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SQUID Thus, the current changes direction periodically, every time the flux increases by additional half-integer multiple of formula_9, with a change at maximum amperage every half-plus-integer multiple of formula_9 and at zero amps every integer multiple. If the input current is more than formula_7, then the always op... | https://en.wikipedia.org/wiki?curid=46178 |
SQUID It is based on the AC Josephson effect and uses only one Josephson junction. It is less sensitive compared to DC but is cheaper and easier to manufacture in smaller quantities. Most fundamental measurements in biomagnetism, even of extremely small signals, have been made using RF SQUIDS. The RF is inductively cou... | https://en.wikipedia.org/wiki?curid=46178 |
SQUID In 2006, A proof of concept was shown for CNT-sensors built with an aluminium loop and a single walled carbon nanotube Josephson junction. The sensors are a few 100 nm in size and operate at 1K or below. Such sensors allow to count spins. The extreme sensitivity of SQUIDs makes them ideal for studies in biology. ... | https://en.wikipedia.org/wiki?curid=46178 |
SQUID Such device allows simultaneous measurement of roughness of the surface of a sample and the local magnetic flux. For example, SQUIDs are being used as detectors to perform magnetic resonance imaging (MRI). While high-field MRI uses precession fields of one to several teslas, SQUID-detected MRI uses measurement fi... | https://en.wikipedia.org/wiki?curid=46178 |
SQUID The use of SQUIDs in oil prospecting, mineral exploration, earthquake prediction and geothermal energy surveying is becoming more widespread as superconductor technology develops; they are also used as precision movement sensors in a variety of scientific applications, such as the detection of gravitational waves... | https://en.wikipedia.org/wiki?curid=46178 |
SQUID After removal of the magnetizing field, the nanoparticles decay from a ferromagnetic state to a paramagnetic state, with a time constant that depends upon the particle size and whether they are bound to an external surface. Measurement of the decaying magnetic field by sensors is used to detect and localize the n... | https://en.wikipedia.org/wiki?curid=46178 |
Butter is a dairy product made from the fat and protein components of milk or cream. It is a semi-solid emulsion at room temperature, consisting of approximately 80% butterfat. It is used at room temperature as a spread, melted as a condiment, and used as an ingredient in baking, sauce making, pan frying, and other coo... | https://en.wikipedia.org/wiki?curid=46183 |
Butter This may be a compound of βοῦς ("bous"), "ox, cow" + τυρός ("turos"), "cheese", that is "cow-cheese". The word "turos" ("cheese") is attested in Mycenaean Greek. The unlatinized form is found in the name butyric acid, a compound found in rancid butter and dairy products such as Parmesan cheese. In general use, t... | https://en.wikipedia.org/wiki?curid=46183 |
Butter contains fat in three separate forms: free butterfat, butterfat crystals, and undamaged fat globules. In the finished product, different proportions of these forms result in different consistencies within the butter; butters with many crystals are harder than butters dominated by free fats. Churning produces sma... | https://en.wikipedia.org/wiki?curid=46183 |
Butter Before modern factory butter making, cream was usually collected from several milkings and was therefore several days old and somewhat fermented by the time it was made into butter. made from a fermented cream is known as cultured butter. During fermentation, the cream naturally sours as bacteria convert milk su... | https://en.wikipedia.org/wiki?curid=46183 |
Butter Production of sweet cream butter first became common in the 19th century, with the development of refrigeration and the mechanical cream separator. made from fresh or cultured unpasteurized cream is called raw cream butter. While butter made from pasteurized cream may keep for several months, raw cream butter ha... | https://en.wikipedia.org/wiki?curid=46183 |
Butter Either granular salt or a strong brine are added to salted butter during processing. In addition to enhanced flavor, the addition of salt acts as a preservative. The amount of butterfat in the finished product is a vital aspect of production. In the United States, products sold as "butter" must contain at least ... | https://en.wikipedia.org/wiki?curid=46183 |
Butter They are also cheaper than "sweet" cream and butter. The fat content of whey is low, so 1000 pounds of whey will typically give 3 pounds of butter. There are several butters produced in Europe with protected geographical indications; these include: The earliest butter would have been from sheep or goat's milk; c... | https://en.wikipedia.org/wiki?curid=46183 |
Butter Ghee is mentioned in the Periplus of the Erythraean Sea as a typical trade article around the first century CE Arabian Sea, and Roman geographer Strabo describes it as a commodity of Arabia and Sudan. In India, ghee has been a symbol of purity and an offering to the gods—especially Agni, the Hindu god of fire—fo... | https://en.wikipedia.org/wiki?curid=46183 |
