisanski . [ 1 ]
Klavžar's research concerns graph products, metric graph theory, chemical graph theory, graph domination, and the Tower of Hanoi. Together with Wilfried Imrich and Richard Hammack, he is the author of the book Handbook of Product Graphs (CRC Press, 2011). Together with Andreas M. Hinz, Uroš Milutinović, and Ciril Petr, he is the author of the book The Tower of Hanoi – Myths and Maths (Springer, Basel, 2013).
In 2007, Klavžar received the Zois award for exceptional contributions to science and mathematics. | https://en.wikipedia.org/wiki/Sandi_Klavžar |
The Sandia method (also known as Veers method) is a method for generating a turbulent wind profile that can be used in aero-elastic software to evaluate the fatigue imparted on a turbine in a turbulent environment. That is, it generates time series of wind speeds at a set of points on a surface, say the plane of the rotor of a wind turbine. Analysis is performed initially in the frequency domain, where turbulence can be described quantitatively with more ease than the time domain. Then, the time series are obtained by inverse fast Fourier transforms.
In its original form, the Sandia method only simulates the u-component of the wind; that is, the wind was modelled as propagating in a direction perpendicular to the plane of the rotor. Work carried out by NREL, specifically Kelley, suggested that a considerable amount of turbulent energy existed in the v-component (the v-component is parallel to both the plane of the rotor and the Earth). As such, the Sandia method was upgraded such that it included the v-component and w-component. Further upgrades have been performed such that the wind profile exhibits cross-axis correlation (turbulent fluctuations in one component being somehow connected to turbulent fluctuations in another). However, these are not considered in this article.
Although turbulence leads to unpredictable results in the time domain, it can, to some extent, be characterized in the frequency domain. Turbulent fluctuations are dominated by low frequency components, with higher frequency components having less influence. For further information, see Kolmogorov's theory on turbulence .
Several models of frequency domain representations of point wind speeds have been developed: the von Kármán wind turbulence model and Dryden Wind Turbulence Model are examples of such.
A spectrum in its original form is a continuous function. However, computer programmes operate on discrete functions. Thus a modification to whatever type of spectrum, be it Kaimal, von Karman, or some other spectrum, is needed. This is given below:
where S ( ω k ) {\displaystyle S(\omega _{k})} is the discretized spectrum evaluated only at the discrete frequencies ω k {\displaystyle \omega _{k}} , S ( ω = ω k ) {\displaystyle S(\omega =\omega _{k})} is the continuous spectrum evaluated at ω = ω k {\displaystyle \omega =\omega _{k}} and Δ ω {\displaystyle \Delta \omega } is the size of the step between consecutive frequencies being considered.
When generating a time series of wind speeds for a set of points across a surface, coherence needs to be taken into account. That is, the instantaneous wind speed at some point, A, will bear some resemblance to the wind speed at some other point, B. Clearly, the resemblance is influenced by the separation of points A and B. That is, two points separated by a large distance will show less similarity to each other than two neighbouring points on the surface.
In addition, one would expect low frequency components of the wind speeds at points A and B to show more correlation than high frequency components. As such, many coherence functions have been proposed: Davenport, Solari, etc. The Solari coherence spectrum is provided as an example:
where C {\displaystyle C} is a constant, Δ r i j {\displaystyle \Delta r_{ij}} is the separation of points i {\displaystyle i} and j {\displaystyle j} on the surface, ω k {\displaystyle \omega _{k}} is the frequency, and u i {\displaystyle u_{i}} and u j {\displaystyle u_{j}} are the mean wind speeds at points i {\displaystyle i} and j {\displaystyle j} respectively. The indices i {\displaystyle i} and j {\displaystyle j} run from 1 to n, and the index k {\displaystyle k} covers the frequency range. From the coherence function stems the coherence matrix. To cover all relationships between all points, the coherence function must be an n 2 {\displaystyle n^{2}} -by- n 2 {\displaystyle n^{2}} -by- ω {\displaystyle \omega } matrix. Clearly, the coherence matrix is symmetric about the main diagonal if we are restricting ourselves to looking at the coherence function at a single frequency. This is because the spatial separation between points A and B is the same as the spatial separation between B and A. That is, for a n-by-n grid, only ( n 4 + n 2 ) / 2 {\displaystyle (n^{4}+n^{2})/2} elements need to be calculated for each frequency.
It is worth noting at this point that whilst the coherence matrix is strictly a 3-dimensional matrix (i, j, and k), computer programmes which implement the Sandia method typically reduce the coherence matrix to a 2-dimensional matrix where the frequency dimension has been 'removed'. This is to ease computational requirements. A 2-dimensional matrix is also required to perform some of the actions on the spectral matrix, such as a Cholesky decomposition, which is mentioned later. Of course, variation in frequency is still applied. However, the following process is carried out in full for one given frequency before proceeding to the next frequency. As such, in the following section, a power spectrum refers to the value of the power spectrum at a given frequency and not the full set of values across the frequency range being used. That is,
and
S i j k → S i j ( ω k ) {\displaystyle S_{ijk}\rightarrow S_{ij}(\omega _{k})}
where an element of S, S i j k {\displaystyle S_{ijk}} , would have given the strength of the spectrum at a particular frequency ω k {\displaystyle \omega _{k}} at a particular point in space.
Power spectra are needed for each of the n 2 {\displaystyle n^{2}} points on the surface; this encapsulates information about the turbulence intensity for each point. Under IEC standards, only one power spectrum is used; that is, all n 2 {\displaystyle n^{2}} points have the same turbulence intensity.
With the power spectra, the spectral matrix can be formed. This a n 2 {\displaystyle n^{2}} -by- n 2 {\displaystyle n^{2}} matrix. The main diagonal of the spectral matrix contains the previously defined spectra for all n 2 {\displaystyle n^{2}} points on the surface. The off-main diagonal elements contain all the cross spectra between the points. The cross spectra are determined by the following function:
Due to the symmetry of the coherence matrix, only ( n 4 + n 2 ) / 2 {\displaystyle (n^{4}+n^{2})/2} elements are independent. This property can be exploited to lighten memory requirements when writing a programme to simulate the Sandia method.
The spectral matrix, S ( ω k ) {\displaystyle S(\omega _{k})} , can be written as the matrix product of a matrix, H ( ω k ) {\displaystyle H(\omega _{k})} , and its transpose. That is,
H ( ω k ) {\displaystyle H(\omega _{k})} is ultimately needed to obtain the complex Fourier co-efficients of the Fourier transforms of the time series of the wind speeds at all the points on the surface. Note - if the Fourier transform of a time domain function, x ( t ) {\displaystyle x(t)} , is X ( ω ) {\displaystyle X(\omega )} , then the resultant spectrum is S ( ω ) ∝ X ( ω ) X ∗ ( ω ) {\displaystyle S(\omega )\propto X(\omega )X^{*}(\omega )} ; for multiple time domain functions, the Fourier co-efficients can be stored in a matrix, which then means that the above equation is applicable.
Obviously, there are an infinite number of solutions to the above expression; consequently, the assumption that H ( ω k ) {\displaystyle H(\omega _{k})} is a lower triangular matrix is made such that only one solution exists. The solution can be found via a Cholesky decomposition. The resultant H ( ω k ) {\displaystyle H(\omega _{k})} matrix can be thought of as the weighting factors for the
linear combination of N independent, unit-magnitude, white-noise inputs that will
yield N correlated outputs with the correct spectral matrix. [ 1 ]
To get the complex Fourier co-efficients associated with the Fourier transform of the time series of the wind speeds, a column vector, V {\displaystyle V} is obtained by multiply the H ( ω k ) {\displaystyle H(\omega _{k})} matrix by a column vector containing n 2 {\displaystyle n^{2}} values of Gaussian white noise, X ( ω k ) {\displaystyle X(\omega _{k})} , as shown below:
The column vector gives the Fourier co-efficients for all points on the grid at a given frequency. This is then built up into a two dimensional matrix which covers the complex Fourier co-efficients for all points across all frequencies. Then, an inverse fast Fourier transform is performed to get the time series. That is, | https://en.wikipedia.org/wiki/Sandia_method |
The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts using copper salts as reagents or catalysts. [ 1 ] [ 2 ] [ 3 ] [ 4 ] It is an example of a radical-nucleophilic aromatic substitution . The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation , cyanation , trifluoromethylation , and hydroxylation .
The reaction was discovered in 1884 by Swiss chemist Traugott Sandmeyer , when he attempted to synthesize phenylacetylene from benzenediazonium chloride and copper(I) acetylide . Instead, the main product he isolated was chlorobenzene . [ 5 ] In modern times, the Sandmeyer reaction refers to any method for substitution of an aromatic amino group via preparation of its diazonium salt followed by its displacement with a nucleophile in the presence of catalytic copper(I) salts.
The most commonly employed Sandmeyer reactions are the chlorination, bromination, cyanation, and hydroxylation reactions using CuCl , CuBr , CuCN , and Cu 2 O , respectively. More recently, trifluoromethylation of diazonium salts has been developed and is referred to as a 'Sandmeyer-type' reaction. Diazonium salts also react with boronates, iodide, thiols , water, hypophosphorous acid and others, [ 6 ] and fluorination can be carried out using tetrafluoroborate anions ( Balz–Schiemann reaction ). However, since these processes do not require a metal catalyst, they are not usually referred to as Sandmeyer reactions. In numerous variants that have been developed, other transition metal salts, including copper(II), iron(III) and cobalt(III) have also been employed. [ 7 ] Due to its wide synthetic applicability, the Sandmeyer reaction, along with other transformations of diazonium compounds, is complementary to electrophilic aromatic substitution .
The Sandmeyer reaction is an example of a radical-nucleophilic aromatic substitution (S RN Ar). The radical mechanism of the Sandmeyer reaction is supported by the detection of biaryl byproducts. [ 8 ] The substitution of the aromatic diazo group with a halogen or pseudohalogen is initiated by a one-electron transfer mechanism catalyzed by copper(I) to form an aryl radical with loss of nitrogen gas. [ 9 ] [ 10 ] [ 11 ] [ 8 ] The substituted arene is possibly formed by direct transfer of Cl, Br, CN, or OH from a copper(II) species to the aryl radical to produce the substituted arene and regenerate the copper(I) catalyst. In an alternative proposal, a transient copper(III) intermediate, formed from coupling of the aryl radical with the copper(II) species, undergoes rapid reductive elimination to afford the product and regenerate copper(I). [ 12 ] [ 13 ] [ 14 ] However, evidence for such an organocopper intermediate is weak and mostly circumstantial, [ 15 ] [ 16 ] and the exact pathway may depend on the substrate and reaction conditions.
Variations on the Sandmeyer reaction have been developed to fit multiple synthetic applications. These reactions typically proceed through the formation of an aryl diazonium salt followed by a reaction with a copper(I) salt to yield a substituted arene:
There are many synthetic applications of the Sandmeyer reaction.
One of the most important uses of the Sandmeyer reaction is the formation of aryl halides. The solvent of choice for the synthesis of iodoarenes is diiodomethane , [ 17 ] [ 18 ] while for the synthesis of bromoarenes , bromoform is used. For the synthesis of chloroarenes , chloroform is the solvent of choice. [ 19 ] The synthesis of (+)- curcuphenol , a bioactive compound that displays antifungal and anticancer activity, employs the Sandmeyer reaction to substitute an amine group by a bromo group. [ 20 ]
One bromination protocol employs a Cu(I)/Cu(II) mixture with additional amounts of the bidentate ligand phenanthroline and phase-transfer catalyst dibenzo-18-crown-6 to convert an aryl diazonium tetrafluoroborate salt to an aryl bromide. [ 21 ]
The Balz–Schiemann reaction uses tetrafluoroborate and delivers the halide-substituted product, fluorobenzene , which is not obtained by the use of copper fluorides . This reaction displays motifs characteristic of the Sandmeyer reaction. [ 22 ]
Another use of the Sandmeyer reaction is for cyanation which allows for the formation of benzonitriles , an important class of organic compounds. A key intermediate in the synthesis of the antipsychotic drug Fluanxol is synthesized by a cyanation through the Sandmeyer reaction. [ 23 ]
The Sandmeyer reaction has also been employed in the synthesis of neoamphimedine, a compound that is suggested to target topoisomerase II as an anti-cancer drug. [ 24 ]
It has been demonstrated that Sandmeyer-type reactions can be used to generate aryl compounds functionalized by trifluoromethyl substituent groups. This process of trifluoromethylation provides unique chemical properties with a wide variety of practical applications. Particularly, pharmaceuticals with CF 3 groups have enhanced metabolic stability , lipophilicity , and bioavailability . Sandmeyer-type trifluoromethylation reactions feature mild reaction conditions and greater functional group tolerance relative to earlier methods of trifluoromethylation. [ 25 ] [ 26 ] An example of a Sandmeyer-type trifluoromethylation reaction is presented below. [ 27 ]
The Sandmeyer reaction can also be used to convert aryl amines to phenols proceeding through the formation of an aryl diazonium salt. In the presence of copper catalyst, such as copper(I) oxide , and an excess of copper(II) nitrate , this reaction takes place readily at room temperature neutral water. [ 28 ] This is in contrast to the classical procedure (known by the German name Verkochung [ de ] ), which calls for boiling the diazonium salt in aqueous acid, a process that is believed to involve the aryl cation instead of radical and is known to generate other nucleophilic addition side products in addition to the desired hydroxylation product. | https://en.wikipedia.org/wiki/Sandmeyer_reaction |
Sandoz Group AG is a Swiss company that focuses on generic pharmaceuticals and biosimilars. [ 4 ] Prior to October 2023, it was part of a division of Novartis that was established in 2003, when Novartis united all of its generics businesses under the name Sandoz. Before this, the company existed as an independent pharmaceutical manufacturer until 1996, when it was merged with Ciba-Geigy to form Novartis. Prior to the merger, it specialized in medicines used in organ transplants, such as Sandimmune , and various antipsychotics and migraine medicines. Its headquarters were in Holzkirchen , Germany and after the spin-off from Novartis, the headquarters moved to Basel, Switzerland, with most of global functions operating from Holzkichen in Germany, Prague in Czechia, [ 5 ] and Barcelona in Spain. Sandoz is the global leader in generic pharmaceuticals and biosimilars. [ 6 ] [ 7 ] [ 8 ]
The company was founded in 1886 by Alfred Kern (1850–1893) and Edouard Sandoz (1853–1928) in Basel (Switzerland) under the name Chemiefirma Kern und Sandoz . Initially the company focused on production of dyes namely alizarin blue and auramine . When Kern died, the company changed its name to Chemische Fabrik vormals Sandoz in 1895 and began producing pharmaceuticals for the first time the same year. As early as 1895, the first pharmaceutical substance called antipyrine was produced to reduce fever. In 1899 they started producing saccharin . [ 9 ]
In 1917, Sandoz entered pharmaceutical research when Arthur Stoll (1887–1971) was hired, and, in 1929, Calcium Sandoz was introduced, laying the foundation research into modern calcium therapy. [ 10 ] [ 11 ]
In 1918, Arthur Stoll isolated ergotamine from ergot ; the substance was eventually used to treat migraine and headaches and was introduced under the trade name Gynergen in 1921. [ 12 ]
In 1938 Albert Hofmann produced the synthetic substance lysergic acid diethylamide , better known as LSD. The psychoactive properties of this preparation were nevertheless not discovered until 1943, when Hofmann ingested a small amount by accident. [ 13 ] [ 14 ] From 1947 to the mid-60s, LSD was sold by Sandoz under the name Delysid . [ 15 ] It was marketed as a treatment for a wide variety of mental ailments , ranging from alcoholism to sexual deviancy . Sandoz suggested in its marketing literature that psychiatrists take LSD themselves, [ 16 ] to gain a better subjective understanding of the schizophrenic experience, and many did exactly that and so did other scientific researchers. The Sandoz product received mass publicity as early as 1954, in a Time magazine feature. [ 17 ] Research on LSD peaked in the 1950s and early 1960s. The CIA purchased quantities of LSD from Sandoz for use in its illegal human experimentation program known as MKUltra . [ 18 ] Sandoz withdrew the drug from the market in 1965. The drug became a cultural novelty of the 1960s after psychologist Timothy Leary at Harvard University began to promote its use for recreational and spiritual experiences among the general public. [ 19 ]
In 1939, Kern & Sandoz became Sandoz Ltd., a name it operated under for nearly sixty years. [ 20 ]
In 1963, Sandoz acquired Biochemie GmbH, which was producing and supplying scarce, urgently needed acid-resistant penicillin. [ 21 ]
In 1967, Sandoz merged with Wander AG and diversified into the dietetics business with Ovomaltine and Isostar . [ 22 ]
In 1972, Sandoz acquired Delmark, Wasabröd, Wasa, the Swedish crisp bread producer Wasa in 1982. [ 23 ]
In 1986, Velsicol Chemical Corporation acquired the agrochemicals division of Sandoz. [ 24 ]
In 1994, Sandoz bought Gerber Products Company, expanding its research into biopharmacueticals. [ 25 ] [ 26 ]
In 1995, the specialty chemicals division became an independent company under the name Clariant , based in Muttenz . [ 27 ] [ 28 ] [ 29 ]
On December 20, 1996, the merger of Sandoz and Ciba-Geigy led to the creation of Novartis. The Sandoz brand name was then only used in the pharmaceutical business for over-the-counter medicines. [ 30 ] [ 7 ]
The former company name Sandoz was reactivated in May 2003 with the merger of the globally differently named generics companies of the parent company Novartis under the uniform brand name Sandoz. [ 21 ] In addition to the name, the company logo used before the merger was also adopted. [ 21 ]
In 2002, Sandoz acquired Lek Pharmaceuticals d.d., Slovenia's largest pharmaceutical company. [ 31 ]
In 2003, Novartis united its global generics businesses under a single global brand, reestablishing the name Sandoz as a division of Novartis. [ 21 ] The Amifarma S.L. production plant in Palafolls, located near Barcelona, Spain was also acquired. [ 21 ]
In February 2005, Sandoz acquired over Hexal AG and Eon Labs. The integration into Sandoz created the second largest generics group in the world and the largest on the German market with annual sales of 7.6 billion US dollars (2008) and over 23,000 employees in 130 countries. The headquarters have been in Holzkirchen since 2005. Sandoz's Swiss administrative headquarters are in Rotkreuz ZG in the municipality of Risch in the canton of Zug. [ 32 ]
In 2006, Omnitrope , a recombinant human growth hormone, was approved by the European Medicines Agency (EMA) and also became the first biosimilar to receive approval from the FDA. [ 33 ]
In 2007, the first complex biosimilar, Binocrit was approved in the EU. [ 34 ]
In 2009, Sandoz acquired EBEWE Pharma's specialty generic injectables division and in 2010, acquired Oriel Therapeutics. [ 35 ] [ 36 ]
In 2012, Sandoz acquired Fougera Pharmaceuticals, entering the generic (topical) dermatology business. [ 37 ]
In November 2018, it was announced that Novartis would convert Sandoz into an independent entity over the next two years. [ 38 ] In March 2019, it was announced that CEO Richard Francis had resigned for personal reasons and that Francesco Balestrieri, Sandoz's European head, had taken over management ad interim. [ 39 ] [ 40 ] Richard Saynor was appointed as CEO later in 2019. [ 40 ]
In August 2022, Novartis said the spin-off of Sandoz into a standalone company would be completed by the end of 2023. [ 41 ] As part of the spin-off, Sandoz announced in June 2023 it would move its headquarters from Holzkirchen , Germany to Basel, Switzerland. [ 42 ]
In July 2023, Sandoz launched a biosimilar version of AbbVie Inc 's Humira , under the label, Hyrimoz . [ 43 ]
In September 2023, Novartis announced that the spin-off had been approved by its shareholders and that it would be completed by the next month, resulting in Novartis shareholders receiving one Sandoz share for every five Novartis shares. [ 44 ] [ 45 ] Sandoz was listed on the SIX Swiss Exchange with a market capitalization between $18 billion and $25bn. [ 46 ] [ 45 ]
On October 4, 2023, Novartis completed the spin-off of Sandoz as a stand-alone company. [ 47 ]
The B2B business unit of Sandoz, dedicated to supplying active pharmaceutical ingredients (APIs) , out-licensing of Finished Dosage Forms (FDFs) , and Contract Manufacturing Organization (CMO) services, continues to operate from its global headquarters in Kufstein , Austria, which was inaugurated in June 2023. The unit supplies over 200 customers in 77 countries and delivers around 800 million treatments per year. [ 48 ]
In January 2024, Sandoz announced it would acquire biosimilar drug for vision Cimerli For $170 million from Coherus BioSciences. [ 49 ] The acquisition was completed in March 2024. [ 50 ]
In February 2024, Sandoz US and its subsidiary Fougera Pharmaceuticals Inc. - indirect subsidiaries of Sandoz Group AG reached a USD 265 million settlement agreement in the US related to a generics direct purchaser class action lawsuit. [ 51 ]
In April 2024, Sandoz reached an agreement with Amgen to resolve all patent disputes between the two companies relating to the US Food and Drug Administration (FDA)-approved Sandoz denosumab biosimilars. [ 52 ]
In November 2024, Sandoz inaugurated the new headquarters in Basel, Switzerland. [ 53 ] [ 54 ]
On November 1, 1986, a major fire broke out in a warehouse containing 1,350 tonnes (2,980,000 lb) of chemicals in what was then Sandoz in Schweizerhalle . The thick smoke, the stench and the unknown composition of the combustion gases caused the authorities in the neighboring communities to alert the population early in the morning with a general siren alarm and a curfew of several hours was imposed. No people suffered acute harm, with the exception of three people with pre-existing asthma who required hospitalization. However, the toxins found their way into the Rhine via the extinguishing water, where they caused a large number of fish to die off. [ 55 ]
On November 11, 1986, the analysis of water samples proved that at the same time as the Rhine was being polluted by the contaminated extinguishing water from the Sandoz area, 400 kg of atrazine , a herbicide, had been discharged into the Rhine from the neighboring chemical company Ciba-Geigy. [ 56 ] [ 57 ]
The official investigation report came to the conclusion (only " on the basis of theoretical considerations ") that when pallets were packed with Prussian blue, incorrect handling of a hot air blower led to a hot spot, which could be the cause. Subsequent trials, however, resulted in no conviction. The plant now belongs to Clariant . [ 58 ]
To this day, the landfill left after the fire continues to pollute the groundwater in Muttenz and is actively monitored by Novartis, as the legal successor to Sandoz, and the environmental authorities of the Canton of Basel-Landschaft. [ 59 ] [ 60 ]
To commemorate the spill, there is a plastic market table by Bettina Eichin in the cloister of Basel Munster . [ 61 ] | https://en.wikipedia.org/wiki/Sandoz |
Sandra Pizzarello (24 April 1933 – 24 October 2021) was an Italian biochemist known for her co-discovery of amino acid enantiomeric excess in carbonaceous chondrite meteorites . Her research interests concerned the characterization of meteoritic organic compounds in elucidating the evolution of planetary homochirality . Pizzarello was a project collaborator and co-investigator for the NASA Astrobiology Institute (NAI), the president of the International Society for the Study of the Origin of Life (2014-2017), and an emerita professor at Arizona State University (ASU).
