As the decade went on, we had become supersaturated with superheroics.
|
|
" Mr. Vanunu: "This season, it's all about a bold, but sophisticated, supersaturated color.
|
|
Television broadcasts are supersaturated with ads for expensive pick-up trucks and beers.
|
|
The orbiter revealed that parts of the atmosphere actually act like pockets, reaching supersaturated level.
|
|
More familiar, but just as transporting, was the risotto, supersaturated with brown butter and creamy Castelmagno cheese.
|
|
Ms. Jolie, working with the cinematographer Anthony Dod Mantle, shoots the character's dream sequences in garish, supersaturated colors.
|
|
"Cream products can drag on the skin and deposit supersaturated color that's more difficult to blend out," Mr. Surratt said.
|
|
Media attention is also a huge factor in generating contributions, and the supersaturated coverage that greeted Harvey and Irma tapered for Maria.
|
|
In a time when hip hop is supersaturated with vapid pop hits and petty feuds, Lamar is socially resonant and musically gifted.
|
|
It's into this supersaturated entertainment age that Amazon's The Boys enters, sleeves rolled up and looking for a bit of the old ultraviolence.
|
|
Since diving into the late French photographer's archives last year, I've come to terms with the fact that I don't live in his glamorous, supersaturated world.
|
|
The clothes were in bright, supersaturated colors printed with trompe-l'oeil shadow effects, as if the model had stepped out of a Dick Tracy comic strip.
|
|
Modernism had won the fight against ornament, and Makeig-Jones's creatures and the supersaturated mythical bower they inhabited fell from fashion as quickly as they had risen.
|
|
Finely rendered gummy bears, avalanches of soft serve, the supersaturated palette of the candy store, and a direct lining tapping into our collective childhoods are Magruder's active ingredients.
|
|
Opinion Columnist The campaign for governor of Georgia is a supersaturated microcosm of American politics right now, offering the starkest possible choice between irreconcilable visions of the country's future.
|
|
What the candidates may not want to hear, though, is that much of this money may be going to waste, especially during the supersaturated final days of the primary campaign.
|
|
Night after night, I watched Judith Light conjure the superannuated and supersaturated Palm Springs alcoholic Silda Grauman in my 2011 play, "Other Desert Cities," for which she won a Tony.
|
|
There was futuristic angularity and radically supersaturated color combinations in Bakst's work — electric blue swirled into sea-monster green on both the dancers' tutu-less outfits and the vivid Orientalist backdrops.
|
|
Most of these critters live in waters that are "supersaturated" with respect to calcium carbonate, making it easy for them to pull out the building blocks for their shells from those waters.
|
|
It was ultra-pretty, but there was also an edge to its soft breeziness, and the supersaturated color palette hinted at the beginning of greater changes to come: "My metamorphosis," he says now.
|
|
Out of all their songs, it's perhaps the one that bears the most resemblance to the output of PC Music, who obviously also use a lot of high, supersaturated vocals and uber-sweet production.
|
|
The other two programs were more lightly spiced with modernity: Saturday's with the dissonant angularity of Bartok's "Miraculous Mandarin" Suite (1927) and Sunday's with the supersaturated chromaticism of Schoenberg's "Verklärte Nacht" ("Transfigured Night"; 1917, revised 1943).
|
|
Lying in a supersaturated solution of magnesium sulfate — better known as Epsom salts — cranked up to body temperature, I pulled the top down over me and pushed the button to extinguish the violet light illuminating the pod.
|
|
Muse: Mickalene Thomas Photographs and tête-à-tête, now on view at the Aperture Foundation, focuses on the artist's dazzling, supersaturated photographs, taken over the past 15 years, as well as the work of her creative influences.
|
|
The landscape of food writing is supersaturated these days, and yet I still believe that at its best it can offer meaningful insights into what it means to be human, on par with what we get from the best novels.
|
|
The book begins, and races along, as an antic thriller, through a circus's worth of set pieces (sex dolls, lawn flamingoes, motorized wheelchairs, bestiality with dolphins), but throughout and underneath this supersaturated masquerade Hazel tells the darkest, baldest, saddest truths.
|
|
They capture scenes from this land of 1.2 billion in brilliant, supersaturated colors: monsoon-flooded Bengali villages; Rajasthani desert dust storms; green-painted men crowd surfing at a Holi festival; Hindu pilgrims visiting shrines on the River Ganges; steam engines chugging past the Taj Mahal.
|
|
Lisa Sanditz, whose palette is generally vibrant if not supersaturated, delivers a gem with "Cleared Lot" (7113), a 16 x 20 inch painting depicting a muddy-gray heap of earth and garbage out of which grows a spunky tree at an impossibly rakish angle.
|
|
The soft blush-nude known as "Millennial Pink" has achieved a supersaturated status in the marketing world, and a coating of the hue instantly transforms even the most blasé of products into a cool girl's must-have consumer item (or does that peachy-pink trash can really say something about you as an individual?).