Butter The "Tower" of Rouen Cathedral was erected in the early 16th century when Archbishop Georges d'Amboise authorized the burning of butter instead of oil, which was scarce at the time, during Lent. Across northern Europe, butter was sometimes treated in a manner unheard-of today: it was packed into barrels (firkins... | https://en.wikipedia.org/wiki?curid=46183 |
Butter Until the 19th century, the vast majority of butter was made by hand, on farms. The first butter factories appeared in the United States in the early 1860s, after the successful introduction of cheese factories a decade earlier. In the late 1870s, the centrifugal cream separator was introduced, marketed most suc... | https://en.wikipedia.org/wiki?curid=46183 |
Butter These and other ADSA publications helped standardize practices internationally. also provided extra income to farm families. They used wood presses with carved decoration to press butter into pucks or small bricks to sell at nearby markets or general stores. The decoration identified the farm that produced the b... | https://en.wikipedia.org/wiki?curid=46183 |
Butter stick wrappers are usually marked with divisions for , which is less than their actual volume: the Elgin-pack shape is , while the Western-pack shape is . The printing on unsalted ("sweet") butter wrappers is typically red, while that for salted butter is typically blue. Outside of the United States, the shape o... | https://en.wikipedia.org/wiki?curid=46183 |
Butter "Smen" is a spiced Moroccan clarified butter, buried in the ground and aged for months or years. A similar product is "maltash" of the Hunza Valley, where cow and yak butter can be buried for decades, and is used at events such as weddings. Yak butter is a specialty in Tibet; "tsampa", barley flour mixed with ya... | https://en.wikipedia.org/wiki?curid=46183 |
Butter "French butter dishes" or "Acadian butter dishes" have a lid with a long interior lip, which sits in a container holding a small amount of water. Usually the dish holds just enough water to submerge the interior lip when the dish is closed. is packed into the lid. The water acts as a seal to keep the butter fres... | https://en.wikipedia.org/wiki?curid=46183 |
Butter Hollandaise and béarnaise sauces are emulsions of egg yolk and melted butter; they are in essence mayonnaises made with butter instead of oil. Hollandaise and béarnaise sauces are stabilized with the powerful emulsifiers in the egg yolks, but butter itself contains enough emulsifiers—mostly remnants of the fat g... | https://en.wikipedia.org/wiki?curid=46183 |
Butter fills several roles in baking, where it is used in a similar manner as other solid fats like lard, suet, or shortening, but has a flavor that may better complement sweet baked goods. Many cookie doughs and some cake batters are leavened, at least in part, by creaming butter and sugar together, which introduces a... | https://en.wikipedia.org/wiki?curid=46183 |
Refrigeration is a process that removes heat from a space, substance, or system to lower and/or maintain its temperature below the ambient temperature. In other words, refrigeration is artificial (human-made) cooling. Energy in the form of heat is removed from a low-temperature reservoir and transferred to a high-tempe... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration These new settlement patterns sparked the building of large cities which are able to thrive in areas that were otherwise thought to be inhospitable, such as Houston, Texas, and Las Vegas, Nevada. In most developed countries, cities are heavily dependent upon refrigeration in supermarkets in order to obtai... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration The next ancient society to record the harvesting of ice may have been the Jews in the book of Proverbs, which reads, “As the cold of snow in the time of harvest, so is a faithful messenger to them who sent him.” Historians have interpreted this to mean that the Jews used ice to cool beverages rather than... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration This would allow many perishables such as fruit, butter, and cured meats to be kept that would normally spoil in the heat. Before 1830, few Americans used ice to refrigerate foods due to a lack of ice-storehouses and iceboxes. As these two things became more widely available, individuals used axes and saw... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration In New York City, ice consumption increased from 12,000 tons in 1843 to 100,000 tons in 1856. Boston's consumption leapt from 6,000 tons to 85,000 tons during that same period. Ice harvesting created a “cooling culture” as majority of people used ice and iceboxes to store their dairy products, fish, meat,... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration They noted that soon after they passed the freezing point of water (32 °F), a thin film of ice formed on the surface of the thermometer's bulb and that the ice mass was about a quarter inch thick when they stopped the experiment upon reaching . Franklin wrote, "From this experiment, one may see the possib... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration The first practical vapour-compression refrigeration system was built by James Harrison, a British journalist who had emigrated to Australia. His 1856 patent was for a vapour-compression system using ether, alcohol, or ammonia. He built a mechanical ice-making machine in 1851 on the banks of the Barwon Ri... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration His new process made possible using gases such as ammonia, sulfur dioxide (SO) and methyl chloride (CHCl) as refrigerants and they were widely used for that purpose until the late 1920s. Thaddeus Lowe, an American balloonist, held several patents on ice-making machines. His "Compression Ice Machine" would... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration , which went on to produce the first commercial ice-makers in the US. By the 1870s breweries had become the largest users of harvested ice. Though the ice-harvesting industry had grown immensely by the turn of the 20th century, pollution and sewage had begun to creep into natural ice, making it a problem ... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration William Soltau Davidson thought that Britain's rising population and meat demand could mitigate the slump in world wool markets that was heavily affecting New Zealand. After extensive research, he commissioned the "Dunedin" to be refitted with a compression refrigeration unit for meat shipment in 1881. On... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration The meat-packing industry relied heavily on natural ice in the 1880s and continued to rely on manufactured ice as those technologies became available. By 1900, the meat-packing houses of Chicago had adopted ammonia-cycle commercial refrigeration. By 1914 almost every location used artificial refrigeration... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration During the early 1800s consumers preserved their food by storing food and ice purchased from ice harvesters in iceboxes. In 1803, Thomas Moore patented a metal-lined butter-storage tub which became the prototype for most iceboxes. These iceboxes were used until nearly 1910 and the technology did not progr... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration Freon is a trademark of the DuPont Corporation and refers to these CFCs, and later hydro chlorofluorocarbon (HCFC) and hydro fluorocarbon (HFC), refrigerants developed in the late 1920s. These refrigerants were considered at the time to be less harmful than the commonly-used refrigerants of the time, incl... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration The refrigerated rail car (refrigerated van or refrigerator car), along with the dense railroad network, became an exceedingly important link between the marketplace and the farm allowing for a national opportunity rather than a just a regional one. Before the invention of the refrigerated rail car it was... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration During World War I, a national refrigerator car pool was established by the United States Administration to deal with problem of idle cars and was later continued after the war. The idle car problem was the problem of refrigeration cars sitting pointlessly in between seasonal harvests. This meant that ver... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration New agricultural opportunity presented itself in areas that were considered rural such as states in the south and in the west. Shipments on a large scale from the south and California were both made around the same time although natural ice was used from the Sierras in California rather than manufactured ... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration made production possible in the west far from eastern markets, so much in fact that dairy farmers could pay transportation cost and still undersell their eastern competitors. and the refrigerated rail gave opportunity to areas with rich soil far from natural channel of transport such as a river, valley tr... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration The rapid growth of these cities was influenced by refrigeration and an agricultural productivity increase, allowing more distant farms to effectively feed the population. Agriculture's role in developed countries has drastically changed in the last century due to many factors, including refrigeration. St... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration Yet, while the United States population has continued to climb, citizens pursuing agriculture continue to decline. Based on the 2007 US Census, less than one percent of a population of 310 million people claim farming as an occupation today. However, the increasing population has led to an increasing dema... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration In the United States, the Meat Inspection Act of 1891 was put in place in the United States because local butchers felt the refrigerated railcar system was unwholesome. When meat packing began to take off, consumers became nervous about the quality of the meat for consumption. Upton Sinclair's 1906 novel ... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration In just a few years, 300,000 people in rural areas of the United States had received power in their homes. While electricity dramatically improved working conditions on farms, it also had a large impact on the safety of food production. systems were introduced to the farming and food distribution processe... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration Refrigerators have led to a huge increase in meat and dairy products as a portion of overall supermarket sales. As well as changing the goods purchased at the market, the ability to store these foods for extended periods of time has led to an increase in leisure time. Prior to the advent of the household ... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration Recent studies have also shown a negative relationship between the number of refrigerators in a household and the rate of gastric cancer mortality. Probably the most widely used current applications of refrigeration are for air conditioning of private homes and public buildings, and refrigerating foodstuf... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration Dairy products are constantly in need of refrigeration, and it was only discovered in the past few decades that eggs needed to be refrigerated during shipment rather than waiting to be refrigerated after arrival at the grocery store. Meats, poultry and fish all must be kept in climate-controlled environme... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration This consists of a refrigeration cycle, where heat is removed from a low-temperature space or source and rejected to a high-temperature sink with the help of external work, and its inverse, the thermodynamic power cycle. In the power cycle, heat is supplied from a high-temperature source to the engine, pa... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration Cyclic refrigeration can be classified as: Vapor cycle refrigeration can further be classified as: The vapor-compression cycle is used in most household refrigerators as well as in many large commercial and industrial refrigeration systems. Figure 1 provides a schematic diagram of the components of a typi... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration The resulting refrigerant vapor returns to the compressor inlet at point 1 to complete the thermodynamic cycle. The above discussion is based on the ideal vapor-compression refrigeration cycle, and does not take into account real-world effects like frictional pressure drop in the system, slight thermodyna... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration In the absorption system, the compressor is replaced by an absorber which dissolves the refrigerant in a suitable liquid, a liquid pump which raises the pressure and a generator which, on heat addition, drives off the refrigerant vapor from the high-pressure liquid. Some work is needed by the liquid pump ... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration In the gas cycle, the refrigeration effect is equal to the product of the specific heat of the gas and the rise in temperature of the gas in the low temperature side. Therefore, for the same cooling load, a gas refrigeration cycle needs a large mass flow rate and is bulky. Because of their lower efficienc... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration Peltier cooling only has 1/4 the efficiency of the vapor-compression cycle so it doesn't extract as much heat, emits more waste heat (heat generated by the peltier element or cooling mechanism) and consumes more power for a given cooling capacity. Magnetic refrigeration, or adiabatic demagnetization, is a... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration Other methods of refrigeration include the air cycle machine used in aircraft; the vortex tube used for spot cooling, when compressed air is available; and thermoacoustic refrigeration using sound waves in a pressurized gas to drive heat transfer and heat exchange; steam jet cooling popular in the early 1... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration Removing the stress reverses the process, restores the material to its austenitic phase, and absorbs heat from the surroundings cooling down the material. The most appealing part of this research is how potentially energy efficient and environmentally friendly this cooling technology is. The different mat... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration The Fridge Gate method is a theoretical application of using a single logic gate to drive a refrigerator in the most energy efficient way possible without violating the laws of thermodynamics. It operates on the fact that there are two energy states in which a particle can exist: the ground state and the ... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration The passive system, which could be used to supplement other cooling systems to preserve food and medications in hot, off-grid locations, is essentially a high-tech version of a parasol. The measured capacity of refrigeration is always dimensioned in units of power. Domestic and commercial refrigerators ma... | https://en.wikipedia.org/wiki?curid=46238 |
Refrigeration It is important to note that both CoP and PF for a refrigeration system are only defined at specific operating conditions, including temperatures and thermal loads. Moving away from the specified operating conditions can dramatically change a system's performance. | https://en.wikipedia.org/wiki?curid=46238 |