Sandra Pizzarello was born in Venice , Italy on 24 April 1933. In 1955, she graduated summa cum laude from the University of Padua earning her Doctor of Biological Sciences degree under her adviser Professor Roncato. Pizzarello went on to work as a research associate developing tranquilizers for Farmitalia Research Laboratories in the Department of Neuropharmacology. Over the course of several years, Pizzarello transitioned from research to raising a family. Following a career opportunity for her husband, an aeronautical engineer and computer scientist, she moved her family to Phoenix, Arizona in 1970.
Once Pizzarello's youngest of four children finished primary school, her focus returned to her career after a decade away from scientific research . She audited a graduate biochemistry seminar course at ASU where she met Professor John Read Cronin , future co-discoverer of amino acid enantiomeric excess in meteorites . Due to her outstanding performance in the course, she was offered a job to work with Cronin at the university as a research professor in analyzing the recently recovered Murchison meteorite .
Sandra Pizzarello died on 24 October 2021, at the age of 88. [ 1 ] [ 2 ]
Sandra Pizzarello's research over the last forty years involved the analysis of organic compounds in several carbonaceous chondrites , particularly molecular , chiral , and isotopic characterization of amino acids . Because the formation of these organic-rich meteorites pre-date the origin of life , they had been under investigation as potential sites of primal organic compounds which could shed light on abiogenesis , specifically the origin of biological homochirality . [ 3 ] Such studies, however, had been inconclusive until 1997 when Cronin and Pizzarello detected 7-9% L- enantiomeric excesses of three abiological amino acids while analyzing the Murchison meteorite . [ 3 ]
Given Earth's history of meteoric impacts and the observation that meteors contain an excess of the biologically relevant L- stereoisomer of certain amino acids , Pizzarello studied the effect of meteoritic amino acids in enantiomeric excess on the formation of other biological molecules . [ 4 ] In one study, Pizzarello found that nonracemic solutions of abiological isovaline and proteinogenic alanine can direct the condensation of glycolaldehyde to produce nonracemic solutions of threose and erythrose via an aldol reaction concluding that amino acids can act as asymmetric catalysts in carbohydrate synthesis. [ 4 ] These findings support the origin of life hypothesis that homochirality originated prior to life and from extraterrestrial origins. [ 4 ] However, Pizzarello's theoretical inquiries into cosmochemical evolution remain debated based on suspect analytical evidence of meteoritic enantiomeric excesses . [ 5 ] [ 6 ] [ 7 ] | https://en.wikipedia.org/wiki/Sandra_Pizzarello |
A sandwich panel is any structure made of three layers: a low-density core ( PIR , mineral wool , XPS ), and a thin skin-layer bonded to each side. Sandwich panels are used in applications where a combination of high structural rigidity and low weight is required.
The structural functionality of a sandwich panel is similar to the classic I-beam , where two face sheets primarily resist the in-plane and lateral bending loads
(similar to flanges of an I- beam), while the core material mainly resists the shear loads (similar to the web of an I-beam). [ 1 ] The idea is to use a light/soft but thick layer for the core and strong but thin layers for face sheets. This results in increasing the overall thickness of the panel, which often improves the structural attributes, like bending stiffness, and maintains or even reduces the weight. [ 2 ]
Sandwich panels are an example of a sandwich-structured composite : the strength and lightness of this technology makes it popular and widespread. Its versatility means that the panels have many applications and come in many forms: the core and skin materials can vary widely and the core may be a honeycomb or a solid filling. Enclosed panels are termed cassettes .
One obvious application is in aircraft, where mechanical performance and weight-saving are essential. Transportation and automotive applications also exist. [ 3 ]
In building and construction, these prefabricated products designed for use as building envelopes. They appear in industrial and office buildings, in clean and cold rooms and also in private houses, whether renovation or new-build. They combine a high-quality product with high flexibility regarding design. They generally have a good energy-efficiency and sustainability. [ 4 ]
In packaging, applications include fluted polypropylene boards and polypropylene honeycomb boards. [ 5 ]
Due to the ability of 3D printers to fabricate complex sandwich panels there has recently been a flourishing of research in this area covering energy absorption, [ 6 ] natural fiber, [ 7 ] with continuous synthetic fibers, [ 8 ] and for vibration. [ 9 ] The promise of this technology is for new geometric complexities in sandwich panels not possible with other fabrication processes.
Structural insulated panels or structural insulating panels (commonly referred to as SIP s) are panels used as a building material .
Aluminium composite panels ( ACP ), made of aluminium composite material ( ACM ), are flat panels consisting of two thin coil-coated aluminium sheets bonded to a non-aluminium core. ACPs are frequently used for external cladding or facades of buildings, insulation, and signage . [ 10 ]
ACP is mainly used for external and internal architectural cladding or partitions, false ceilings, signage, machine coverings, container construction, etc. Applications of ACP are not limited to external building cladding, but can also be used in any form of cladding such as partitions, false ceilings, etc. ACP is also widely used within the signage industry as an alternative to heavier, more expensive substrates.
ACP has been used as a light-weight but very sturdy material in construction, particularly for transient structures like trade show booths and similar temporary elements. It has recently also been adopted as a backing material for mounting fine art photography, often with an acrylic finish using processes like Diasec or other face-mounting techniques. ACP material has been used in famous structures as Spaceship Earth , VanDusen Botanical Garden , and the Leipzig branch of the German National Library . [ 11 ]
These structures made optimal use of ACP through its cost, durability, and efficiency. Its flexibility, low weight, and easy forming and processing allow for innovative design with increased rigidity and durability.
Where the core material is flammable, the usage must be considered. The standard ACP core is polyethylene (PE) or polyurethane (PU). These materials do not have good fire-resistant (FR) properties unless specially treated and are therefore not generally suitable as a building material for dwellings; several jurisdictions have banned their use completely. [ 12 ] Arconic, owner of the Reynobond brand, cautions the prospective buyer. Concerning the core, it says that distance of the panel from the ground is a determinant of "which materials are safer to use". In a brochure it has a graphic of a building in flames, with the caption "[a]s soon as the building is higher than the firefighters’ ladders, it has to be conceived with an incombustible material". It shows that the Reynobond polyethylene product is for up to circa 10 meters; the fire-retardant product (c. 70% mineral core) from there to up to c. 30 meters, the height of the ladder; and the European A2-rated product (c. 90% mineral core) for anything above that. In this brochure, Fire Safety in High-rise Buildings: Our Fire Solutions , product specification is only given for the last two products. [ 13 ]
The cladding materials, in this case having the highly combustible Polyethylene (PE) core, were implicated as the principal cause of the rapid spread of flame in the 2017 Grenfell Tower fire in London. [ 14 ] It has also been involved in high-rise building fires in Melbourne , Australia; France; the United Arab Emirates; South Korea; and the United States. [ 15 ] Fire-rated cores (typically designated as "FR" by the manufacturers) are a safer alternative as they have a maximum of 30% Polyethylene Content, and will self-extinguish in the absence of heat/ventilation. [ 16 ] As with any building product, fitness for use is dependent on multiple other products and methods. In the case of ACP, building codes in USA have many requirements related to the wall assembly depending on the materials used and the building type. When these building codes are followed, the FR core products are safe. Note that the term ACP does not apply to sandwich panels with Mineral Wool cores, which fall under the category of Insulated Metal Panels (IMP).
The aluminium sheets can be coated with polyvinylidene fluoride (PVDF), fluoropolymer resins (FEVE), or polyester paint. Aluminium can be painted in any kind of colour, and ACPs are produced in a wide range of metallic and non-metallic colours as well as patterns that imitate other materials, such as wood or marble . The core is commonly low-density polyethylene (PE), or a mix of low-density polyethylene and mineral material to exhibit fire retardant properties. [ 10 ]
3A Composites (formerly Alcan Composites & Alusuisse) invented aluminium composites in 1964 - as a joint invention with BASF- and commercial production of Alucobond commenced in 1969. The product was patented in 1971, a patent which expired in 1991. After the expiration of the patent several companies started commercial production such as Reynobond (1991), Alpolic (Mitsubishi Chemicals, 1995), etalbond (1995). Today, it is estimated [ by whom? ] that more than 200 companies across the world are producing ACP.
Sandwich panel construction techniques have experienced considerable development in the last 40 years. Previously, sandwich panels were considered products suitable only for functional constructions and industrial buildings. However, their good insulation characteristics, their versatility, quality and appealing visual appearance, have resulted in a growing and widespread use of the panels across a huge variety of buildings.
The qualities that have produced the rapid growth in the use of sandwich panels, particularly in construction, include: | https://en.wikipedia.org/wiki/Sandwich_panel |
Sandwich theory [ 1 ] [ 2 ] describes the behaviour of a beam , plate , or shell which consists of three layers—two facesheets and one core. The most commonly used sandwich theory is linear and is an extension of first-order beam theory . The linear sandwich theory is of importance for the design and analysis of sandwich panels , which are of use in building construction, vehicle construction, airplane construction and refrigeration engineering.
Some advantages of sandwich construction are:
The behavior of a beam with sandwich cross-section under a load differs from a beam with a constant elastic cross section. If the radius of curvature during bending is large compared to the thickness of the sandwich beam and the strains in the component materials are small, the deformation of a sandwich composite beam can be separated into two parts
Sandwich beam, plate, and shell theories usually assume that the reference stress state is one of zero stress. However, during curing, differences of temperature between the facesheets persist because of the thermal separation by the core material. These temperature differences, coupled with different linear expansions of the facesheets, can lead to a bending of the sandwich beam in the direction of the warmer facesheet. If the bending is constrained during the manufacturing process, residual stresses can develop in the components of a sandwich composite. The superposition of a reference stress state on the solutions provided by sandwich theory is possible when the problem is linear. However, when large elastic deformations and rotations are expected, the initial stress state has to be incorporated directly into the sandwich theory.
In the engineering theory of sandwich beams, [ 2 ] the axial strain is assumed to vary linearly over the cross-section of the beam as in Euler-Bernoulli theory , i.e.,
Therefore, the axial stress in the sandwich beam is given by
where E ( z ) {\displaystyle E(z)} is the Young's modulus which is a function of the location along the thickness of the beam. The bending moment in the beam is then given by
The quantity D {\displaystyle D} is called the flexural stiffness of the sandwich beam. The shear force Q x {\displaystyle Q_{x}} is defined as
Using these relations, we can show that the stresses in a sandwich beam with a core of thickness 2 h {\displaystyle 2h} and modulus E c {\displaystyle E^{c}} and two facesheets each of thickness f {\displaystyle f} and modulus E f {\displaystyle E^{f}} , are given by
we can write the axial stress as
The equation of equilibrium for a two-dimensional solid is given by
where τ x z {\displaystyle \tau _{xz}} is the shear stress . Therefore,
where C ( x ) {\displaystyle C(x)} is a constant of integration.
Therefore,
Let us assume that there are no shear tractions applied to the top face of the sandwich beam. The shear stress in the top facesheet is given by
At z = h + f {\displaystyle z=h+f} , τ x z ( x , h + f ) = 0 {\displaystyle \tau _{xz}(x,h+f)=0} implies that C ( x ) = 0 {\displaystyle C(x)=0} . Then the shear stress at the top of the core, z = h {\displaystyle z=h} , is given by
Similarly, the shear stress in the core can be calculated as
The integration constant C ( x ) {\displaystyle C(x)} is determined from the continuity of shear stress at the interface of the core and the facesheet. Therefore,
and
For a sandwich beam with identical facesheets and unit width, the value of D {\displaystyle D} is
If E f ≫ E c {\displaystyle E^{f}\gg E^{c}} , then D {\displaystyle D} can be approximated as
and the stresses in the sandwich beam can be approximated as
If, in addition, f ≪ 2 h {\displaystyle f\ll 2h} , then
and the approximate stresses in the beam are
If we assume that the facesheets are thin enough that the stresses may be assumed to be constant through the thickness, we have the approximation
Hence the problem can be split into two parts, one involving only core shear and the other involving only bending stresses in the facesheets.
The main assumptions of linear sandwich theories of beams with thin facesheets are:
However, the xz shear-stresses in the core are not neglected.
The constitutive relations for two-dimensional orthotropic linear elastic materials are
The assumptions of sandwich theory lead to the simplified relations
and
The equilibrium equations in two dimensions are
The assumptions for a sandwich beam and the equilibrium equation imply that
Therefore, for homogeneous facesheets and core, the strains also have the form
Let the sandwich beam be subjected to a bending moment M {\displaystyle M} and a shear force Q {\displaystyle Q} . Let the total deflection of the beam due to these loads be w {\displaystyle w} . The adjacent figure shows that, for small displacements, the total deflection of the mid-surface of the beam can be expressed as the sum of two deflections, a pure bending deflection w b {\displaystyle w_{b}} and a pure shear deflection w s {\displaystyle w_{s}} , i.e.,
From the geometry of the deformation we observe that the engineering shear strain ( γ {\displaystyle \gamma } ) in the core is related the effective shear strain in the composite by the relation
Note the shear strain in the core is larger than the effective shear strain in the composite and that small deformations ( tan γ = γ {\displaystyle \tan \gamma =\gamma } ) are assumed in deriving the above relation. The effective shear strain in the beam is related to the shear displacement by the relation
The facesheets are assumed to deform in accordance with the assumptions of Euler-Bernoulli beam theory. The total deflection of the facesheets is assumed to be the superposition of the deflections due to bending and that due to core shear. The x {\displaystyle x} -direction displacements of the facesheets due to bending are given by
The displacement of the top facesheet due to shear in the core is
and that of the bottom facesheet is
The normal strains in the two facesheets are given by
Therefore,
The shear stress in the core is given by
or,
The normal stresses in the facesheets are given by
Hence,
The resultant normal force in a face sheet is defined as
and the resultant moments are defined as
where
Using the expressions for the normal stress in the two facesheets gives
In the core, the resultant moment is
The total bending moment in the beam is
or,
The shear force Q x {\displaystyle Q_{x}} in the core is defined as
where κ {\displaystyle \kappa } is a shear correction coefficient. The shear force in the facesheets can be computed from the bending moments using the relation
or,
For thin facesheets, the shear force in the facesheets is usually ignored. [ 2 ]
The bending stiffness of the sandwich beam is given by
From the expression for the total bending moment in the beam, we have
For small shear deformations, the above expression can be written as
Therefore, the bending stiffness of the sandwich beam (with f ≪ 2 h {\displaystyle f\ll 2h} ) is given by
and that of the facesheets is
The shear stiffness of the beam is given by
Therefore, the shear stiffness of the beam, which is equal to the shear stiffness of the core, is
A relation can be obtained between the bending and shear deflections by using the continuity of tractions between the core and the facesheets. If we equate the tractions directly we get
At both the facesheet-core interfaces n x = 1 {\displaystyle n_{x}=1} but at the top of the core n z = 1 {\displaystyle n_{z}=1} and at the bottom of the core n z = − 1 {\displaystyle n_{z}=-1} . Therefore, traction continuity at z = ± h {\displaystyle z=\pm h} leads to
The above relation is rarely used because of the presence of second derivatives of the shear deflection. Instead it is assumed that
which implies that
Using the above definitions, the governing balance equations for the bending moment and shear force are
We can alternatively express the above as two equations that can be solved for w {\displaystyle w} and w s {\displaystyle w_{s}} as
Using the approximations
where q {\displaystyle q} is the intensity of the applied load on the beam, we have
Several techniques may be used to solve this system of two coupled ordinary differential equations given the applied load and the applied bending moment and displacement boundary conditions.
Assuming that each partial cross section fulfills Bernoulli's hypothesis , the balance of forces and moments on the deformed sandwich beam element can be used to deduce the bending equation for the sandwich beam.
The stress resultants and the corresponding deformations of the beam and of the cross section can be seen in Figure 1. The following relationships can be derived using the theory of linear elasticity : [ 3 ] [ 4 ]
where
Superposition of the equations for the facesheets and the core leads to the following equations for the total shear force Q {\displaystyle Q} and the total bending moment M {\displaystyle M} :
We can alternatively express the above as two equations that can be solved for w {\displaystyle w} and γ {\displaystyle \gamma } , i.e.,
The bending behavior and stresses in a continuous sandwich beam can be computed by solving the two governing differential equations.
For simple geometries such as double span beams under uniformly distributed loads, the governing equations can be solved by using appropriate boundary conditions and using the superposition principle. Such results are listed in the standard DIN EN 14509:2006 [ 5 ] (Table E10.1). Energy methods may also be used to compute solutions directly.
The differential equation of sandwich continuous beams can be solved by the use of numerical methods such as finite differences and finite elements . For finite differences Berner [ 6 ] recommends a two-stage approach. After solving the differential equation for the normal forces in the cover sheets for a single span beam under a given load, the energy method can be used to expand the approach for the calculation of multi-span beams. Sandwich continuous beam with flexible cover sheets can also be laid on top of each other when using this technique. However, the cross-section of the beam has to be constant across the spans.
A more specialized approach recommended by Schwarze [ 4 ] involves solving for the homogeneous part of the governing equation exactly and for the particular part approximately. Recall that the governing equation for a sandwich beam is
If we define
we get
Schwarze uses the general solution for the homogeneous part of the above equation and a polynomial approximation for the particular solution for sections of a sandwich beam. Interfaces between sections are tied together by matching boundary conditions. This approach has been used in the open source code swe2 .
Results predicted by linear sandwich theory correlate well with the experimentally determined results. The theory is used as a basis for the structural report which is needed for the construction of large industrial and commercial buildings which are clad with sandwich panels . Its use is explicitly demanded for approvals and in the relevant engineering standards. [ 5 ]
Mohammed Rahif Hakmi and others conducted researches into numerical, experimental behavior of materials and fire and blast behavior of Composite material . He published multiple research articles:
Hakmi developed a design method, which had been recommended by the CIB Working Commission W056 Sandwich Panels, ECCS/CIB Joint Committee and has been used in the European recommendations for the design of sandwich panels (CIB, 2000). [ 15 ] [ 16 ] [ 17 ] | https://en.wikipedia.org/wiki/Sandwich_theory |
Sandy Munro is an automotive engineer who specializes in machine tools and manufacturing .
He started as a toolmaker at the Valiant Machine & Tool company – a General Motors supplier in Windsor . In 1978, he joined the Ford Motor Company where he improved methods of engine assembly.
In 1988, he started his own consultancy, Munro & Associates , in Troy, Michigan , specializing in lean design , tearing down automotive products to study and suggest improvements and innovations . [ 1 ] [ 2 ] Now located in Auburn Hills, Michigan , the company performs electric vehicle benchmarking and consults in the aerospace, defense and medical sectors. [ 3 ]
In 2018, he started broadcasting video analyses and interviews on his YouTube channel, Munro Live . The channel has over 425,000 subscribers and raised the profile of his consultancy during the COVID-19 pandemic , when meetings and trade shows were restricted.
Munro was born on 19. January 1949 and grew up in Windsor, Ontario , Canada. Munro said he first started working by picking tomatoes at age 9. [ 4 ] He started his engineering career as a toolmaker at the Valiant Machine & Tool company which mainly supplied General Motors . He then joined Ford in 1978 where he became a manufacturing engineer and coordinator, improving methods of engine assembly. He then started his own consultancy in Troy, Michigan in 1988 and now has dual Canadian-US citizenship . [ 5 ] [ 6 ] [ 7 ]
Munro's consultancy specialises in deconstructing automobiles and has analysed the construction of hundreds of vehicles. The detailed analyses are sold to manufacturers and suppliers who use the information to help plan, price and improve their products. For example, they studied the BMW i3 in 2015 – an innovative electric car which made extensive use of carbon composites and hemp . Their detailed cost analysis cost $2.1 million to produce and originally sold for $89,000. [ 8 ] The report was 23,793 pages long, divided into the following sections: [ 9 ]
In 2020, the report was made available to the public as a sample of their work. Sandy Munro also hoped that this might inspire a future engineer, as he had been impressed when he was an apprentice and a retiring engineer had made the bargain offer of his expensive toolkit for just a "buck a drawer". [ 8 ]
Other electric cars analysed include the Chevrolet Bolt , Jaguar I-Pace , Tesla Model 3 and Tesla Model Y . They initially found that the Tesla cars had innovative and unusual electronics and power engineering but poor bodywork and production design. [ 10 ]
Munro & Associates consulted on the production design for several electrical vehicles including the Aptera three wheeled autocycle. [ 11 ] [ 12 ]
Munro advises and consults on the implementation and use of manufacturing methodologies including Design for Manufacture and Assembly (DFMA) and lean design . He introduced DFMA to Ingersoll Rand in 1989. [ 13 ] Munro's main design principles are: [ 14 ]
Sandy Munro gained larger public interest starting in February 2018 with videos containing detailed tear-down and analysis of the then-new Tesla Model 3 . Munro & Associates then started their own channel, Munro Live, with tear-down and analysis of a variety of mostly electric vehicles and covering related topics around engineering and design methodologies. This channel attracted lots of viewers which raised the profile of the company which was then able to expand its staff and premises despite the lockdowns and restrictions of the pandemic . [ 11 ]
In 2021, Munro recorded and published an interview with Tesla, Inc. CEO Elon Musk . They discussed the production of Tesla automobiles, including details such as the use of large castings in place of assemblies and the in-house design and production of the seats . In its first year, this interview received over three million views on YouTube . [ 15 ] [ 16 ] | https://en.wikipedia.org/wiki/Sandy_Munro |
The Sanford–Wang parameterisation is an empirical formula used to model the production of pions in nuclear interaction of the form p+A → π + {\displaystyle \pi ^{+}} +X where a beam of high-energy protons hit a material.
Its formula for the double-differential cross section with respect to momentum (p) and solid angle ( Ω {\displaystyle \Omega } ) is as follows.
d 2 σ ( p + A → π + + X ) d p d Ω ( p , θ ) = {\displaystyle {\frac {d^{2}\sigma (p+A\rightarrow \pi ^{+}+X)}{dpd\Omega }}(p,\theta )=} c 1 p c 2 ( 1 − p p b e a m ) exp [ − c 3 p c 4 p b e a m c 5 − c 6 θ ( p − c 7 p b e a m ( cos θ ) c 8 ) ] {\displaystyle c_{1}p^{c_{2}}\left(1-{\frac {p}{p_{beam}}}\right)\exp \left[-c_{3}{\frac {p^{c_{4}}}{p_{beam}^{c_{5}}}}-c_{6}\theta (p-c_{7}p_{beam}(\cos \theta )^{c_{8}})\right]}
Where p and θ {\displaystyle \theta } are the momentum of the outgoing pion and its angle from the direction of the incident proton. The numbers c 1 … c 8 {\displaystyle c_{1}\ldots c_{8}} are the Sanford-Wang parameters and are typically varied to give a good fit with experimental data. | https://en.wikipedia.org/wiki/Sanford–Wang_parameterisation |
Sangaku or san gaku ( Japanese : 算額 , lit. 'calculation tablet') are Japanese geometrical problems or theorems on wooden tablets which were placed as offerings at Shinto shrines or Buddhist temples during the Edo period by members of all social classes.
The sangaku were painted in color on wooden tablets ( ema ) and hung in the precincts of Buddhist temples and Shinto shrines as offerings to the kami and buddhas, as challenges to the congregants, or as displays of the solutions to questions. Many of these tablets were lost during the period of modernization that followed the Edo period, but around nine hundred are known to remain.
Fujita Kagen (1765–1821), a Japanese mathematician of prominence, published the first collection of sangaku problems, his Shimpeki Sampo (Mathematical problems Suspended from the Temple) in 1790, and in 1806 a sequel, the Zoku Shimpeki Sampo .
During this period Japan applied strict regulations to commerce and foreign relations for western countries so the tablets were created using Japanese mathematics , developed in parallel to western mathematics. For example, the connection between an integral and its derivative (the fundamental theorem of calculus ) was unknown, so sangaku problems on areas and volumes were solved by expansions in infinite series and term-by-term calculation.
(See also Ford circle .) | https://en.wikipedia.org/wiki/Sangaku |
Sanger sequencing is a method of DNA sequencing that involves electrophoresis and is based on the random incorporation of chain-terminating dideoxynucleotides by DNA polymerase during in vitro DNA replication . After first being developed by Frederick Sanger and colleagues in 1977, it became the most widely used sequencing method for approximately 40 years. An automated instrument using slab gel electrophoresis and fluorescent labels was first commercialized by Applied Biosystems in March 1987. [ 1 ] Later, automated slab gels were replaced with automated capillary array electrophoresis. [ 2 ]
Recently, higher volume Sanger sequencing has been replaced by next generation sequencing methods, especially for large-scale, automated genome analyses. However, the Sanger method remains in wide use for smaller-scale projects and for validation of deep sequencing results. It still has the advantage over short-read sequencing technologies (like Illumina) in that it can produce DNA sequence reads of > 500 nucleotides and maintains a very low error rate with accuracies around 99.99%. [ 3 ] Sanger sequencing is still actively being used in efforts for public health initiatives such as sequencing the spike protein from SARS-CoV-2 [ 4 ] as well as for the surveillance of norovirus outbreaks through the United States Center for Disease Control and Prevention (CDC) 's CaliciNet surveillance network. [ 5 ]
The classical chain-termination method requires a single-stranded DNA template, a DNA primer , a DNA polymerase , normal deoxynucleotide triphosphates ( dNTPs ), and modified di-deoxynucleotide triphosphates ( ddNTPs ), the latter of which terminate DNA strand elongation. These chain-terminating nucleotides lack a 3'- OH group required for the formation of a phosphodiester bond between two nucleotides, causing DNA polymerase to cease extension of DNA when a modified ddNTP is incorporated. The ddNTPs may be radioactively or fluorescently labelled for detection in automated sequencing machines.
The DNA sample is divided into four separate sequencing reactions, containing all four of the standard deoxynucleotides (dATP, dGTP, dCTP and dTTP) and the DNA polymerase. To each reaction is added only one of the four dideoxynucleotides (ddATP, ddGTP, ddCTP, or ddTTP), while the other added nucleotides are ordinary ones. The deoxynucleotide concentration should be approximately 100-fold higher than that of the corresponding dideoxynucleotide (e.g. 0.5mM dTTP : 0.005mM ddTTP) to allow enough fragments to be produced while still transcribing the complete sequence (but the concentration of ddNTP also depends on the desired length of sequence). [ 6 ] Putting it in a more sensible order, four separate reactions are needed in this process to test all four ddNTPs. Following rounds of template DNA extension from the bound primer, the resulting DNA fragments are heat denatured and separated by size using gel electrophoresis . In the original publication of 1977, [ 6 ] the formation of base-paired loops of ssDNA was a cause of serious difficulty in resolving bands at some locations. This is frequently performed using a denaturing polyacrylamide -urea gel with each of the four reactions run in one of four individual lanes (lanes A, T, G, C). The DNA bands may then be visualized by autoradiography or UV light, and the DNA sequence can be directly read off the X-ray film or gel image.
In the image on the right, X-ray film was exposed to the gel, and the dark bands correspond to DNA fragments of different lengths. A dark band in a lane indicates a DNA fragment that is the result of chain termination after incorporation of a dideoxynucleotide (ddATP, ddGTP, ddCTP, or ddTTP). The relative positions of the different bands among the four lanes, from bottom to top, are then used to read the DNA sequence.
Technical variations of chain-termination sequencing include tagging with nucleotides containing radioactive phosphorus for radiolabelling , or using a primer labeled at the 5' end with a fluorescent dye. Dye-primer sequencing facilitates reading in an optical system for faster and more economical analysis and automation. The later development by Leroy Hood and coworkers [ 7 ] [ 8 ] of fluorescently labeled ddNTPs and primers set the stage for automated, high-throughput DNA sequencing.
Chain-termination methods have greatly simplified DNA sequencing. For example, chain-termination-based kits are commercially available that contain the reagents needed for sequencing, pre-aliquoted and ready to use. Limitations include non-specific binding of the primer to the DNA, affecting accurate read-out of the DNA sequence, and DNA secondary structures affecting the fidelity of the sequence.
Dye-terminator sequencing utilizes labelling of the chain terminator ddNTPs, which permits sequencing in a single reaction rather than four reactions as in the labelled-primer method. In dye-terminator sequencing, each of the four dideoxynucleotide chain terminators is labelled with fluorescent dyes, each of which emits light at different wavelengths .
Owing to its greater expediency and speed, dye-terminator sequencing is now the mainstay in automated sequencing. Its limitations include dye effects due to differences in the incorporation of the dye-labelled chain terminators into the DNA fragment, resulting in unequal peak heights and shapes in the electronic DNA sequence trace electropherogram (a type of chromatogram ) after capillary electrophoresis (see figure to the left).
This problem has been addressed with the use of modified DNA polymerase enzyme systems and dyes that minimize incorporation variability, as well as methods for eliminating "dye blobs". The dye-terminator sequencing method, along with automated high-throughput DNA sequence analyzers, was used for the vast majority of sequencing projects until the introduction of next generation sequencing .
Automated DNA-sequencing instruments ( DNA sequencers ) can sequence up to 384 DNA samples in a single batch. Batch runs may occur up to 24 times a day. DNA sequencers separate strands by size (or length) using capillary electrophoresis , they detect and record dye fluorescence, and output data as fluorescent peak trace chromatograms . Sequencing reactions ( thermocycling and labelling), cleanup and re-suspension of samples in a buffer solution are performed separately, before loading samples onto the sequencer. A number of commercial and non-commercial software packages can trim low-quality DNA traces automatically. These programs score the quality of each peak and remove low-quality base peaks (which are generally located at the ends of the sequence). [ 9 ] The accuracy of such algorithms is inferior to visual examination by a human operator, but is adequate for automated processing of large sequence data sets.
The field of public health plays many roles to support patient diagnostics as well as environmental surveillance of potential toxic substances and circulating biological pathogens. Public health laboratories (PHL) and other laboratories around the world have played a pivotal role in providing rapid sequencing data for the surveillance of the virus SARS-CoV-2 , causative agent for COVID-19, during the pandemic that was declared a public health emergency on January 30, 2020. [ 10 ] Laboratories were tasked with the rapid implementation of sequencing methods and asked to provide accurate data to assist in the decision-making models for the development of policies to mitigate spread of the virus. Many laboratories resorted to next generation sequencing methodologies while others supported efforts with Sanger sequencing. The sequencing efforts of SARS-CoV-2 are many, while most laboratories implemented whole genome sequencing of the virus, others have opted to sequence very specific genes of the virus such as the S-gene, encoding the information needed to produce the spike protein. The high mutation rate of SARS-CoV-2 leads to genetic differences within the S-gene and these differences have played a role in the infectivity of the virus. [ 11 ] Sanger sequencing of the S-gene provides a quick, accurate, and more affordable method to retrieving the genetic code. Laboratories in lower income countries may not have the capabilities to implement expensive applications such as next generation sequencing, so Sanger methods may prevail in supporting the generation of sequencing data for surveillance of variants.
Sanger sequencing is also the "gold standard" for norovirus surveillance methods for the Center for Disease Control and Prevention's (CDC) CaliciNet network. CalciNet is an outbreak surveillance network that was established in March 2009. The goal of the network is to collect sequencing data of circulating noroviruses in the United States and activate downstream action to determine the source of infection to mitigate the spread of the virus. The CalciNet network has identified many infections as foodborne illnesses. [ 5 ] This data can then be published and used to develop recommendations for future action to prevent tainting food. The methods employed for detection of norovirus involve targeted amplification of specific areas of the genome. The amplicons are then sequenced using dye-terminating Sanger sequencing and the chromatograms and sequences generated are analyzed with a software package developed in BioNumerics . Sequences are tracked and strain relatedness is studied to infer epidemiological relevance.
Common challenges of DNA sequencing with the Sanger method include poor quality in the first 15–40 bases of the sequence due to primer binding and deteriorating quality of sequencing traces after 700–900 bases. Base calling software such as Phred typically provides an estimate of quality to aid in trimming of low-quality regions of sequences. [ 12 ] [ 13 ]
In cases where DNA fragments are cloned before sequencing, the resulting sequence may contain parts of the cloning vector . In contrast, PCR -based cloning and next-generation sequencing technologies based on pyrosequencing often avoid using cloning vectors. Recently, one-step Sanger sequencing (combined amplification and sequencing) methods such as Ampliseq and SeqSharp have been developed that allow rapid sequencing of target genes without cloning or prior amplification. [ 14 ] [ 15 ]
Current methods can directly sequence only relatively short (300–1000 nucleotides long) DNA fragments in a single reaction. The main obstacle to sequencing DNA fragments above this size limit is insufficient power of separation for resolving large DNA fragments that differ in length by only one nucleotide.
Microfluidic Sanger sequencing is a lab-on-a-chip application for DNA sequencing, in which the Sanger sequencing steps (thermal cycling, sample purification, and capillary electrophoresis) are integrated on a wafer-scale chip using nanoliter-scale sample volumes. This technology generates long and accurate sequence reads, while obviating many of the significant shortcomings of the conventional Sanger method (e.g. high consumption of expensive reagents, reliance on expensive equipment, personnel-intensive manipulations, etc.) by integrating and automating the Sanger sequencing steps.
In its modern inception, high-throughput genome sequencing involves fragmenting the genome into small single-stranded pieces, followed by amplification of the fragments by polymerase chain reaction (PCR). Adopting the Sanger method, each DNA fragment is irreversibly terminated with the incorporation of a fluorescently labeled dideoxy chain-terminating nucleotide, thereby producing a DNA “ladder” of fragments that each differ in length by one base and bear a base-specific fluorescent label at the terminal base. Amplified base ladders are then separated by capillary array electrophoresis (CAE) with automated, in situ “finish-line” detection of the fluorescently labeled ssDNA fragments, which provides an ordered sequence of the fragments. These sequence reads are then computer assembled into overlapping or contiguous sequences (termed "contigs") which resemble the full genomic sequence once fully assembled. [ 16 ]
Sanger methods achieve maximum read lengths of approximately 800 bp (typically 500–600 bp with non-enriched DNA). The longer read lengths in Sanger methods display significant advantages over other sequencing methods especially in terms of sequencing repetitive regions of the genome. A challenge of short-read sequence data is particularly an issue in sequencing new genomes (de novo) and in sequencing highly rearranged genome segments, typically those seen of cancer genomes or in regions of chromosomes that exhibit structural variation. [ 17 ]
Other useful applications of DNA sequencing include single nucleotide polymorphism (SNP) detection, single-strand conformation polymorphism (SSCP) heteroduplex analysis , and short tandem repeat (STR) analysis. Resolving DNA fragments according to differences in size and/or conformation is the most critical step in studying these features of the genome. [ 16 ]
The sequencing chip has a four-layer construction, consisting of three 100-mm-diameter glass wafers (on which device elements are microfabricated) and a polydimethylsiloxane (PDMS) membrane. Reaction chambers and capillary electrophoresis channels are etched between the top two glass wafers, which are thermally bonded. Three-dimensional channel interconnections and microvalves are formed by the PDMS and bottom manifold glass wafer.