Otto Hahn (8 March 1879 – 28 July 1968) was a German chemist and pioneer in the fields of radioactivity and radiochemistry. In 1938, and Lise Meitner discovered nuclear fission (but only he received the Nobel Prize for the discovery). He is referred to as the father of nuclear chemistry. He was awarded the Nobel Prize ... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn At the age of 15, he began to take a special interest in chemistry, and carried out simple experiments in the laundry room of the family home. His father wanted Otto to study architecture, as he had built or acquired several residential and business properties, but Otto persuaded him that his ambition was to ... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn According to journalist Bernt Engelmann, Hahn was often thought of as Jewish because of his "Jewish sounding" surname, but he instead asserts that Hahn only had Jewish ancestors on his maternal side of the family despite "Giese" (his mother's maiden name) not being a traditional Jewish surname. Engelmann clai... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn The term "isotope" was only coined in 1913, by the British chemist Frederick Soddy). Ramsay was very enthusiastic when yet another new element was found in his institute, and he intended to announce the discovery in a correspondingly suitable way. In accordance with tradition this should be done before the co... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn " In his Rutherford biography, the BBC Science Correspondent David Wilson stated: In 1906, Hahn returned to Germany, where he collaborated with Emil Fischer at the University of Berlin. Fischer placed at his disposal a former woodworking shop ("Holzwerkstatt") in the Chemical Institute to use as his own labor... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn In 1914, for the discovery of mesothorium I (radium-228), was first nominated for the Nobel Prize in Chemistry by Adolf von Baeyer and, in June 1907, by means of the traditional "habilitation" thesis, Hahn qualified to teach at the University of Berlin. On 28 September 1907 he made the acquaintance of the Aus... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn In 1924, Hahn was elected to full membership of the Prussian Academy of Sciences in Berlin (proposed by Albert Einstein, Max Planck, Fritz Haber, Wilhelm Schlenk, and Max von Laue). In June 1911, while attending a conference in Stettin (today Szczecin, Poland) met the young Edith Junghans (1887–1968), an art ... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn He was a joyful participant in the Christmas truce of 1914 and was commissioned. In mid-January 1915 he was summoned to meet Fritz Haber, who explained their plan to break the trench deadlock with chlorine gas. After brief training in Berlin together with James Franck and Gustav Hertz, Hahn was sent to Flande... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn In 1918 the third German offensive in the west smashed through the Allied lines after a massive release of gas from their mortars the Germans reached the Marne. That summer Hahn was too weak to work, presumably poisoned by phosgene. At the end of the war he was in the field in mufti on a secret mission to tes... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn Gerlach remarked that this was "a discovery that was not understood at the time but later became highly significant for nuclear physics". Not until 1936 did Carl Friedrich von Weizsäcker provide a theoretical explanation of the phenomenon of nuclear isomerism. For this discovery, whose full significance was r... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn Seaborg, co-discoverer of many transuranium elements and President of the United States Atomic Energy Commission, wrote about this book as follows: And Seaborg added: Jointly with Lise Meitner and his pupil and assistant Fritz Strassmann (1902–1980), furthered the research begun by Enrico Fermi and his team i... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn On 13 July 1938, with the help and support of Hahn, Meitner – born into a Jewish family – escaped to the Netherlands; before she left, Hahn gave her a diamond ring he had inherited from his mother, to be used to bribe the frontier guards if required. Meitner emigrated to Stockholm, but continued to work with ... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn Hahn, who did not inform the physicists in his Institute, described the results exclusively in a letter to Meitner on 19 December: we are more and more coming to the awful conclusion that our Ra isotopes behave not like Ra, but like Ba. ... Perhaps you can suggest some fantastic explanation. We ourselves real... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn However, Meitner and her nephew, the young physicist Otto Robert Frisch, in Sweden, came to the same conclusion (a "bursting") as Hahn and were able, because they had a lead of time, to work out the first theoretical interpretation of nuclear fission – the term that was coined by Frisch, and which subsequentl... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn By 1945, he had drawn up a list of 25 elements and about 100 isotopes whose existence he had demonstrated. In 1944 his laboratory and office, with his files of correspondence, were destroyed by bombs, later that year the Chemistry Institute moved to southern Germany. At the end of World War II in 1945, Hahn w... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn " On January 3, 1946, the group was allowed to return to Germany, and Hahn, Heisenberg, and von Laue were brought to the city of Göttingen, which was controlled by the British occupation authorities. On 15 November 1945 the Royal Swedish Academy of Sciences announced that Hahn had been awarded the 1944 Nobel ... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn But I believe that Otto Robert Frisch and I contributed something not insignificant to the clarification of the process of uranium fission – how it originates and that it produces so much energy, and that was something very remote from Hahn.Meitner's former assistant Carl Friedrich von Weizsäcker later added:... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn " From 1948 to 1960 was the founding President of the newly formed Max Planck Society for the Advancement of Science, which through his tireless activity and his worldwide respected personality succeeded in regaining the renown once enjoyed by the Kaiser Wilhelm Society. Lawrence Badash wrote: Sir James Chadw... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn The next year Hahn initiated and organized the Mainau Declaration of 1955, in which he and a number of international Nobel Prize-winners called attention to the dangers of atomic weapons and warned the nations of the world urgently against the use of "force as a final resort", and which was issued a week afte... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn In October, together with Clement Attlee, Edgar Faure, Tetsu Katayama, et al. he signed the international "Agreement to call a meeting to draw up a world constitution". Since 1958, Hahn was sending messages to the annual conferences of the recently founded "Japan Council Against A and H Bombs" in Tokyo. In 19... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn " During his lifetime Hahn was awarded orders, medals, scientific prizes, and fellowships of Academies, Societies, and Institutions from all over the world. A selection: In 1957, Hahn was elected an honorary citizen of the city of Magdeburg, DDR (German Democratic Republic) and, in 1958, an honorary member of... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn Proposals were made at different times, first in 1971 by American chemists, that the newly synthesized element no. 105 should be named hahnium in Hahn's honor; in 1997 the IUPAC (International Union of Pure and Applied Chemistry) named it dubnium, after the Russian research center in Dubna (see element naming... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn More than twenty states worldwide have honored by issuing coins, medals or stamps with his portrait. An island in the Antarctic (near Mt. Discovery) was also named after him, as were two Intercity trains "Otto Hahn" of the German Federal Railways in 1971, running between Hamburg and Basel SBB, and the "Librar... | https://en.wikipedia.org/wiki?curid=46825 |
Otto Hahn In this poll the experimental chemist – after the theoretical physicists Albert Einstein and Max Planck – was elected third (with 81 points), and thus the most significant empiric researcher of his time. | https://en.wikipedia.org/wiki?curid=46825 |
Buffer solution A buffer solution (more precisely, pH buffer or hydrogen ion buffer) is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or base is added to it. Buffer solutions are used as a means of keeping ... | https://en.wikipedia.org/wiki?curid=46999 |
Buffer solution The hydrogen ion concentration decreases by less than the amount expected because most of the added hydroxide ion is consumed in the reaction and only a little is consumed in the neutralization reaction (which is the reaction that results in an increase in pH) Once the acid is more than 95% deprotonated... | https://en.wikipedia.org/wiki?curid=46999 |
Buffer solution In biological systems this is an essential condition for enzymes to function correctly. For example, in human blood a mixture of carbonic acid (HCO) and bicarbonate (HCO) is present in the plasma fraction; this constitutes the major mechanism for maintaining the pH of blood between 7.35 and 7.45. Outsid... | https://en.wikipedia.org/wiki?curid=46999 |
Buffer solution By combining substances with p"K" values differing by only two or less and adjusting the pH, a wide range of buffers can be obtained. Citric acid is a useful component of a buffer mixture because it has three p"K" values, separated by less than two. The buffer range can be extended by adding other buffe... | https://en.wikipedia.org/wiki?curid=46999 |
Buffer solution The second row, labelled C for "change", specifies the changes that occur when the acid dissociates. The acid concentration decreases by an amount −"x", and the concentrations of A and H both increase by an amount +"x". This follows from the equilibrium expression. The third row, labelled E for "equilib... | https://en.wikipedia.org/wiki?curid=46999 |