The device consists of three functional units, each corresponding to the Sanger sequencing steps. The thermal cycling (TC) unit is a 250-nanoliter reaction chamber with integrated resistive temperature detector, microvalves, and a surface heater. Movement of reagent between the top all-glass layer and the lower glass-PDMS layer occurs through 500-μm-diameter via-holes. After thermal-cycling, the reaction mixture undergoes purification in the capture/purification chamber, and then is injected into the capillary electrophoresis (CE) chamber. The CE unit consists of a 30-cm capillary which is folded into a compact switchback pattern via 65-μm-wide turns.
The Apollo 100 platform (Microchip Biotechnologies Inc., Dublin, California) [ 18 ] integrates the first two Sanger sequencing steps (thermal cycling and purification) in a fully automated system. The manufacturer claims that samples are ready for capillary electrophoresis within three hours of the sample and reagents being loaded into the system. The Apollo 100 platform requires sub-microliter volumes of reagents.
The ultimate goal of high-throughput sequencing is to develop systems that are low-cost, and extremely efficient at obtaining extended (longer) read lengths. Longer read lengths of each single electrophoretic separation, substantially reduces the cost associated with de novo DNA sequencing and the number of templates needed to sequence DNA contigs at a given redundancy. Microfluidics may allow for faster, cheaper and easier sequence assembly. [ 16 ] | https://en.wikipedia.org/wiki/Sanger_sequencing |
Sanger–Black apparatus [ 1 ] is a piece of chemical laboratory ware used for quantitative and semi-quantitative determination of arsenic element in the solution. It is constituted by glass bottle of volume ca. 30 mL, sealed with rubber stopper with one or two holes. Through one hole a thistle tube is inserted, almost reaching the bottom, for filling the bottle (what can be done also when the stopper is taken out – for semi-quantitative determination). The second, S-shaped tube is for outflow of the gases and joined by another rubber stopper to a bulg tube, with bulb containing pre-dried cotton as adsorbent, presumably intended for homogenizing the gas flow. A thin reagent paper, impregnated with mercury(II) chloride (nowadays replaced by mercury(II) bromide) [ 2 ] or silver(I) nitrate , is placed in the open end of the bulb tube. If the semi-quantitative variant is to be performed, the paper is put in the (only) thistle tube – i. e., vertically, not horizontally. During the test ca. 3 g of Zn granules are placed into the bottle, just below the end of thistle tube, and then acid solution is added (ca. 15 mL; authors recommend that HCl is preferable to H 2 SO 4 ). About 10 minutes are required to let H 2 flow along the reagent paper, while this flow and moisture content inside it is stabilizing. Then the sample is introduced, and in case of sample solution containing arsenic the paper becomes more or less stained. [ 1 ]
The Sanger–Black determination is based on the so-called Gutzeit reaction (1879): [ 2 ] [ 3 ]
AsH 3 is forming from arsenic in any oxidation state when it reduces with the hydrogen in statu nascendi , produced from the acid. [ 2 ] [ 4 ] Gutzeit originally used AgNO 3 for determination. [ 2 ] The innovation to the Gutzeit method by Sanger and Black is the use of long and narrow paper, so that gas flow is directed along it and the product of reaction used as analytic signal deposits almost uniquely in the surface layers of the paper, so that stain area is quantitative analytic signal (if all the prerequisites for determination are fulfilled). [ 1 ] Unfortunately, yellow colour is not that human eye is especially sensitive for, so photometric tools were introduced for quantitative analysis quite a long time ago (in 1944). [ 2 ] [ 5 ]
Zinc naturally contains some trace amounts of arsenic, [ 2 ] so a modest yellow stain appears almost in any case on the reagent paper. This limits the sensitivity of this test, as arsenic amounts in zinc vary from one supplier to another. That is why later Zn was replaced by sodium borohydride NaBH 4 ; then, strong and corrosive hydrochloric acid was also replaced with sulfamic acid NH 2 SO 3 H. [ 2 ] | https://en.wikipedia.org/wiki/Sanger–Black_apparatus |
Sanitary engineering or sanitation engineering , also known as public health engineering or wastewater engineering , is the application of engineering methods to improve sanitation of human communities, primarily by providing the removal and disposal of human waste, and in addition to the supply of safe potable water . Traditionally a branch of civil engineering and now a subset of building services engineering and environmental engineering , in the mid-19th century, the discipline concentrated on the reduction of disease, then thought to be caused by miasma . This was accomplished mainly by the collection and segregation of sewerage flow in London specifically, and Great Britain generally. [ 1 ] These and later regulatory improvements were reported in the United States as early as 1865. [ 2 ]
It is also concerned with environmental factors that do not have an immediate and clearly understood effect on public health. Areas outside the purview of sanitary engineering include aesthetic concerns such as landscaping , and environmental conservation as it pertains to plants and animals .
Skills within this field are usually employed for the primary goal of disease prevention within human beings by assuring a supply of healthy drinking water , treatment of waste water, and removal of garbage from inhabited areas.
Compared to (for example) electrical engineering or mechanical engineering which are concerned primarily with closed systems , sanitary engineering is a very interdisciplinary field which may involve such elements as plumbing , fire protection , hydraulics , life safety, constructive modelling, information technology , project design, microbiology , pathology and the many divisions within environmental science and environmental technology . In some cases, considerations that fall within the field of social sciences and urban planning must be factored in as well.
Although sanitary engineering may be most associated with the design of sewers , sewage treatment and wastewater treatment facilities, recycling centers, public landfills and other things which are constructed, the term applies equally to a plan of action to reverse the effects of water pollution or soil contamination in a specific area.
Irrigation systems were invented five to seven thousand years ago as a means of supplying water to agriculture-based societies. Aqueducts and irrigation systems were among the first forms of wastewater engineering. As population centers became more dense, they were used to remove sewage from settlements. The Romans were among the first to demonstrate the effectiveness of the aqueduct. The Dark Ages marked a period where progress in water management came to a halt. [ 3 ]
As populations grew, the management of human waste became a growing concern and a public health threat. By the 1850s in London, more than 400,000 tons of sewage were flushed into the River Thames each day - around 150 million tons per year. [ 4 ] Diseases such as smallpox , diphtheria , measles , scarlet fever , typhus , cholera , and typhoid were spread via the contaminated water supply. [ 5 ] During the 19th century, major cities started building sewage systems to remove human waste out of cities and into rivers.
During the 1900s, the activated sludge process was invented. [ 6 ] The activated sludge process is a form of water purification that uses bacteria to consume human feces. Chlorine is used later in the process to kill off the bacteria. In the 1950s, the public health reports provided plans for supplying clean water for the public by first looking at potential hazards. The organization looked carefully at water contamination as well as how drinking water was being treated. They also prioritized finding methods that were effective, yet not too costly. [ 7 ] Sanitation cost is the main issue for many foreign (not the United States) countries. The average cost of home water and sanitation systems start at $50 a month, when many citizens don't make enough money to use on non-necessities. [ 8 ]
Over the centuries, much has changed in the field of wastewater engineering. Advancements in microbiology, chemistry, and engineering have drastically changed the field. Today, wastewater engineers also work on the collection of clean water for drinking, chemically treating it, and using UV light to kill off micro-organisms. They also treat water pollution in wastewater ( blackwater and greywater ) so that this water may be made safe for use without endangering the population and environment around it. Wastewater treatment and water reclamation are areas of concern in this field.
Prior to modern forms of sanitation in neighborhoods and cities, people would simply leave their trash on the street. In 1892, it was such an issue, that a man named Harm Huizenga volunteered to clean up the mess by himself. The Dutch man went around the streets in his wagon, picking up the garbage of the city of Chicago. Little efforts like that were present throughout the early 1900s, until around 1968. Huizenga's grandson, Wayne Huizenga, made his grandfather's idea into a business, Waste Management. By the seventies, waste management as a whole was seen as a necessary practice by the public. [ 9 ]
In the early 1940s, many counties in the state had problems with their disposal of waste, especially in the Lake Tahoe area. Citizens of these towns feared that their city's poor sewage systems would cause outbreaks in illnesses, like poliomyelitis , cholera , and hepatitis , to name a few. Cholera in particular is the biggest health risk attached to waste management. The illness is caused by bacteria, especially when a person ingests food or water that contain the bacteria. In poorer areas, this is extremely likely due to the cross contamination of waste and drinking water.
Wastewater engineering is not usually its own degree course, but a specialization from degrees such as environmental and sanitary engineering, sanitary engineering, civil engineering , environmental engineering , bio-chemical engineering, or chemical engineering . Formal education for wastewater engineers begins in high school with students taking classes such as chemistry, biology, physics, and higher mathematics including calculus. After high school most jobs require certification from a state agency. Those wanting to advance in the industry should pursue a sanitary engineering, environmental and sanitary engineering, civil engineering, mechanical engineering , environmental engineering, or a facilities engineering degree. Gaining experience through internships and working while in college is a common pathway toward advancement.
Education about waste treatment requires course work in systems design, machinery design principles, water chemistry, and similar coursework. Other classes may include Chemistry of Plant Processes, and various plant operations courses.
Wastewater engineers may advance in their careers through additional education and experience. With additional knowledge and experience one can become the manager of an entire plant. The accreditation body certifying the education for the degree and license is the Accreditation Board for Engineering and Technology (ABET). Over time, some companies may require the wastewater engineer to continue their education to keep up with any changes in technology.
Obtaining one's master's degree is encouraged since many companies list it as a preference in selection. [ 12 ] [ 13 ]
In this field 76 percent of those employed have a bachelor's degree, 17 percent have a master's degree and three percent have a post-doctoral degree as of 2013. [ 14 ] The average annual salary is approximately $83,360. [ 15 ]
Initial employment in wastewater engineering can be obtained by those with and without advanced formal education. The California State Water Resources Control Board (SWRCB), for example, shows how individuals can advance through a progression of certifications as Waste Water Treatment Operators. [ 16 ] The Board uses a five level classification system to classify water treatment facilities into categories I-V according to the population served and the complexity of the treatment system. [ citation needed ]
The Operator Certification requirements for water treatment operators and waste water treatment operators are described in detail by State law. To meet certification requirements, operators must submit an application to SWRCB, have the necessary work experience, meet the educational requirements, and pass an examination based on the knowledge, skill, and abilities described in the regulations. Operators are required to renew their certificates every three years. To be eligible for renewal, certified operators must complete a specified number of continuing education hours after the previous issuance of a certificate. [ 17 ]
Important job types working in sanitary engineering include sanitation workers , waste collectors and wastewater engineers. [ citation needed ]
Wastewater engineers use a variety of skills and must have knowledge of mechanical and environmental engineering. They are required to perform tasks and demonstrate knowledge in design, mathematics, English, construction, physics, chemistry, biology, management, and personnel. Wastewater engineers must have skills in complex problem solving, critical thinking, mathematics, active listening, judgement, reading comprehension, speaking, writing, science, and system analysis. [ 14 ] Typical work activities include problem solving, communication with management and staff, gathering information, analyzing data, evaluating standards and complying with them, and communicating with others in the field. [ citation needed ]
Wastewater engineers perform these activities by combining their knowledge and skills to perform tasks. These tasks are to understand computer-aided design programs, and to conduct studies for the construction of facilities, water supply systems and collection systems. They may design systems for wastewater collection machinery, as well as system components. They may perform water flow analysis, then select designs and equipment based on government and industry standards. [ 18 ] Some are involved with a specific area of concern such as waste collection or the maintenance of waste water facilities and stormwater drainage systems within an area. Others cover a broader scope of activities that might include maintenance of the public water supply , collection of residential yard waste program, disposal of hazardous waste , recycling strategies and even community programs where individuals or businesses "adopt" an area and either maintain it themselves or donate funds for doing so. [ citation needed ]
Wastewater engineers may also map out topographical and geographical features of Earth to determine the best means of collection, design pipe and pumped collection systems, and design treatment processes for collected wastewater. [ citation needed ]
Wastewater engineers work for private companies, state and local governments, and special districts.
Water managers confront new challenges and the need for new technology as water levels decrease due to increasingly frequent and extended droughts. Technologies such as sonar mapping are being used in wells to determine the volume of water that they can hold. For example, the United States Geological Survey and the State of New York worked together to map underground aquifers since the 1980s. [ 19 ] Today they have thorough maps of these aquifers to assist in water management.
Desalination plants may be required in the future for those regions hardest hit by water scarcity . Desalination is a process of cleaning water by means of evaporation. Water is evaporated and it passes through membranes. The water is then cooled and condenses allowing it to flow either back into the main water line or out to sea. [ 20 ]
Smart Sanitation: Advances in sensor technology, data analytics, and automation are enabling the development of smart sanitation systems that can monitor water quality, detect leaks, optimize treatment processes, and improve overall efficiency. Sanitary engineers need to leverage these technologies to enhance the performance and reliability of sanitation infrastructure. [ 21 ]
Wastewater treatment contributes to global warming in many ways. One of the factors that contributes to global warming is wastewater treatment facilities and their emissions of greenhouse gases . Some of those gases are carbon dioxide, methane, and nitrous oxide . These gases occur because of the decomposition of organic material from the anaerobic bacteria. These bacteria clean the leftover waste. Even if the anaerobic bacteria decomposition produces these gases, the percentage of greenhouse gases that other equipment produce is still greater than the contribution of the anaerobic bacteria. Also, the power usage from those machinery is very high. That is why many facilities are undergoing renovation to use higher levels of anaerobic bacteria compared to other types of equipment. [ 22 ]
Impacts of climate change on sanitary engineering vary based on region and the sanitation solutions employed there. In the Arctic, permafrost melting has caused damage to pipes and other infrastructure. [ 23 ] In the Northeastern United States, increased precipitation has overwhelmed aging infrastructure not equipped to handle the massive volume of water from heavy precipitation. [ 24 ] In the Western United States, prolonged drought has decreased water availability. This has led some wastewater facilities to expand recycled and reclaimed water programs. [ 25 ] Climate change has also affected water distribution pipes. Physical stress from climate change-related conditions such as extreme rainfall or drought increases the rate of pipe corrosion, adding to facility cost. [ 26 ] | https://en.wikipedia.org/wiki/Sanitary_engineering |
Sanitary epidemiological reconnaissance , synonym epidemiological reconnaissance is a literal name of a concept and routine of finding out disease potential on a territory of arrival of major contingent. Russian : санитарно-эпидемиологическая разведка, син. эпидемиологическая разведка . [ 1 ] [ 2 ] This is a kind of medical reconnaissance , process of information gathering on possible infectious diseases' origin-sources, the ways and factors of the infection transfer and determining all conditions that could have promoted the spread of infestation among army service personnel. [ 3 ] [ 4 ] In 1939 Academician E.N.Pavlovsky announced his "doctrine of nidality", so called by Soviet biologists. [ 5 ] People can acquire zoonoses and insect-borne diseases when they occupy at certain times of the year natural habitat of a certain pathogen (e.g., plague , tularemia , leptospirosis , arboviruses , tick-borne relapsing fever). The WHO Expert Committee on Zoonoses listed over 100 such diseases. [ 6 ] [ 7 ] About natural focality of the diseases is known elsewhere. [ 8 ]
Historically, Sanitary epidemiological reconnaissance implied collection and transfer of all data available on sanitary and epidemiological situation of the area of possible deployment and action of armed forces , the same data for the neighbouring and enemy armed forces. The aim for the reconnaissance was to clear up the reasons of the specific disease origin—sources of the infection in various extreme situations, including local wars and armed conflicts , the ways of the infection transfer and all factors promoting to the infestation .
This practice has been successfully used on plague -endemic territory at the time of the Soviet–Japanese War (1945) in WWII : "Sanitary epidemiological reconnaissance was organized and conducted continuously for the entire depth of the operation. Mobile sanitary epidemiological detachments followed immediately behind the first echelon of tanks and mechanized vehicles of advancing Soviet army should they encounter any particular contagious disease . Withdrawing enemy forces had poisoned many wells and water sources". [ 9 ] After the armed forces have become stationary during wartime and emergency of peace time the sanitary epidemiological reconnaissance turns into sanitary and epidemiological surveillance and medical control of vital and communal activity of the armed forces. [ 10 ] [ 11 ]
Sanitary epidemiological reconnaissance as a practice has nothing in common with the Epidemic Intelligence Service as an educational program of the United States' Centers for Disease Control and Prevention (CDC). The latter was established in 1951 by Alexander Langmuir , due to biological warfare concerns arising from the Korean War , it has become a hands-on two-year postgraduate training program in epidemiology . [ citation needed ]
The use of sanitary epidemiological reconnaissance or similar practices in the armed forces is mentioned elsewhere. [ 12 ] The Polish contingents serving under the UN auspices focused their tasks among others on ... sanitary-epidemiological reconnaissance ... . [ 13 ] The similar practice is recognized by the WHO and Australia while encompassing chemical, radiological hazards as well. [ 14 ] They call it "All-hazards approach" [ 15 ] US Department of Health and Human Services in the page 300 of its manual in [ 16 ] admits existence of other surveillance systems calling them "early-warning systems of disease potential" with the aim to collect data on indicators of disease or disease potential: animal population (animal morbidity and mortality by a disease that can affect humans, the presence of a disease agent in wild and domestic sentinel animals, vectors of a disease) and environmental data. [ citation needed ]
There is a definite need in mobile sanitary-epidemiological groups, trained and equipped for the task. Any group for sanitary epidemiological reconnaissance includes: epidemiologist , specialist on infections, assistant of epidemiologist ( bacteriologist - lab assistant ), medical orderly (if necessary, the group will include zoologist or parasitologist ). These units should be formed up in the deployable medical set-ups. [ 17 ] Sanitary-epidemiological reconnaissance should result in revealing of the patients and persons, suspected to the specific disease, their isolation and hospitalization.
A sanitary-epidemiological kit is constructed, consisting of two separate units, but each adaptable to use with the other: a portable laboratory kit and a portable combination lab apparatus. The two units can be useful in the work of epidemiologists during sanitary-epidemiological reconnaissance and sanitary epidemiological surveys. [ 18 ]
In 2010 at The Meeting of the States Parties to the Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and Their Destruction in Geneva [ 19 ] the sanitary epidemiological reconnaissance was suggested as well-tested means for enhancing the monitoring of infections and parasitic agents, for practical implementation of the International Health Regulations (2005). The aim was to prevent and minimize the consequences of natural outbreaks of dangerous infectious diseases as well as the threat of alleged use of biological weapons against BTWC States Parties. It is pointed out the significance of the sanitary epidemiological reconnaissance in assessing the sanitary-epidemiological situation, organizing and conducting preventive activities, indicating and identifying pathogenic biological agents in the environmental sites, conducting laboratory analysis of biological materials, suppressing hotbeds of infectious diseases, providing advisory and practical assistance to local health authorities.
Sanitary epidemiological reconnaissance (inspection) or a similar practice and specific indication in the hotbed should be performed immediately after the receiving of the information about bio-terrorism attack. [ 20 ] [ 21 ]
There were compiled the principles of organization of sanitary epidemiological reconnaissance and criteria for evaluating the sanitary epidemiological status of arms force and regions of their dislocation. [ 22 ]
Langmuir , A D (1980). "The Epidemic Intelligence Service of the Center for Disease Control" . Public Health Reports . 95 (5): 470– 7. PMC 1422746 . PMID 6106957 . LANGMUIR, A D; ANDREWS J M (March 1952). "Biological warfare defense. 2. The Epidemic Intelligence Service of the Communicable Disease Center" . American Journal of Public Health and the Nation's Health . 42 (3): 235– 8. doi : 10.2105/AJPH.42.3.235 . PMC 1526024 . PMID 14903237 . | https://en.wikipedia.org/wiki/Sanitary_epidemiological_reconnaissance |
A sanitary sewer is an underground pipe or tunnel system for transporting sewage from houses and commercial buildings (but not stormwater ) to a sewage treatment plant or disposal.
Sanitary sewers are a type of gravity sewer and are part of an overall system called a "sewage system" or sewerage . Sanitary sewers serving industrial areas may also carry industrial wastewater . In municipalities served by sanitary sewers, separate storm drains may convey surface runoff directly to surface waters. An advantage of sanitary sewer systems is that they avoid combined sewer overflows . Sanitary sewers are typically much smaller in diameter than combined sewers which also transport urban runoff . Backups of raw sewage can occur if excessive stormwater inflow or groundwater infiltration occurs due to leaking joints, defective pipes etc. in aging infrastructure.
Sewage treatment is less effective when sanitary waste is diluted with stormwater, and combined sewer overflows occur when runoff from heavy rainfall or snowmelt exceeds the hydraulic capacity of sewage treatment plants . [ 1 ] To overcome these disadvantages, some cities built separate sanitary sewers to collect only municipal wastewater and exclude stormwater runoff, which is collected in separate storm drains. The decision to build a combined sewer system or two separate systems is mainly based on the need for sewage treatment and the cost of providing treatment during heavy rain events. Many cities with combined sewer systems built their systems prior to installing sewage treatment plants, and have not subsequently replaced those sewer systems. [ 2 ]
In the developed world, sewers are pipes from buildings to one or more levels of larger underground trunk mains, which transport the sewage to sewage treatment facilities. Vertical pipes, usually made of precast concrete , called manholes , connect the mains to the surface. Depending upon site application and use, these vertical pipes can be cylindrical , eccentric , or concentric . The manholes are used for access to the sewer pipes for inspection and maintenance, and as a means to vent sewer gases. They also facilitate vertical and horizontal angles in otherwise straight pipelines. [ 4 ]
Pipes conveying sewage from an individual building to a common gravity sewer line are called laterals. Branch sewers typically run under streets receiving laterals from buildings along that street and discharge by gravity into trunk sewers at manholes. Larger cities may have sewers called interceptors , receiving flow from multiple trunk sewers. [ 5 ] [ 6 ]
Design and sizing of sanitary sewers considers the population to be served over the anticipated life of the sewer, per capita wastewater production, and flow peaking from timing of daily routines. Minimum sewer diameters are often specified to prevent blockage by solid materials flushed down toilets; gradients may be selected to maintain flow velocities generating sufficient turbulence to minimize solids deposition within the sewer. Commercial and industrial wastewater flows are also considered, but diversion of surface runoff to storm drains eliminates wet weather flow peaks of inefficient combined sewers. [ 7 ]
A force main or rising main [ 8 ] is a pumped sewer that may be necessary where gravity sewers serve areas at lower elevations than the sewage treatment plant, or distant areas at similar elevations. A lift station is a sewer sump that lifts accumulated sewage to a higher elevation. They may also be used to prime an inverted siphon used to cross underneath rivers or other obstructions. The pump may discharge to another gravity sewer or directly to a treatment plant. [ 6 ] Force mains are typically constructed of welded steel or HDPE jointed to resist pressures within the pipe. Force mains are substantially different from pressure sewers which serve individual properties or groups of properties and provide a means of injecting sewage into a local gravity main.
Effluent sewer systems, also called septic tank effluent drainage (STED) or solids-free sewer (SFS) systems, have septic tanks that collect sewage from residences and businesses, and the effluent that comes out of the tank is sent to either a centralized sewage treatment plant or a distributed treatment system for further treatment. Most of the solids are removed by the septic tanks, so the treatment plant can be much smaller than a typical plant. In addition, because of the vast reduction in solid waste, a pumping system, rather than a gravity system, can be used to move the wastewater. The pipes have small diameters, typically 1.5 to 4 inches (4 to 10 cm). Because the waste stream is pressurized, they can be laid just below the ground surface along the land's contour. [ citation needed ]
Where it is impossible or impractical to discharge sewage from a property into a gravity sanitary sewer, a pressure sewer may provide an alternative means of connection. A macerator pump in a pumping well close to the property ejects sewage through a small-diameter high-pressure pipe into the nearest gravity sewer. [ 9 ]
Simplified sanitary sewers consist of small-diameter pipes, typically around 100 millimetres (4 in), often laid at fairly flat gradients (1 in 200). Although the investment cost for simplified sanitary sewers can be about half the cost of conventional sewers, the requirements for operation and maintenance are usually higher. Simplified sewers are most common in Brazil and other developing countries. [ citation needed ]
In low-lying communities, wastewater is often conveyed by vacuum sewer . Pipelines range in size from pipes of 125 millimetres (4.9 in) in diameter up to 280 millimetres (11 in) in diameter. Vacuum sewer systems use differential atmospheric pressure to move the liquid to a central vacuum station. [ 10 ]
Sanitary sewer overflow can occur due to blocked or broken sewer lines, infiltration of excessive stormwater or malfunction of pumps. In these cases untreated sewage is discharged from a sanitary sewer into the environment prior to reaching sewage treatment facilities. To avoid such overflows, maintenance is required. Blockage prevention campaigns or regulations (e.g. requiring the use of grease interceptors by some customers) may also be necessary.
The maintenance requirements vary with the type of sanitary sewer. In general, all sewers deteriorate with age, but infiltration and inflow are problems unique to sanitary sewers, since both combined sewers and storm drains are sized to carry these contributions. Holding infiltration to acceptable levels requires a higher standard of maintenance than necessary for structural integrity considerations of combined sewers. [ 11 ] A comprehensive construction inspection program is required to prevent inappropriate connection of cellar, yard, and roof drains to sanitary sewers. [ 12 ] The probability of inappropriate connections is higher where combined sewers and sanitary sewers are found in close proximity, because construction personnel may not recognize the difference. Many older cities still use combined sewers while adjacent suburbs were built with separate sanitary sewers.
For decades, when sanitary sewer pipes cracked or experienced other damage, the only option was an expensive excavation, removal and replacement of the damaged pipe, typically requiring street repavement afterwards. In the mid-1950s a unit was invented where two units at each end with a special cement mixture in between was pulled from one manhole cover to the next, coating the pipe with the cement under high pressure, which then cured rapidly , sealing all cracks and breaks in the pipe. [ 13 ] Today, a similar method using epoxy resin is used by some municipalities to re-line aging or damaged pipes, effectively creating a "pipe in a pipe". These methods may be unsuitable for locations where the full diameter of the original pipe is required to carry expected flows, and may be an unwise investment if greater wastewater flows may be anticipated from population growth, increased water use, or new service connections within the expected service life of the repair.
Another popular method for replacing aged or damaged lines is called pipe bursting , where a new pipe, typically PVC or ABS plastic, is drawn through the old pipe behind an "expander head" that breaks apart the old pipe as the new one is drawn through behind it.
These methods are most suitable for trunk sewers, since repair of lines with lateral connections is complicated by making provisions to receive lateral flows without accepting undesirable infiltration from inadequately sealed junctions.
Some sewers have tall vent pipes to release foul gases well up away from people. Common names for these pipes are stink pipe, stink pole, stench pipe and sewer ventilation pipe. [ 14 ]
Sanitary sewers evolved from combined sewers built where water was plentiful. Animal feces accumulated on city streets while animal-powered transport moved people and goods. Accumulations of animal feces encouraged dumping chamber pots into streets where night soil collection was impractical. [ 15 ] Combined sewers were built to use surface runoff to flush waste off streets and move it underground to places distant from populated areas. Sewage treatment became necessary as population expanded, but increased volumes and pumping capacity required for treatment of diluted waste from combined sewers is more expensive than treating undiluted sewage. [ 16 ]
Communities that have urbanized in the mid-20th century or later generally have built separate systems for sewage (sanitary sewers) and stormwater, because precipitation causes widely varying flows, reducing sewage treatment plant efficiency. [ 17 ]
In the UK, the term "foul sewer" was also in use for a sanitary sewer. | https://en.wikipedia.org/wiki/Sanitary_sewer |
Sanitary sewer overflow ( SSO ) is a condition in which untreated sewage is discharged from a sanitary sewer into the environment prior to reaching sewage treatment facilities. When caused by rainfall it is also known as wet weather overflow . Causes of sanitary sewer overflows include: Blockage of sewer lines, infiltration/Inflow of excessive stormwater into sewer lines during heavy rainfall , malfunction of pumping station lifts or electrical power failure , broken sewer lines. Prevention of such overflow events involves regular maintenance and timely upgrades of infrastructure.
SSOs can cause gastrointestinal illnesses ( waterborne diseases ), beach closures and restrictions on fish and shellfish consumption.
Developed countries such as the United States , Canada , most Western European nations (e.g. Italy and France ), Australia , Singapore , South Korea and Japan are struggling with public health problems of SSO prevention. The magnitude of the problem is much greater in most developing countries.
The U.S. Environmental Protection Agency (EPA) estimates that at least 23,000 to 75,000 SSO events occur in the United States each year. [ 1 ] EPA estimated that upgrading every municipal treatment and collection system to reduce the frequency of overflow events to no more than once every five years would cost about $88 billion as of 2004. [ 2 ] This cost would be in addition to approximately $10 billion already invested. Although the volume of untreated sewage discharged to the environment is less than 0.01 percent of all treated sewage in the United States, the total volume amounts to several billion gallons per annum and accounts for thousands of cases of gastrointestinal illness each year. [ 2 ] : Ch. 6
Developed European countries and Japan have similar or somewhat larger percentages of SSO events compared to the U.S. [ citation needed ]
In developing countries , most wastewater is still not treated when discharged into the environment. The People's Republic of China discharged about 55 percent of all sewage without treatment of any type, as of 2001. [ 3 ] In a relatively developed Middle Eastern country such as Iran , the majority of Tehran 's population has totally untreated sewage injected to the city's groundwater. [ 4 ] In Venezuela , a below-average country in South America with respect to wastewater treatment, 97 percent of the country's sewage is discharged untreated into the environment. [ 5 ]
In many countries there are obligations to measure and report SSO occurrence using real-time telemetry to warn the public, bathers and shellfishery operators. [ citation needed ]
Sewers that were built in the early stages of urbanization were usually built before sewage treatment was implemented. [ 6 ] Early sewers were simple drainage systems to remove surface runoff with any waste material it might contain. These drainage systems became combined sewers when sewage from kitchens, baths, and toilets was added; and the discharge became offensive. Early sewage treatment plants were built to treat the sewage during dry weather; but it was infeasible to treat the larger volume of mixed sewage and precipitation runoff from combined sewers during wet weather. Some cities built sanitary sewers to keep sewage from being mixed with surface runoff so the sewage could be efficiently treated during both wet and dry weather. [ 7 ] (About 860 communities in the U.S. continue to use combined sewers. [ 8 ] )
Decentralized failures in dry weather mainly occur from collection sewer line blockages, which can arise from a debris clog or tree root intrusion into the line itself. Approximately half of SSOs in the United States are caused by blockage. [ 2 ] : p. 4–26 Grease is the blocking agent in approximately half of U.S. SSOs attributed to blockage, and solid debris is the blocking agent for another 25 percent. Roots are a contributing factor in approximately one-quarter of United States SSOs attributed to blockage. Grease deposits are caused by cooking fats liquified with hot water for discharge to sanitary sewers. These fats congeal as solid deposits in the cooler sewer. Solid debris includes soiled clothing, diapers , and sanitary napkins flushed down the toilet rather than being put in a waste bin. [ 2 ] : p. 4–28
Many U.S. municipalities require restaurants and food processing businesses to use grease interceptors and regulate the disposal of fats, oil and grease in the sewer system. [ 9 ]
One of the main problems of a decentralized line failure is the difficulty of defining the location of overflow, since a typical urban system contains thousands of miles of collection pipes, and the central treatment plant has no way of communicating with all the lines, unless expensive monitoring equipment has been installed. Companies in the UK have widely deployed bulk dielectric transducers suspended in the sewers to detect high levels and to report the events back over fixed wireless data networks. In certain locations this practice has permitted the reduction of pollution events by up to 60 percent. [ citation needed ]
Dry weather blockage is less likely within combined sewers; because combined sewers designed for the additional volume of surface runoff are much larger than sanitary sewers. Combined sewer storm water regulators may be vulnerable to blockage by debris, but overflow from such blockage typically enters the diversion outfall to avoid flooding private or public property.
Approximately one-quarter of United States SSOs occur during heavy rainfall events, which can cause inflow of stormwater into sanitary sewers through damage, improper connections, or flooding buildings and lift stations in low-lying areas of the collection system. The combined flow of sewage and stormwater exceeds the capacity of the sanitary sewer system and sewage is released into homes, businesses and streets. [ 2 ] : p. 4–26 This circumstance is most prevalent in older cities whose subsurface infrastructure is quite old; Paris , London , Stockholm , [ 10 ] New York City , Washington, DC , and Oakland, California [ 11 ] are typical examples of such locations. Inflow into the sanitary lines can be caused by tree root rupture of subsurface lines or by mechanical fracture due to age and overpressure from trucks and buildings.
Another mode of system failure can include power outages , which may disable lift station pumps and cause sewage overflow from the lift station wet well. Lift station mechanical or power failure causes approximately ten percent of United States SSOs. This type of discharge is uncommon from combined sewers, because the combined volume of sewage and storm water discourages use of lift stations. Broken sewer lines are responsible for approximately ten percent of U.S. SSOs. [ 2 ] : p. 4–27
Power failure, human error , or mechanical failure may cause similar discharge of untreated or partially treated sewage from a sewage treatment plant; but this is typically regarded as a sewage treatment plant malfunction rather than a sanitary sewer overflow. Sewage treatment plants may be designed to capture overflow from malfunctioning units and discharge it to alternative treatment facilities. Flooding of private or public property is typically avoided by discharging the overflow to an outfall designed for discharge of treated sewage. [ 2 ] : p. ES–3
Human health impacts include significant numbers of gastrointestinal illness each year, although death from one overflow event is uncommon. Additional human impacts include beach closures, swimming restrictions and prohibition of the consumption of certain aquatic animals (particularly certain molluscs ) after overflow events. Ecological consequences include fish kills , harm to plankton and other aquatic microflora and microfauna. Turbidity increase and dissolved oxygen decrease in receiving waters can lead to accentuated effects beyond the obvious pathogenic induced damage to aquatic ecosystems . It is possible that higher life forms such as marine mammals can be affected since certain seals and sea lions are known to experience peaks in pathogenic harm. [ 12 ]
The concept of SSO containment valves has been pioneered in the UK and they are installed to mitigate dry spills, by correlating rainfall data with SSO spill activity. [ citation needed ]
Since medieval times rulers have been aware of the impact of raw sewage improperly discharged to the environment. Before treatment systems existed in 16th century England , King Henry VIII decreed that sewage troughs should be kept flowing so that they would not stagnate in London prior to reaching the River Thames ( London sewer system ). [ citation needed ]
In the 19th century, sewage treatment plants were first developed and installed in the U.S. and parts of Europe, and the concept of SSO was identified. SSOs were not recognized as a widespread environmental problem until the rise of environmental awareness in the 1960s. Around that time government agencies in the U.S. began identifying locations and frequencies of SSOs in a systematic way. Local governments heard complaints of citizens, and beach closure protocols were systematised to reduce risks to public health.
After passage of the Clean Water Act in 1972, the U.S. spent billions of dollars on upgrades to sewage treatment plants, with some associated repairs and improvements to the associated collection systems, where the overflows occur. EPA continues to provide funding for low-interest loans to communities for addressing SSO problems, through the Clean Water State Revolving Fund . [ 13 ]
In the 1990s Japan , the UK and a number of other European countries began earnest investigation of some of their countries’ overflow issues. [ citation needed ] | https://en.wikipedia.org/wiki/Sanitary_sewer_overflow |
A sanity check or sanity test is a basic test to quickly evaluate whether a claim or the result of a calculation can possibly be true. It is a simple check to see if the produced material is rational (that the material's creator was thinking rationally, applying sanity ). The point of a sanity test is to rule out certain classes of obviously false results, not to catch every possible error. A rule-of-thumb or back-of-the-envelope calculation may be checked to perform the test. The advantage of performing an initial sanity test is that of speedily evaluating basic function.
In arithmetic, for example, when multiplying by 9, using the divisibility rule for 9 to verify that the sum of digits of the result is divisible by 9 is a sanity test—it will not catch every multiplication error, but is a quick and simple method to discover many possible errors.
In computer science , a sanity test is a very brief run-through of the functionality of a computer program , system, calculation, or other analysis, to assure that part of the system or methodology works roughly as expected. This is often prior to a more exhaustive round of testing.
A sanity test can refer to various orders of magnitude and other simple rule-of-thumb devices applied to cross-check mathematical calculations . For example:
In software development, a sanity test (a form of software testing which offers "quick, broad, and shallow testing" [ 1 ] ) evaluates the result of a subset of application functionality to determine whether it is possible and reasonable to proceed with further testing of the entire application. [ 2 ] Sanity tests may sometimes be used interchangeably with smoke tests [ 3 ] insofar as both terms denote tests which determine whether it is possible and reasonable to continue testing further. On the other hand, a distinction is sometimes made that a smoke test is a non-exhaustive test that ascertains whether the most crucial functions of a programme work before proceeding with further testing whereas a sanity test refers to whether specific functionality such as a particular bug fix works as expected without testing the wider functionality of the software. [ citation needed ] In other words, a sanity test determines whether the intended result of a code change works correctly while a smoke test ensures that nothing else important was broken in the process. Sanity testing and smoke testing avoid wasting time and effort by quickly determining whether an application is too flawed to merit more rigorous QA testing , but needs more developer debugging .
Groups of sanity tests are often bundled together for automated unit testing of functions, libraries, or applications prior to merging development code into a testing or trunk version control branch , [ 4 ] for automated building , [ 5 ] or for continuous integration and continuous deployment . [ 6 ]
Another common usage of sanity test is to denote checks which are performed within programme code, usually on arguments to functions or returns therefrom, to see if the answers can be assumed to be correct. The more complicated the routine, the more important that its response be checked. The trivial case is checking to see whether the return value of a function indicated success or failure, and to therefore cease further processing upon failure. This return value is actually often itself the result of a sanity check. For example, if the function attempted to open, write to, and close a file, a sanity check may be used to ensure that it did not fail on any of these actions—which is a sanity check often ignored by programmers. [ 7 ]
These kinds of sanity checks may be used during development for debugging purposes and also to aid in troubleshooting software runtime errors . For example, in a bank account management application, a sanity check will fail if a withdrawal requests more money than the total account balance rather than allowing the account to go negative (which wouldn't be sane). Another sanity test might be that deposits or purchases correspond to patterns established by historical data—for example, large purchase transactions or ATM withdrawals in foreign locations never before visited by the cardholder may be flagged for confirmation. [ citation needed ]
Sanity checks are also performed upon installation of stable, production software code into a new computing environment to ensure that all dependencies are met, such as a compatible operating system and link libraries . When a computing environment has passed all the sanity checks, it's known as a sane environment for the installation programme to proceed with reasonable expectation of success.