Buffer solution In the case of citric acid, this entails the solution of the two equations of mass balance: "C" is the analytical concentration of the acid, "C" is the analytical concentration of added hydrogen ions, "β" are the cumulative association constants: "K" is the constant for self-ionization of water. There a... | https://en.wikipedia.org/wiki?curid=46999 |
Arrhenius equation In physical chemistry, the is a formula for the temperature dependence of reaction rates. The equation was proposed by Svante Arrhenius in 1889, based on the work of Dutch chemist Jacobus Henricus van 't Hoff who had noted in 1884 that van 't Hoff equation for the temperature dependence of equilibriu... | https://en.wikipedia.org/wiki?curid=47011 |
Arrhenius equation The units of the pre-exponential factor are identical to those of the rate constant and will vary depending on the order of the reaction. If the reaction is first order it has the units: s, and for that reason it is often called the "frequency factor" or "attempt frequency" of the reaction. Most simp... | https://en.wikipedia.org/wiki?curid=47011 |
Arrhenius equation So, when a reaction has a rate constant that obeys Arrhenius equation, a plot of ln "k" versus "T" gives a straight line, whose gradient and intercept can be used to determine "E" and "A" . This procedure has become so common in experimental chemical kinetics that practitioners have taken to using it... | https://en.wikipedia.org/wiki?curid=47011 |
Arrhenius equation Arrhenius argued that for reactants to transform into products, they must first acquire a minimum amount of energy, called the activation energy "E". At an absolute temperature "T", the fraction of molecules that have a kinetic energy greater than "E" can be calculated from statistical mechanics. The... | https://en.wikipedia.org/wiki?curid=47011 |
Arrhenius equation However for many reactions this agrees poorly with experiment, so the rate constant is written instead as formula_15. Here "P" is an empirical steric factor, often much less than 1, which is interpreted as the fraction of sufficiently energetic collisions in which the two molecules have the correct m... | https://en.wikipedia.org/wiki?curid=47011 |
Arrhenius equation Both the Arrhenius activation energy and the rate constant "k" are experimentally determined, and represent macroscopic reaction-specific parameters that are not simply related to threshold energies and the success of individual collisions at the molecular level. Consider a particular collision (an e... | https://en.wikipedia.org/wiki?curid=47011 |
Phosgene is the organic chemical compound with the formula COCl. It is a colorless gas; in low concentrations, its odor resembles freshly cut hay or grass. is a valued industrial building block, especially for the production of urethanes and polycarbonate plastics. However, it is very poisonous and was used as a chemic... | https://en.wikipedia.org/wiki?curid=47107 |
Phosgene Although less dangerous than many other chemical weapons such as sarin, phosgene is still regarded as a viable chemical warfare agent because it is so easy to manufacture when compared to the production requirements of more technically advanced chemical weapons such as the first-generation nerve agent tabun. U... | https://en.wikipedia.org/wiki?curid=47107 |
Phosgene No valid statistics are available, but anecdotal reports suggest that numerous refrigeration technicians suffered the effects of phosgene poisoning due to their ignorance of the toxicity of phosgene, produced during such leak testing. Electronic sensing of refrigerant gases phased out the use of flame testing ... | https://en.wikipedia.org/wiki?curid=47107 |
Phosgene The great majority of phosgene is used in the production of isocyanates, the most important being toluene diisocyanate (TDI) and methylene diphenyl diisocyanate (MDI). These two isocyanates are precursors to polyurethanes. The reaction of an organic substrate with phosgene is called phosgenation. Significant a... | https://en.wikipedia.org/wiki?curid=47107 |
Phosgene Thionyl chloride is more commonly and more safely employed for this application. A specific application for phosgene is the production of chloroformic esters: is stored in metal cylinders. The outlet is always standard, a tapered thread that is known as CGA 160 Although it is somewhat hydrophobic, phosgene rea... | https://en.wikipedia.org/wiki?curid=47107 |
Phosgene Three hundred people were poisoned, of whom 10 died. was then only infrequently used by the Imperial Japanese Army against the Chinese during the Second Sino-Japanese War. Gas weapons, such as phosgene, were produced by Unit 731 and authorized by specific orders given by Hirohito (Emperor Showa) himself, trans... | https://en.wikipedia.org/wiki?curid=47107 |
Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. The process of biodegradation can be divided into three stages: biodeterioration, biofragmentation, and assimilation. Biodeterioration is sometimes described as a surface-level degradation that modifies the mechanical, phys... | https://en.wikipedia.org/wiki?curid=47490 |
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