A "Hello, World!" program is often used as a sanity test for a development environment similarly. Rather than a complicated script running a set of unit tests, if this simple programme fails to compile or execute, it proves that the supporting environment likely has a configuration problem that will prevent any code from compiling or executing. But if "Hello world" executes, then any problems experienced with other programmes likely can be attributed to errors in that application's code rather than the environment.
The Association for Computing Machinery , [ 8 ] and software projects such as Android , [ 9 ] MediaWiki [ 10 ] and Twitter , [ 11 ] discourage use of the phrase sanity check in favour of other terms such as confidence test , coherence check , or simply test , as part of a wider attempt to avoid ableist language and increase inclusivity . | https://en.wikipedia.org/wiki/Sanity_check |
University of Rajasthan
Sanjay Mathur (born 1968) is an inorganic chemist, current president (Oct. 2022 - Oct. 2023) of the American Ceramic Society . [ 1 ] acting director of the Institute of Inorganic Chemistry at the University of Cologne , [ 2 ] honorary co-director of the Institute of Renewable Energy Sources at the Xi'an Jiaotong University , [ 3 ] a World Class University Professor at the Chonbuk University . [ 3 ] He is an adjunct professor at the Indian Institutes of Technology [ 4 ] in Chennai and has held visiting professorships at the Central South University , [ 5 ] the Tokyo University of Agriculture and Technology , [ 5 ] the National Institute of Science Education and Research . [ 5 ] He was awarded the Honorary Doctorate of the Vilnius University in 2016. [ 4 ] He is an elected fellow of the American Ceramic Society , [ 6 ] the American Society for Metals , [ 7 ] the European Science Academy, [ 8 ] the Indian National Science Academy [ 9 ] and has been awarded with the fellowships of the Alexander von Humboldt Foundation . [ 10 ] Mathur is known for his library of single source precursors for the production of nanostructured ceramic materials with tailormade properties, [ 11 ] attaining a h-index of 70 and over 18000 citations. [ 12 ]
In 1994 he moved to Germany, joined the Saarland University as an Alexander von Humboldt Fellow [ 10 ] (1994-1996). Following this, he worked for his habilitation (2004) [ 13 ] at the Saarland University until he accepted an offer of the Würzburg University in 2006 to become a Professor of Inorganic Chemistry. At the Würzburg University he established a research programm on the synthesis of nanomaterials and thin film systems by means of chemical vapour deposition using chemically tailored organometallic precursors. [ 14 ] In 2008, he was offered a full professorship in Inorganic and Materials Chemistry at the University of Cologne which he accepted. [ 13 ] He established the Steinbeis technology-transfer center Materials Alliance Cologne, [ 15 ] which supports small- and medium-sized enterprises to innovate their technology portfolio.
Mathur serves as Board member for the German Ceramic Society [ 16 ] and the federation of chemical industries ChemCologne in Rhineland. [ 17 ] Mathur has mentored a number of doctoral and postdoctoral researchers from a large number of nations. He has also served as the “International Ambassador” of the University of Cologne to foster international collaboration. [ 3 ] He has received calls as the director of the Institute for Functional Materials in KTH Royal Institute of Technology (2013) [ 18 ] and director of Institute for Technologies of Ceramic Components and Composites at the Stuttgart University (2020). [ 19 ]
Mathur's research focuses on chemical concepts for the synthesis and processing of nanostructured ceramics and composites through the transformation of specially developed chemical feedstocks for energy and health applications. His research group has developed approaches for processing metal oxide nanoparticles , nanowires and nanostructured coatings , applicable in the fields of biomedicine (e.g. drug delivery and implant integration), sensing (gas and moisture detection), protective coatings (including barrier and anti-corrosion solutions) and functional surface modifications (e.g. transparent conductive oxides, photocatalytic materials and hydrophobic / hydrophilic coatings). [ 3 ] [ 13 ]
Mathur has also played a role in coordinating joint research projects with European consortia and industrial partners. He has been involved in technology transfer and collaboration with industry, particularly in the areas of sensors , electrodes , filters, catalytic supports and battery applications. [ 3 ] [ 13 ]
Mathur has published more than 500 articles including 15 reviews and book chapters. [ 12 ] [ 4 ] He has been invited to speak at over 200 international conferences, has given over 250 seminars in 35 countries and has chaired/co-chaired several international conferences and symposia. [ 4 ] He has edited 11 book in the field of nanomaterials science and engineering and is the co-owner of 11 patents originated in joint research projects and industrial collaboration. [ 4 ] Mathur has led joint research projects with industry and has been involved with technology transfer and industrial collaborations. He serves as the Faculty Advisor for the International Chapters of the Materials Research Society , jointly recognized by the European Materials Research Society (E-MRS) as well as the American Ceramic Society International Germany Chapter established at the University of Cologne . [ 20 ] | https://en.wikipedia.org/wiki/Sanjay_Mathur |
Sankofa (pronounced SAHN -koh-fah) is a word in the Twi language of Ghana meaning “to retrieve" (literally "go back and get"; san - to return; ko - to go; fa - to fetch, to seek and take) and also refers to the Bono Adinkra symbol represented either with a stylized heart shape or by a bird with its head turned backwards while its feet face forward carrying a precious egg in its mouth. Sankofa is often associated with the proverb, “ Se wo were fi na wosankofa a yenkyi ," which translates as: "It is not wrong to go back for that which you have forgotten." [ 1 ] [ 2 ]
The sankofa bird appears frequently in traditional Akan art , and has also been adopted as an important symbol in an African-American and African Diaspora context to represent the need to reflect on the past to build a successful future. It is one of the most widely dispersed adinkra symbols, appearing in modern jewelry, tattoos, and clothing.
The Akan people of Ghana use an adinkra symbol to represent the same concept. One version of it is similar to the eastern symbol of a heart, and another is that of a bird with its head turned backwards to symbolically capture an egg depicted above its back. It symbolizes taking from the past what is good and bringing it into the present in order to make positive progress through the benevolent use of knowledge. Adinkra symbols are used by the Akan people to express proverbs and other philosophical ideas.
The sankofa bird also appears on carved wooden Akan stools, [ 3 ] in Akan goldweights , on some ruler's state umbrella or parasol ( ntuatire ) finials and on the staff finials of some court linguists. [ 4 ] It functions to foster mutual respect and unity in tradition. [ 5 ]
During a building excavation in Lower Manhattan in 1991, a cemetery for free and enslaved Africans was discovered. Over 400 remains were identified, but one coffin in particular stood out. Nailed into its wooden lid were iron tacks, 51 of which formed an enigmatic, heart-shaped design that some have interpreted as a sankofa symbol. [ 6 ] [ 7 ] The site is now a national monument, known as the African Burial Ground National Monument , administered by the National Park Service . A copy of the design found on the coffin lid is prominently carved onto a large black granite memorial at the center of the site. [ 8 ]
The National Museum of African American History and Culture uses the heart-shaped symbol on its website. [ 9 ] The "mouse over" for the image reads: "The Sankofa represents the importance of learning from the past."
Sankofa symbols show themselves all over cities like Washington, D.C. , and New Orleans , particularly in fence designs.
Janet Jackson has a sankofa tattoo on her inner right wrist. The symbol is also featured in her 1997 album The Velvet Rope , as well as on the supporting tour.
Sankofa is an event used by Saint Louis University to honor African-American student graduates and students who graduate with degrees in African American studies.
The symbol and name were used in the 1993 film Sankofa by Haile Gerima , as well as in the graphic title of the film 500 Years Later by Owen 'Alik Shahadah.
A UK stage production by Adzido Pan-African Dance Ensemble, scripted by Margaret Busby and premiered in 1999, was entitled Sankofa . [ 10 ]
The African-American string band Sankofa Strings , founded in 2005 by Sule Greg C. Wilson, Rhiannon Giddens , and Dom Flemons , was featured in the 2007 jug band documentary Chasin' Gus' Ghost . The band self-released the CD Colored Aristocracy in 2006. A second iteration of the band Sankofa, with Wilson and Flemons, as well as Ndidi Onukwulu and Allison Russell, released the CD The Uptown Strut in 2012.
Cassandra Wilson recorded the song "Sankofa", which appeared on her 1993 album Blue Light 'til Dawn .
A Sankofa bird appears several times in the BBC Television show Taboo . It was carved into the floor of a slave ship by James Keziah Delaney and appears as a tattoo on his upper back and as a drawing within the fireplace of his mother’s old room.
The protagonist in Remote Control by Nnedi Okorafor goes by the name Sankofa. [ 11 ]
On 14 December 2023, a committee of the City of Toronto, Canada unanimously selected the name “Sankofa Square” for Yonge-Dundas Square, in the press release, to right wrongs, confront anti-Black racism and build a more inclusive Toronto. [ 12 ] This and other renamings will occur throughout 2024. | https://en.wikipedia.org/wiki/Sankofa |
In mathematics and information theory , Sanov's theorem gives a bound on the probability of observing an atypical sequence of samples from a given probability distribution . In the language of large deviations theory , Sanov's theorem identifies the rate function for large deviations of the empirical measure of a sequence of i.i.d. random variables.
Let A be a set of probability distributions over an alphabet X , and let q be an arbitrary distribution over X (where q may or may not be in A ). Suppose we draw n i.i.d. samples from q , represented by the vector x n = ( x 1 , x 2 , … , x n ) {\displaystyle x^{n}=(x_{1},x_{2},\ldots ,x_{n})} . Then, we have the following bound on the probability that the empirical measure p ^ x n {\displaystyle {\hat {p}}_{x^{n}}} of the samples falls within the set A :
where
In words, the probability of drawing an atypical distribution is bounded by a function of the KL divergence from the true distribution to the atypical one; in the case that we consider a set of possible atypical distributions, there is a dominant atypical distribution, given by the information projection.
Furthermore, if A is a closed set, then
Define:
{ ( a 1 / n , … , a | Σ | / n ) : ∑ i a i = n , a i ∈ N } {\displaystyle \{(a_{1}/n,\dots ,a_{|\Sigma |}/n):\sum _{i}a_{i}=n,a_{i}\in \mathbb {N} \}} Then, Sanov's theorem states: [ 1 ]
Here, i n t ( S ) {\displaystyle int(S)} means the interior , and c l ( S ) {\displaystyle cl(S)} means the closure .
This probability -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Sanov's_theorem |
SBA-15 , an acronym for Santa Barbara Amorphous-15 , is a silica-based ordered mesoporous material that was first synthesized by researchers at the university of California Santa Barbra in 1998. [ 1 ] This material proved important for scientists in various fields such as material sciences, [ 2 ] drug delivery, [ 3 ] catalysis, [ 4 ] fuel cells [ 5 ] and many other due to its desirable properties and ease of production.
The procedure is a typical Liquid-Crystal templating that consists of three steps:
The interest in SBA-15 comes from the fact that its mostly mesoporous – meaning the pores are in the range of 2 nm to 50 nm according to the IUPAC definition [ 8 ] and the fact that these pores have a well defined structure that is cylindrical shape in hexagonal ordering with their relatively thick pore walls which gives thermal stability. [ 9 ]
The sorption isotherms of these materials, demonstrate typical hysteric behavior, which is still under discussion for its causes. [ 2 ]
The transmission electron microscopy of the sample shows the cylindrical pores but also highlights the fact that the pores of this material exhibit geometric deformations.
The small-angle X-ray scattering pattern shows typical Bragg peaks to the hexagonal structure of the material. The peak positions, is directly related to the lattice parameter .
q h k = 4 π a 3 h 2 + k 2 + h k {\displaystyle q_{hk}={\frac {4\pi }{a{\sqrt {3}}}}{\sqrt {h^{2}+k^{2}+hk}}}
where h and k are the miller indices . | https://en.wikipedia.org/wiki/Santa_Barbara_Amorphous-15 |
The Santa Margherita Lines ( Maltese : Is-Swar ta' Santa Margerita ), also known as the Firenzuola Lines ( Maltese : Is-Swar ta' Firenzuola ), are a line of fortifications in Cospicua , Malta . They were built in the 17th and 18th centuries to protect the land front defences of the cities of Birgu and Senglea . A second line of fortifications, known as the Cottonera Lines , was later built around the Santa Margherita Lines, while the city of Cospicua was founded in the 18th century within the Santa Margherita and Cottonera Lines.
The Santa Margherita Lines have been on Malta's tentative list of UNESCO World Heritage Sites since 1998, as part of the Knights' Fortifications around the Harbours of Malta . [ 1 ]
The lines, also known as Santa Margherita Enceinte , were built to the designs of the Dominican Cardinal Fra Vincenzo Maculano da Firenzuola . [ 2 ] [ 3 ] [ 4 ]
The foundation stone of the Santa Margherita Lines was laid on 30 December 1638 by Grand Master Giovanni Paolo Lascaris . The lines were designed by Vincenzo Maculano da Firenzuola , and were meant to protect the land fronts of Birgu and Senglea , and also to prevent a flanking attack on the capital Valletta . [ 5 ] [ 6 ] The lines were built on Santa Margherita Hill, known colloquially as il-Mandra , [ 6 ] possibly on the ruins of an ancient Greek temple or an earlier castle. [ 5 ] The hill is featured in the account of the Great Siege of 1565 by arquebusier Francesco Balbi di Corregio, who mentioned that a belvedere existed on it.
The engineer of the Grand Duke of Tuscany , Marquis di S. Angelo, has proceeded for the construction project in the building of the lines. [ 6 ]
When the three central bastions were completed in 1645, construction work stopped due to a lack of funds. The lines remained unfinished for many years, and they became known as Fort Santa Margarita or Fort Margarita . [ 5 ] In the 1670s, the Cottonera Lines were built around the still unfinished Santa Margherita Lines, but construction of the new fortifications was suspended in 1680 with the death of Grand Master Cotoner. [ 7 ]
Construction of both the Santa Margherita and the Cottonera Lines resumed in 1715. At the time of completion in 1736, the Santa Margherita Lines consisted of five bastions, two demi-bastions, six curtain walls, three gateways, at least two sally ports, a ditch, a covertway with lunette, and a glacis. [ 8 ]
The British modified the lines in the 1850s with the construction of Fort Verdala and St. Clement's Retrenchment. The latter connected the Santa Margherita Lines with the Cottonera Lines. In the late 19th century, the western part of the lines was demolished to make way for an extension of the Malta Dockyard .
The fortifications were included on the Antiquities List of 1925. [ 9 ] Most of the lines still exist today, but they are in a dilapidated state. Modern roads breach some of the bastions and curtain walls.
The Santa Margherita Lines as completed in 1736 consisted of the following bastions and curtain walls (listed going clockwise along the lines):
The 19th century additions by the British were: | https://en.wikipedia.org/wiki/Santa_Margherita_Lines |
Santucci's armillary sphere is a Ptolemaic armillary sphere at the Museo Galileo in Florence , the largest existing in the world. [ 1 ]
Begun on March 4, 1588, and completed on May 6, 1593, this large armillary sphere was built under the supervision of Antonio Santucci at the request of Ferdinand I de' Medici . The sphere represents the "universal machine" of the world according to the concepts developed by Aristotle and perfected by Ptolemy . The terrestrial globe is placed at the center, and it also displays territories that were still relatively little known at the time: notably, it includes both Lake Albert and Lake Victoria in central Africa, which were apparently forgotten again until the explorations of Samuel Baker and John Hanning Speke over 250 years later. [ 2 ]
The device was restored in the 19th century but is now incomplete and some of its parts are mismatched. The wooden parts of the sphere are elaborately painted and covered with fine gold leaf . The sphere rests on a stand with four sirens.
This model is similar to a smaller one built by Santucci in 1582 for King Philip II of Spain , now in the Escorial Library . | https://en.wikipedia.org/wiki/Santucci's_Armillary_Sphere |
The sapheno-femoral junction (SFJ) is located at the saphenous opening within the groin and formed by the meeting of the great saphenous vein (GSV), common femoral vein and the superficial inguinal veins (confluens venosus subinguinalis). [ 1 ] [ 2 ] It is one of the distinctive points where a superficial vein meets a deep vein and at which incompetent valves may occur. [ 3 ]
The SFJ can be located in the groin crease, [ 4 ] or in a 3 × 3 cm region situated up to 4 cm to the side and up to 3cm below to the pubic tubercle . It is nearer to the pubic tubercle in younger and thinner subjects. [ 5 ]
The GSV has two valves near the SFJ. One is a terminal valve about 1-2mm from the opening into the femoral vein and the other is about 2cm away. [ 4 ]
This anatomy article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Saphenofemoral_junction |
A saponifiable lipid is part of the ester functional group. They are made up of long chain carboxylic (of fatty) acids connected to an alcoholic functional group through the ester linkage which can undergo a saponification reaction. The fatty acids are released upon base-catalyzed ester hydrolysis to form ionized salts. The primary saponifiable lipids are free fatty acids , neutral glycerolipids , glycerophospholipids , sphingolipids , and glycolipids . [ 1 ]
By comparison, the non-saponifiable class of lipids is made up of terpenes, including fat-soluble A and E vitamins, and certain steroids, such as cholesterol. [ 2 ]
Saponifiable lipids have relevant applications as a source of biofuel and can be extracted from various forms of biomass to produce biodiesel. [ 1 ] [ 3 ]
This biochemistry article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Saponifiable_lipid |
Saponification is a process of cleaving esters into carboxylate salts and alcohols by the action of aqueous alkali . Typically aqueous sodium hydroxide solutions are used. [ 1 ] [ 2 ] It is an important type of alkaline hydrolysis . When the carboxylate is long chain, its salt is called a soap . The saponification of ethyl acetate gives sodium acetate and ethanol:
Vegetable oils and animal fats are the traditional materials that are saponified. These greasy materials, triesters called triglycerides , are usually mixtures derived from diverse fatty acids. In the traditional saponification, the triglyceride is treated with lye , which cleaves the ester bonds, releasing fatty acid salts (soaps) and glycerol . In one simplified version, the saponification of stearin gives sodium stearate .
This process is the main industrial method for producing glycerol ( C 3 H 5 (OH) 3 ).
Some soap-makers leave the glycerol in the soap. Others precipitate the soap by salting it out with sodium chloride .
Fat in a corpse converts into adipocere , often called "grave wax". This process is more common where the amount of fatty tissue is high and the agents of decomposition are absent or only minutely present.
The saponification value is the amount of base required to saponify a fat sample. [ 3 ] Soap makers formulate their recipes with a small deficit of lye to account for the unknown deviation of saponification value between their oil batch and laboratory averages.
The hydroxide anion adds to the carbonyl group of the ester. The immediate product is called an orthoester .
Expulsion of the alkoxide generates a carboxylic acid:
The alkoxide ion is a strong base so the proton is transferred from the carboxylic acid to the alkoxide ion, creating an alcohol:
In a classic laboratory procedure, the triglyceride trimyristin is obtained by extracting it from nutmeg with diethyl ether . Saponification to the soap sodium myristate takes place using NaOH in water. Treating the soap with hydrochloric acid gives myristic acid . [ 4 ]
The reaction of fatty acids with base is the other main method of saponification. In this case, the reaction involves neutralization of the carboxylic acid . The neutralization method is used to produce industrial soaps such as those derived from magnesium, the transition metals, and aluminium. This method is ideal for producing soaps that are derived from a single fatty acid, which leads to soaps with predictable physical properties, as required by many engineering applications.
Depending on the nature of the alkali used in their production, soaps have distinct properties. Sodium hydroxide (NaOH) produces "hard" soaps ; hard soaps can also be used in water containing Mg, Cl, and Ca salts. [ 5 ] By contrast, potassium soaps (derived using KOH ) are "soft" soaps . The fatty acid source also affects the soap's melting point. Most early hard soaps were manufactured using animal fats and KOH extracted from wood ash ; these were broadly solid. However, the majority of modern soaps are manufactured from polyunsaturated triglycerides such as vegetable oils . As in the triglycerides they are formed from [ 6 ] the salts of these acids have weaker inter-molecular forces and thus lower melting points.
Lithium 12-hydroxystearate and other lithium -based fatty acids are important constituents of lubricating greases. In lithium-based greases , lithium carboxylates are thickeners. "Complex soaps" are also common, these being combinations of more than one acid salt, such as azelaic or acetic acid . [ 7 ]
Fires involving cooking fats and oils (classified as class K (US) or F (Australia/Europe/Asia) ) burn hotter than most flammable liquids, rendering a standard class B extinguisher ineffective. Such fires should be extinguished with a wet chemical extinguisher . Extinguishers of this type are designed to extinguish cooking fats and oils through saponification. The extinguishing agent rapidly converts the burning substance to a non-combustible soap.
Saponification can occur in oil paintings over time, causing visible damage and deformation. Oil paints are composed of pigment molecules suspended in an oil-binding medium . Heavy metal salts are often used as pigment molecules, such as in lead white , red lead , and zinc white . [ 8 ] If those heavy metal salts react with free fatty acids in the oil medium, metal soaps may form in a paint layer that can then migrate outward to the painting's surface. [ 9 ] : 12–19
Saponification in oil paintings was described as early as 1912. [ 10 ] : 151 It is believed to be widespread, having been observed in many works dating from the fifteenth through the twentieth centuries; works of different geographic origin; and works painted on various supports, such as canvas, paper, wood, and copper. Chemical analysis may reveal saponification occurring in a painting's deeper layers before any signs are visible on the surface, even in paintings centuries old. [ 9 ] : 16
The saponified regions may deform the painting's surface through the formation of visible lumps or protrusions that can scatter light. These soap lumps may be prominent only on certain regions of the painting rather than throughout. In John Singer Sargent 's famous Portrait of Madame X , for example, the lumps only appear on the blackest areas, which may be because of the artist's use of more medium in those areas to compensate for the tendency of black pigments to soak it up. [ 9 ] : 12–13, 15 The process can also form chalky white deposits on a painting's surface, a deformation often described as "blooming" or "efflorescence", and may also contribute to the increased transparency of certain paint layers within an oil painting over time. [ 9 ] : 16, 19
Saponification does not occur in all oil paintings and many details are unresolved. [ 9 ] : 19 At present, retouching is the only known restoration method. | https://en.wikipedia.org/wiki/Saponification |
Saponification value or saponification number ( SV or SN ) represents the number of milligrams of potassium hydroxide (KOH) or sodium hydroxide (NaOH) required to saponify one gram of fat under the conditions specified. [ 1 ] [ 2 ] [ 3 ] It is a measure of the average molecular weight (or chain length) of all the fatty acids present in the sample in form of triglycerides . The higher the saponification value, the lower the fatty acids average length, the lighter the mean molecular weight of triglycerides and vice versa. Practically, fats or oils with high saponification value (such as coconut and palm oil) are more suitable for soap making.
To determine saponification value, the sample is treated with an excess of alkali (usually an ethanolic solution of potassium hydroxide) for half an hour under reflux . The KOH is consumed by reaction with triglycerides, which consume three equivalents of base. Diglycerides consume two equivalents of KOH. Monoglycerides and free fatty acids, as well as other esters such as lactones , consume one equivalent of base. [ 4 ] : 98 At the end of the reaction the quantity of KOH is determined by titration using standard solution of hydrochloric acid (HCl). Key to the method is the use of phenolphthalein indicator, which indicates the consumption of strong base (KOH) by the acid, not the weak base (potassium carboxylates). The SV (mg KOH/ g of sample) is calculated as following: [ 2 ]
Eq. 1
For example, standard methods for determination of SV of vegetable and animal fats are as follows:
The SV can also be calculated from the fatty acid composition as determined by gas chromatography ( AOCS Cd 3a-94). [ 5 ]
Handmade soap makers who aim for bar soap use sodium hydroxide (NaOH), commonly known as lye , rather than KOH (caustic potash) which produces soft paste, gel or liquid soaps. In order to calculate the lye amount needed to make bar soap, KOH values of SV can be converted to NaOH values by dividing KOH values by the ratio of the molecular weights of KOH and NaOH (1.403). [ 6 ]
The theoretical SV of a pure triglyceride molecule can be calculated by the following equation (where MW is its molecular weight): [ 7 ] [ 8 ]
Eq. 2
For instance, triolein , a triglyceride occurring in many fats and oils, has three oleic acid residues esterified to a molecule of glycerol with a total MW of 885.4 (g / mol). Therefore, its SV equals 190 mg KOH / g sample. [ 9 ] In comparison, trilaurin with three shorter fatty acid residues ( lauric acid ) has a MW of 639 and an SV of 263.
As it can be seen from equation (2) , the SV of a given fat is inversely proportional to its molecular weight. Actually, as fats and oils contain a mix of different triglycerides species, the average MW can be calculated according to the following relation: [ 9 ]
Eq. 3
This means that coconut oil with an abundance of medium chain fatty acids (mainly lauric acid) contain more fatty acids per unit of weight than, for example, olive oil (mainly oleic acid). Consequently, more ester saponifiable functions were present per g of coconut oil, which means more KOH is required to saponify the same amount of matter, and thus a higher SV. [ 9 ] The calculated molecular weight (Eq. 3 ) is not applicable to fats and oils containing high amounts of unsaponifiable material, free fatty acids (> 0.1%), or mono- and diacylglycerols (> 0.1%). [ 7 ]
Unsaponifiables are components of a fatty substance ( oil , fat , wax ) that fail to form soaps when treated with alkali and remain insoluble in water but soluble in organic solvents. For instance, typical soybean oil contains, by weight, 1.5 – 2.5% of unsaponifiable matter. Unsaponifiables include nonvolatile components : alkanes , sterols , triterpenes , fatty alcohols , tocopherols and carotenoids as well as those that mainly result from the saponification of fatty esters (sterols esters, wax esters, tocopherols esters, ...). This fraction may also contain environmental contaminants and residues of plasticizers , pesticides , mineral oil hydrocarbons and aromatics. [ 10 ]
Unsaponifiable constituents are an important consideration when selecting oil mixtures for the manufacture of soaps. Unsaponifiables can be beneficial to a soap formula because they may have properties such as moisturization , conditioning , antioxidant , texturing etc. On the other hand, when proportion of unsaponifiables is too high (> 3%), or the specific unsaponifiables present do not provide significant benefits, a defective or inferior soap product can result. For example, shark oil is not suitable for soap making as it may contain more than 10% of unsaponifiable matter. [ 11 ]
For edible oils, the tolerated limit of unsaponifiable matter is 1.5% (olive, refined soybean), while inferior quality crude or pomace oil could reach 3%. [ 12 ] [ 13 ]
Determination of unsaponifiables involves a saponification step of the sample followed by extraction of the unsaponifiable using an organic solvent (i.e. diethyl ether ). Official methods for animal and vegetable fats and oils are described by ASTM D1065 - 18, ISO 3596: 2000 or 18609: 2000, AOCS method Ca 6a-40. | https://en.wikipedia.org/wiki/Saponification_value |
A sapper , also called a combat engineer , is a combatant or soldier who performs a variety of military engineering duties, [ 1 ] such as breaching fortifications , demolitions , bridge -building, laying or clearing minefields , preparing field defenses, and road and airfield construction and repair.
Sappers are also trained and equipped to serve secondarily as provisional infantry. [ 2 ]
Sappers facilitate and support the movement, defense, and survival of superordinate and allied forces, and impede those of enemies.
The term "sapper" is used in the British Army and Commonwealth nations, the U.S. military, and the militaries of other countries.
A sapper, in the sense first used by the French military, was one who dug trenches to allow besieging forces to advance towards the enemy defensive works and forts over ground that is under the defenders' musket or artillery fire. It comes from the French word sapeur , [ 3 ] itself being derived from the verb saper (to undermine, to dig under a wall or building to cause its collapse). This digging was referred to as sapping the enemy fortifications. Saps were excavated by brigades of trained sappers or instructed troops. When an army was defending a fortress with cannons, they had an obvious height and therefore range advantage over the attacker's guns. The attacking army's artillery had to be brought forward, under fire, so as to facilitate effective counter-battery fire .
This was achieved by digging what the French termed a sappe [ 4 ] (derived from the archaic French word for spade or entrenching tool ). [ 5 ] [ 6 ] Using techniques developed and perfected by Vauban , the sappers began the trench at such an angle so as to avoid enemy fire enfilading the sappe by firing down its length. As they pressed forward, a position was prepared from which a cannon could suppress the defenders on the fort's bastions. The sappers would then change the course of their trench, zig-zagging toward the fortress wall. Each leg brought the attacker's artillery closer until the besieged cannon would be sufficiently suppressed for the attackers to breach the walls. Broadly speaking, sappers were originally experts at demolishing or otherwise overcoming or bypassing fortification systems.
An additional term applied to sappers of the British Indian Army was "miner." The native engineer corps were called "sappers and miners," for example, the Royal Bombay Sappers and Miners . The term arose from a task done by sappers to further the battle after saps were dug. The saps permitted cannons to be brought into firing range of the besieged fort and its cannons, but often the cannons themselves were unable to breach the fort walls. The engineers would dig a tunnel from the forward-most sap up to and under the fort wall, then place a charge of gunpowder and ignite it, causing an explosion that would destroy the wall and permit attacking infantry to close with the enemy. This was dangerous work, often lethal to the sappers, and was fiercely resisted by the besieged enemy. Since the two tasks went hand in hand and were done by the same troops, native Indian engineer corps came to be called "sappers and miners".
Sapper (abbreviated Spr) is the Royal Engineers ' equivalent of private . This is also the case within the Indian Army Corps of Engineers , Pakistan Army Corps of Engineers , Royal Canadian Engineers , Royal Australian Engineers , [ 7 ] South African Army Engineer Formation , Jamaica Defence Force Engineer Regiment, and Royal New Zealand Engineers . The term "sapper" was introduced in 1856, when the Corps of Royal Sappers and Miners was amalgamated with the officer corps of the Royal Engineers to form the Corps of Royal Engineers.
During the course of the First World War, some Royal Marines also took the rank of Sapper. This was adopted as tradition in the Royal Marine Divisional Engineers of the Royal Naval Division . [ 8 ]
During the Sinai and Palestine Campaign of World War I, Australian sappers repaired a bridge at the historic crossing of the Jordan River at Jisr Benat Yakub (also known as Jacob's Ford ). Here the retreating Ottoman and German rearguard had blown up the bridge's central arch, which was repaired in five hours by sappers attached to the Australian Mounted Division . While the light horse brigades forded the river, continuing the Desert Mounted Corps ' advance to Damascus , the sappers worked through the night of 27/28 September 1918, to repair the bridge to enable the division's wheeled vehicles and guns to follow on 28 September. [ 9 ] [ 10 ] [ 11 ]
In the Canadian Forces, sappers exist both in the regular force and reserve force. The rank of sapper is used instead of private trained to signify completion of the basic Engineer training course. Canadian sappers have been deployed in many major conflicts in recent history including World War I, World War II, the Korean War , and the War in Afghanistan . The roles of a sapper entail: Bridging with the ACROW or Medium Girder Bridge as well as non-standard bridge construction; obstacle and defensive construction; enemy obstacle reduction and clearance, mine warfare; explosive ordnance disposal; water supply using the reverse-osmosis water purification unit; building and maintaining roadways and airfields; combat diving; tactical breaching; and camp construction. Ultimately, the objective of the sappers is to facilitate the living, moving, and to fight for friendly troops on the battlefield and denying the same to enemy forces. The motto of the Canadian Military Engineers is Ubique ( Latin : everywhere ) a motto shared with the Royal Canadian Artillery .
The term "sappers", in addition to the connotation of rank of engineer private, is used collectively to informally refer to the Engineer Corps as a whole and also forms part of the informal names of the three combat engineer groups, viz. Madras Sappers , Bengal Sappers and the Bombay Sappers . Each of these groups consist of about twenty battalion-sized engineer regiments and additional company-sized minor engineer units. The three sapper groups are descended from the sapper and miner groups of the East India Company and later the British Indian Army of the British Raj .
In the Israel Defense Forces a sapper (in Hebrew : פלס, palas ) is the military profession of a combat soldier who went through basic combat engineering training. Most of the sappers are soldiers of the Combat Engineering Corps , but there are also infantry sappers, who are part of the infantry brigades and are organized in engineering companies called פלחה"ן ( palchan ). These companies are integral part of the infantry brigades. Combat engineering corps sappers are arranged in battalions.
Each sapper goes through high level infantry training, which qualifies him as rifleman 06 (רובאי 06). Combat engineering sappers are qualified as "sapper 06" (פלס 06). They are skilled in infantry combat, basic sabotage , landmine planting and demining , use of explosives , breaching and opening routes, trench warfare , and operating the IDF Puma combat engineering vehicle . Combat engineering commanders are qualified as "sapper 08" while combat engineering officers are qualified as "sapper 11". Both go through additional advance training to gain the skills needed for high level sapper profession.
The Israel Police also maintains a bomb disposal specialist unit. All police sappers must graduate from a 10-month training program at the bomb disposal training center in Beit Shemesh , which includes operational exercises, theoretical studies, and fieldwork. [ 12 ]
In Japan, Kōhei-ka ( 工兵科 [ ja ] , 工 means "engineer" and 兵 means "soldiers"), or Engineer Branch in English, was a branch (兵科) of the Imperial Japanese Army . General Yūsaku Uehara , who introduced the French sapeur or ingénieur system to IJA and authored the Kōhei Sōten (工兵操典, "Engineers' Manual"), is known as the "father of Japanese Kōhei " ("日本工兵の父").
Engineer Branch officers were considered technology specialists along with Artillery Branch (砲兵科) officers in IJA, except Technical Branch (技術科) officers who have an academic degree in science or engineering and developed military technology.
Selected Engineer and Artillery officers were educated at the Army Artillery and Engineering School ( 陸軍砲工学校 [ ja ] ). Artillery and Engineering School's Kōtō-ka (高等科, "Higher Course") was equivalent to the Army War College . Some Kōtōka graduates, like Lt. Gen. Takeo Yasuda , continued their studies as Rikugun Ingai Gakusei (陸軍員外学生) at Imperial University of Tokyo's Engineering Faculty and Science Faculty and obtained degrees. Due to the apparent importance of science and technology, Artillery and Engineering School was renamed Army Science School during World War II and was also studied by non-artillery and non-engineer officers.
Ordinary personnel at Engineer Branch are educated at the Army Engineer School ( 陸軍工兵学校 [ ja ] ) and other schools.
JGSDF Shisetsu-ka ( 施設科 [ ja ] , "施設" literally means "facilities"), or Engineer Branch in English, is equivalent to the IJA Kōhei-ka . In accordance with the JSDF's nomenclature, this title was devised to avoid the character for 'soldier', which evokes the military.
JGSDF Engineer Branch personnel are educated at JGSDF Engineer School ( 陸上自衛隊施設学校 [ ja ] ).
In France, sapper ( sapeur ) is the title of military combat engineers and firefighters , both civil and military, (sapper-fireman or sapeur-pompier ). Military sappers fall under the umbrella of the Engineering Arm or Arme du Génie . A related title is pioneer ( pionnier ), used only in the Foreign Legion .
The French Corps of Engineers was created under the command of Marshal Vauban during the late 17th century. Its members were called sappers if their function was to destroy enemy fortifications by using trenches or sape and miners if they engaged in tunnel warfare or mine . The Corps of the Engineers was suppressed during two short periods (1720-1729 and 1769–1793) and sappers and miners were part of the Artillery regiments. In 1793, the Corps was reorganized into companies of miners and battalions of sappers, each assigned to a particular division.
Eventually, as the missions of the Corps grew more diversified, additional titles were used by combat engineers, such as Conductor ( sapeur-conducteur ) in 1810, entrusted with the logistics of the Corps, Firefighter ( sapeur-pompier ) in 1810 or telegraph sapper ( sapeur-télégraphiste ). In 1814, the companies of miners were integrated into the sapper battalions, themselves organized in Engineers Regiments ( régiments du génie ). In 1875, the distinction between miners and sappers was abolished and all members of the Corps of Engineers were titled sappers-miners, though only sapper was used in common usage. In 1894, the pontonniers or bridgemakers were transferred from the Artillery Corps to the Engineers, thus creating the title sapeurs-pontonniers . In 1909, the Engineering Arm of the Army Staff was entrusted the burgeoning Air Service ( Aérostation militaire ), its personal was titled sapper-airman ( sapeur-aérostier ). The titled was disused in 1914 when the Air Service took its independence from the Engineering Arm.
The first fire company created by Napoléon I was a military sapper company of the French Imperial Guard , created in 1810. This company was tasked with the protection of the Imperial palaces after the tragic fire of the Austrian embassy in Paris on 1 July 1810. The Paris Fire Service ( gardes-pompes ), a civilian institution, was re-organized as a military unit in September 1811, becoming the Paris Sappers-Firefighters Battalion. Other cities kept or created civilian firefighters services but used the military ranks and organization of the Paris Battalion. In 1831, National Guard engineers companies became the reserve components of the Fire Services and kept their military organization even after the disappearance of the National Guard in 1852. Sapper-firefighter is the common title of the civilian and Paris firefighters in France, but the other military firefighters units, such as the Marseille Naval Fire Battalion , do not use the sapper title, as they had no military engineers lineage.
Since the 18th century, every grenadier battalion in the French Army had a small unit of pioneers , sometimes called sappers-pioneers ( sapeurs-pionniers ). They had the mission to advance under enemy fire in order to destroy the obstacles drawn by the enemy and to clear the way for the rest of the infantry . The danger of such missions resulted in pioneers having short life expectancies. Because of this, the army allowed them certain privileges such as the authorization to wear beards . In addition to their beards and axes, they traditionally wear leather aprons and gloves.
The pioneers units disappeared during the mid-20th c. century, their last appearance being the short-lived Pioneers Regiments of 1939–1944, a military public works service using the older draftees in the army. Only the Foreign Legion kept using a pioneer unit, mainly for representation duty. The current pioneer unit of the Legion reintroduced the symbols of the Napoleonic pioneers: the beard, the axe, the leather apron, the crossed-axes insignia, and the leather gloves. If the parades of the Legion are opened by this unit, it is to commemorate the traditional role of the pioneers "opening the way" for the troops. The pioneer unit is made up for parades of selected men taken in both the Infantry and the Engineers regiments of the Legion.
In the Hellenic Army , there is the "mechanic" or "Corps of Engineers" (μηχανικό; michaniko ). [ clarification needed ]
The Italian Army uses the term "Guastatori" for its combat engineers, "Pionieri" for its construction engineers, "Pontieri" for its bridging engineers, and "Ferrovieri" for its railroad engineers.
In Portugal, the term "sapper" is used both in the military and in the civilian environment. In the Portuguese Army , a sapador de engenharia (engineering sapper) is a soldier of the engineer branch that has specialized combat engineer training. A sapador de infantaria (infantry sapper) is a soldier of the infantry branch that has a similar training and who usually serves in the combat support sapper platoon of an infantry battalion. A sapador NBQ (NBC sapper) is an engineer branch soldier specialized in nuclear, biological and chemical warfare .
The bombeiros-sapadores ("sapper-firefighters") are the civil municipal professional firefighters that exist in the main cities of the country. The largest unit of this type is the Regimento de Bombeiros Sapadores ("sapper-firefighters regiment") maintained by the Lisbon municipal council. The sapadores florestais (forest sappers) are the professionals maintained by the government , local authorities and large private forestry companies, who cleans and maintain forests and prevents and fights forest fires .
In the Pakistan Army , sapper officers perform combat and normal engineer duties. The Corps is led by the Engineer-in-Chief who is a Lt Gen . The current Engineer-in-Chief is Lt Gen Khalid Asghar. The Frontier Works Organization , Military Engineering Service and the Survey of Pakistan is part of the corps. Initially part of the Indian Corps of Engineers , it dates back to 1780 but came to its modern form in 1947 following the Independence of Pakistan . Since then it has taken part in all wars including 1965 War , 1971 War and Kargil War . It has completed the Pakistan portion of Karakoram Highway . The corps is taking part in Operation Zarb-e-Azb
In the United States Army , sappers are combat engineers who support the front-line infantry , and they have fought in every war in U.S. history. For example, after the Battle of Yorktown , General Washington cited Louis Lebègue Duportail , the chief of engineers, for conduct that afforded "brilliant proofs of his military genius."
Designation as a "sapper" is also earned as an additional proficiency. The U.S. Army authorizes four skill tabs [ 13 ] for permanent wear above the unit patch on the left shoulder (Army Regulation 670-1 Chapter 29–13, Sub-Paragraph f). Along with the Sapper Tab , the Special Forces Tab , Ranger Tab , and President's Hundred Tab identify soldiers who have passed a demanding course of military instruction and have demonstrated their competence in particular specialties and skills.
To wear the Sapper Tab, a soldier must graduate from the Sapper Leader Course , which is operated by the U.S. Army Engineer School at Fort Leonard Wood , Missouri . The Sapper Leader Course is a demanding 28-day leadership development course for combat engineers that reinforces critical skills and teaches advanced techniques needed across the army. It is also designed to build esprit de corps by training soldiers in troop-leading procedures, demolitions (conventional and expedient), and mountaineering operations. The course culminates in an intense field-training exercise that reinforces the use of the battle drills and specialized engineer techniques learned throughout the course. The course is open to enlisted soldiers in the grades of E-4 (P) (Army specialists and corporals on the list for promotion to sergeant) through E-7, cadets, and officers O-3 (Captain) and below. The course is primarily for U.S. Army and USMC combat engineers, but may be attended by all service members with an approved waiver. [ 14 ]
PAVN (People's Army of Vietnam) and Viet Cong sappers, as they were called by US forces, are better described as commando units. The Vietnamese term đặc công can be literally translated as "special task". Thousands of specially trained elite fighters served in the PAVN and Viet Cong commando–sapper units which were organized as independent formations. While not always successful due to lack of appropriate personal weapon types for combat and assault like other special forces , they were still capable of inflicting heavy damage with their non-firearms arsenal. During the Vietnam War, they were armed with various types of bombs, mines, explosive charges, grenades and even steel-pellet mines which proved especially devastating. These are still the main weapons of the đặc công .
These elite units served as raiders against American/ ARVN troops, and infiltrated spearheads during the final Ho Chi Minh Campaign in 1975, where they seized key road and bridge assets, destroyed installations, attacked command and control nodes located deep inside enemy territory, planted explosives on U.S. water craft, and otherwise helped the PAVN's rapid mobile forces advance. A typical PAVN/VC đặc công organization is shown in the diagram. The raiding force was usually grouped into assault teams, each broken down into several 3–5-man assault cells. Overall, there were generally four operational echelons . [ 15 ]
An instance of a successful sapper attack conducted by the Viet Cong was the during the Battle of Fire Base Mary Ann . A small number of sappers, through surprise and deft coordination, conducted a successful attack on a superior US force. The battle was described as a "rampage of VC who threw satchels at the command bunker, knifed Americans in their sleep and destroyed all communications equipment. [ 16 ]
The Ottoman Empire had an infantry corp named Lağımcılar Ocağı (literally: Sapper Corps ). These infantries were used in most of the Empire's sieges, demolishing enemy fortifications and defences.
Sapper Island, St. Joseph Channel, Algoma District, Ontario was named in honour of sappers, especially those who graduated from the Royal Military College of Canada . [ 17 ] 46°18′56″N 83°57′29″W / 46.31556°N 83.95806°W / 46.31556; -83.95806 .
In Warsaw ( Poland ) there is memorial honouring sappers ( Pomnik Chwała Saperom )
In the 1978 song by Australian rock band Cold Chisel , " Khe Sanh ", the narrator (a fictional Australian army Vietnam War veteran) says "I left my heart to the sappers round Khe Sanh". However, the only sappers or combat engineers present at the historical Battle of Khe Sanh belonged to US, South Vietnamese and (opposing) North Vietnamese units.
In the 2008 science-fiction novel The Last Colony , a fictitious "sapper field" technology is used to disrupt enemy weapons operation.
Rudyard Kipling's poem "Sappers" (1896) [ 18 ] detailed some of the duties of Sappers in the British Army of Victorian times. The notes on this poem [ 19 ] further explain the duties referenced. | https://en.wikipedia.org/wiki/Sapper |
A Sapper Army ( Russian : сапёрная армия ) was a multi- brigade military construction engineer formation of the Engineer Troops (Soviet Union) of the Soviet Red Army during World War II . Formed to construct large-scale defensive works, sapper armies were used from late 1941 until mid-1942 when the Red Army opted to organize smaller and more flexible construction engineer formations. Although the organization of military construction engineers into an army -level echelon was unusual, the use of dedicated troops for military construction was common to many armies of World War II. [ 1 ]
Reeling from the German invasion of 1941, the Soviets decided to organize large military construction engineer formations to construct defensive works on a massive scale. The Soviets hoped such works would strengthen Red Army defensive operations and buy enough time to rebuild their forces for a counter-offensive.
Consequently, the high command ordered the formation of the first sapper armies on October 13, 1941. [ 2 ] Originally, six sapper armies were formed, but by December 1941 this was expanded to ten sapper armies, numbered First through Tenth. The sapper armies were not only composed of military personnel; "women, old men, schoolchildren and teenagers under the draft age" [ 3 ] were also mobilized to serve in the construction units.
The sapper armies worked to construct defensive lines that were made up of battalion and company strong points in the Moscow , Stalingrad, North Caucasus, and Volga military districts. Sapper armies also trained troops for the Red Army's engineers and consequently suffered a steady loss of qualified personnel.
Dissatisfied with the relative lack of flexibility of the sapper armies, the high command disbanded five of them in February 1942 and used the released personnel for the formation of new rifle ( infantry ) units. Confronted with the German summer offensive of 1942, the remaining sapper armies built defensive works around Moscow and Stalingrad, and in the Caucasus. On July 26, 1942, the high command directed the reorganization of the sapper armies, and by October 1942, the remaining five sapper armies had been converted into defensive construction directorates. The troops released by this measure were used to form new rifle and smaller engineer units.
Historian David Glantz assessed the effectiveness of the sapper armies as having "... contributed significantly to the Red Army's victories at Leningrad, Moscow, and Stalingrad by preparing defensive lines, providing vital engineering support to the Red Army's operating fronts, and serving as a base for the formation of other more specialized engineer forces assigned to operating fronts." [ 4 ]
Sapper armies were made up of two to four sapper brigades. A sapper brigade controlled 19 sapper battalions, each with three companies of four platoons. Sapper battalions had an authorized strength of 497 men, and included woodcutting units, road- and bridge-building units, units dedicated to the construction of defensive positions, and motorized tractor units. Fully manned, each sapper army was authorized some 45,000 to 50,000 men. [ 3 ] | https://en.wikipedia.org/wiki/Sapper_army |
Sapping is a term used in siege operations to describe the digging of a covered trench (a "sap" [ 1 ] ) to approach a besieged place without danger from the enemy's fire. [ 2 ] The purpose of the sap is usually to advance a besieging army's position towards an attacked fortification. It is excavated by specialised military units, whose members are often called sappers .
By using the sap, the besiegers could move closer to the walls of a fortress, without exposing the sappers to direct fire from the defending force. To protect the sappers, trenches were usually dug at an angle in zig-zag pattern (to protect against enfilading fire from the defenders), and at the head of the sap a defensive shield made of gabions (or a mantlet ) could be deployed.
Once the saps were close enough, siege engines or cannon could be moved through the trenches to get closer to—and enable firing at—the fortification. The goal of firing is to batter a breach in the curtain walls , to allow attacking infantry to get past the walls. Prior to the invention of large pieces of siege artillery , miners could start to tunnel from the head of a sap to undermine the walls. A fire or gunpowder would then be used to create a crater into which a section of the fortifications would fall, creating a breach.
Before the development of explosives, sapping was the undermining of an enemy's fortifications, which would collapse when the sap's supports were removed. [ 2 ] Later, explosives were placed surreptitiously in the undermining sap or mine, then detonated, as was done with 450 tons of high explosive in the First World War battle of Messines , the largest planned explosion until the 1945 Trinity atomic bomb test .
A way to force entry into a fortified structure was to dig a mine or sap under defensive walls, typically shored up by wooden props. On collapsing the tunnel, for example by burning the props, the wall would collapse. [ 3 ]
Sapping trenches, cannons and gunpowder explosives were a potent force against fortifications. However, the Siege of Godesberg of 1583 during the Cologne War showed that fortresses could still withstand sapping and explosives to a point. After the attacking force of Ferdinand of Bavaria fired on the fortress with large caliber cannons; this had little impact on the walls. The cannons were firing heavy shot, but the height of the fortress significantly reduced the force of the impact with the walls, which bounced off to little effect, although the fortress dated from the 14th century. To breach the walls, Ferdinand ordered his soldiers to dig into the feldspar supporting the side of the mountain and place an explosive charge. Even after the powder was ignited and a substantial portion of the wall, the gate, and the inner walls were breached, the defenders still held out for three days. [ 4 ]
Sapping became necessary as a response to the development and spread of trace Italienne in defensive architecture in the 1500s. The Italian style star fort bastion made siege warfare and sapping the modus operandi of military operations in the late medieval and first decades of the early modern period of warfare. [ 5 ] Fortresses with abutments with gentler angles were difficult to breach; cannonballs and mortar shells often had little impact on the walls, or impact that could be readily repaired after night fell. Towers no longer protruded at right angles from the wall; rather, they blended with the wall. These created a two-fold advantage. First, defenders in the towers had a field of fire of 280 degrees or more. This range of fire and the towers' positioning allowed defenders to fire upon the attackers' flank as they advanced, a deadly fire called enfilade . Consequently, a hostile force which ranged their cannons was less effective, as the "hostile cannon [had] to fire from longer range" and defenders could better enfilade attackers. [ 6 ]
During the English Civil War, there was a siege of Newark-on-Trent which took place from 6 March 1645 – 8 May 1646. A detailed map of the Cavaliers defences of Newark and the lines of circumvallation and contravallation along with the besiegers redoubts and fortified camps was drawn up by R Clampe, the besieging Roundheads ' chief engineer. It includes a zig-zag sap emerging from a bastion of the circumvallation. The zig-zags are at such angles and positions that the defenders were unable to bring enfilade fire to bear. Once the sap was completed four cannons were placed much closer to a gateway than those in bastions of the circumvallation.
In the American Civil War , troops advanced their sap under cover of a sap roller [ 7 ] or mantlet [ 8 ] by forming a parapet on the engaged side of the trench one gabion at a time and filling it with earth taken from the trench.
During First World War trench warfare, the combatant's sappers, who were often experienced civilian miners who had been rejected for combat duties due to age or ill-health, strived to undermine each other's positions, working silently to avoid detection. After completing a mine it was filled with explosives, sometimes hundreds of tons, and detonated, followed by an attack on the surprised survivors from the destroyed position. [ 9 ]
A Russian sap is a tunnel dug at a shallow depth under no man's land towards an enemy position. It allows the attacking infantry to approach an enemy position without being detected and safe from enemy fire. For the attack, the tunnel is opened and the infantry attacks the enemy position at comparatively short range. Russian saps were widely used in the First World War , for example during the Battle of the Somme , when four of them were further equipped with Livens Large Gallery Flame Projectors . Similar tactics were used in the Korean War by the Chinese People's Volunteer Army , when they dug under the Yalu River to attack US troops, and by Hamas , when carrying out tunnel warfare from the Gaza Strip against Israel . | https://en.wikipedia.org/wiki/Sapping |
The saprobic system is a tool to measure water quality, and specifically it deals with the capacity of a water body to self-regulate and degrade organic matter. The saprobic system derives from so-called saprobes — organisms that thrive through degradation of organic matter, which is called saprotrophic nutrition .
The saprobic system is based on a survey of indicator organisms. For example, the abundance of Lymnaea stagnalis water snails and other organisms is estimated, and using a formula, the listed saprobic and tolerance values of the organisms allow the water quality grade — the saprobic index — to be computed.
Saprobic water quality is expressed in four classes ranging from I to IV; and with three intermediate grades (I-II, II-III and III-IV). Water bodies of class I are the cleanest and of the highest quality. The inherent drawback of the saprobic systems as a water quality measure is that it only regards biodegradable organic material, and so ignores other factors like heavy metal pollution. Though the presence of certain organisms can rule out the presence of toxic substances, the incorporation of such organisms would deviate from the saprobic system's concept.
This section explains how the saprobic index of a water body is computed according to the Zelinka & Marvan method; without adjusting for several confounding factors. [ 1 ]
In a first iteration, the abundance A of each indicator species is counted and converted to categories ranging from 1 to 7. An abundance of 1 means that only one or two animals were found, while the class 7 means more than 1000 individuals during a survey. There are different abundance classes — for example, some methods use classes where the next-bigger class contains roughly double the number of individuals. The following table follows the DIN 38410-1 (2008) standard used in Germany, where the next-bigger class is about three times larger than the previous one.
The saprobic value s denotes how much organic matter must be present for an aquatic species to thrive. An animal with a saprobic value 1 can only survive in water with little organic matter present, while one with a value of 4 requires water bodies with a large amount of organic matter. The aforementioned example, the Lymnaea stagnalis snail, has a saprobic value of 2.0. The annelid worm Tubifex tubifex needs a lot of organic matter and has an s value of 3.6.
The weighting factor g has a value of either 1, 2, 4, 8 or 16, and denotes a tolerance range. If a species can survive in both unpolluted and heavily polluted water, g is very small because finding the species in a survey has little predictive value. In practice, only indicator species with a weighting factor g ≥ 4 are used. For example, a caddisfly , Agapetus fuscipes , has a g value of 16, while the zebra mussel 's value is g = 4.
The saprobic index of a water body - the water quality - is finally computed with the following formula:
The water body's quality, in Roman numerals, is the rounded value of S .
Source [ 2 ]
The species used in Germany to measure saprobic water quality tend to group around s = 2, while other countries like Austria and the Czech Republic use a more diverse list of organisms. [ 4 ]
The earlier Pantle & Buck method (1955) uses the same saprobic values s of each species, but not the weighting factor g . The Pantle-Buck saprobity index S , ranging from 0 to 4, is thus calculated:
where the abundance A is expressed as one of nine subjective categories, ranging from "very rare" to "mass development". It does not require the organisms to be counted – which can save a lot of time – but raises the issues of intra- and inter-rater reliability . [ 1 ]
The saprobic index is only regarded as a valid estimate if the sum of the abundance classes is at least 20. For example, if a survey only found a total of 500 individuals of any species, the sample would still be valid if the survey found four species with 125 individuals each (abundance class 5).
Likewise, a single water body has to be surveyed several times in different months in order to account for fluctuations.
During its history, several correcting factors have been introduced. For example, they deal with the flow rate of the river (fast-flowing water bodies are inherently better oxygenated, thus speeding up organic matter degradation), water acidification , and human-made changes to the water body. Likewise, corrections must be applied for the altitude of the ecosystem (lowland rivers naturally carry more organic matter than mountainous ones, where biomass production is lower), and for the different size of catchment areas . [ 4 ]
The saprobic system was never designed to accurately indicate water quality if only a selection of organisms is surveyed. Deviations can be sizeable if a survey only studies ciliates and members of the macrozoobenthos ( benthos animals larger than 1 millimeter), as the latter's abundance can be easily influenced by oxygen levels and not by the availability of organic matter. [ 5 ]
The saprobic system has a long history in German-language countries. The idea of saprobes to estimate water quality has been foreshadowed by the works of Arthur Hill Hassall (1850) and Ferdinand Julius Cohn (1853). In a series of publications, the Germans botanists Richard Kolkwitz and Maximilian Marsson (1902, 1908, 1909) have developed the saprobic system to judge water quality. [ 4 ] They compiled a list of about 300 plant and 500 animal species (excluding fish), and estimated saprobic values for them. [ citation needed ]
In 1955, H. Knöpp introduced abundance classes, and the calculation of a water quality index was established during the 1950s and 1960s (Pantle & Buck, 1955; Zelinka & Marvan, 1961; Marvan, 1969). [ 4 ]
In 2000, the Pantle & Buck technique has been criticized because it requires the surveyed organisms to be identified by genus , something that freshwater ecologists are rarely trained for. Furthermore, it focuses on aquatic organisms that are prevalent in Western Europe, something that hampers water quality assays in Eastern Europe and Asia. [ 6 ]
The procedure used in Germany to estimate the saprobic index has been standardized in DIN 38410. [ 7 ] | https://en.wikipedia.org/wiki/Saprobic_system |
Saprobionts are organisms that digest their food externally and then absorb the products. [ 1 ] [ 2 ] This process is called saprotrophic nutrition . Fungi are examples of saprobiontic organisms, which are a type of decomposer . [ citation needed ]
Saprobiontic organisms feed off dead and/or decaying biological materials. Digestion is accomplished by excretion of digestive enzymes which break down cell tissues, allowing saprobionts to extract the nutrients they need while leaving the indigestible waste. This is called extracellular digestion . This is very important in ecosystems, for the nutrient cycle . [ citation needed ]
Saprobionts should not be confused with detritivores, another class of decomposers which digest internally. [ citation needed ]
These organisms can be good sources of extracellular enzymes for industrial processes such as the production of fruit juice. For instance, the fungus Aspergillus niger is used to produce pectinase , an enzyme which is used to break down pectin in juice concentrates, making the juice appear more translucent . | https://en.wikipedia.org/wiki/Saprobiont |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.