|
|
Gas bubble disease is caused by contact with supersaturated water.
|
|
However, the performance of the method may be affected by the formation supersaturated solutions.
|
|
The identification of supersaturated solutions can be used as a tool for marine ecologists to study the activity of organisms and populations. Photosynthetic organisms release O2 gas into the water. Thus, an area of the ocean supersaturated with O2 gas can likely determined to be rich with photosynthetic activity. Though some O2 will naturally be found in the ocean due to simple physical chemical properties, upwards of 70% of all oxygen gas found in supersaturated regions can be attributed to photosynthetic activity.
|
|
A travertine terrace is formed when geothermally heated supersaturated alkaline waters emerge to the surface and form waterfalls of precipitated carbonates.
|
|
Impurities remain in the supernatant liquid. In some cases crystals do not form quickly and the solution remains supersaturated after cooling. This is because there is a thermodynamic barrier to the formation of a crystal in a liquid medium. Commonly this is overcome by adding a tiny crystal of the solute compound to the supersaturated solution, a process known as "seeding".
|
|
It was there that Partington met a student named Marian Jones whom he taught and supervised for a master's degree in supersaturated solutions.M. Jones & J. R. Partington, "Experiments on Supersaturated Solutions," Trans. Chem. Soc., 1915 Partington married her after the war on 6 September 1919. She went on to become a chemistry teacher before giving birth to two daughters and one son, who also became a chemist.
|
|
Basically, during an eruption the magma loses more carbon dioxide than water, that in the chamber is already supersaturated. Overall, water is the main volatile during an eruption.
|
|
If the nucleation starts later when the magma is very supersaturated, the distance between bubbles becomes smaller. Essentially if the magma rises rapidly to the surface, the system will be more out of equilibrium and supersaturated. When the magma rises there is competition between adding new molecules to the existing ones and creating new ones. The distance between molecules characterizes the efficiency of volatiles to aggregate to the new or existing site.
|
|
One may also speak of solid solution, but rarely of solution in a gas (see vapor–liquid equilibrium instead). Under certain conditions, the equilibrium solubility can be exceeded to give a so-called supersaturated solution, which is metastable. Metastability of crystals can also lead to apparent differences in the amount of a chemical that dissolves depending on its crystalline form or particle size. A supersaturated solution generally crystallises when 'seed' crystals are introduced and rapid equilibration occurs.
|
|
However, in other alloys, the insoluble elements may not separate until after crystallization occurs. If cooled very quickly, they first crystallize as a homogeneous phase, but they are supersaturated with the secondary constituents. As time passes, the atoms of these supersaturated alloys can separate from the crystal lattice, becoming more stable, and forming a second phase that serves to reinforce the crystals internally. Some alloys, such as electrum—an alloy of silver and gold—occur naturally.
|
|
Hobbs, P.V. 1974. Ice Physics. Oxford: Clarendon Press. Each flake nucleates around a dust particle in supersaturated air masses by attracting supercooled cloud water droplets, which freeze and accrete in crystal form.
|
|
Typically a temperature difference between the ice surface and the air of at least 15 °C is required, though this can be reduced if the air is very humid. In these conditions a layer of supersaturated vapour occurs due to the "surface skim" providing excess water vapor. As the warmer, wet air meets the overlying cold air it becomes supersaturated and condenses allowing small crystals to form a nucleus on the sea ice surface's imperfections and grow by vapor deposition.
|
|
A hand warmer containing a supersaturated solution of sodium acetate which releases heat upon crystallization Sodium acetate is also used in heating pads, hand warmers, and hot ice. Sodium acetate trihydrate crystals melt at 136.4 °F/58 °C (to 137.12 °F/58.4 °C),Courty JM, Kierlik E, Les chaufferettes chimiques, Pour la Science, décembre 2008, pp. 108–110 dissolving in their water of crystallization. When they are heated past the melting point and subsequently allowed to cool, the aqueous solution becomes supersaturated.
|
|
Caphosol refers to two different preparations. An effervescent dispersible tablet or two separately packaged aqueous solutions, a phosphate solution (Caphosol A) and a calcium solution (Caphosol B) which, when combined in equal volumes, forms a supersaturated solution of both calcium and phosphate ions. It is doubtful that the effervescent tablet can achieve a supersaturated solution of calcium and phosphate ions. Caphosol is usually used 4 times a day, but can be used up to 10 times a day when symptoms of mucositis are present.
|
|
Poured fondant is formed by supersaturating water with sucrose. More than twice as much sugar dissolves in water at the boiling point than at room temperature. After the sucrose dissolves, if the solution is left to cool undisturbed, the sugar remains dissolved in a supersaturated solution until nucleation occurs. While the solution is supersaturated, if a cook puts a seed crystal (undissolved sucrose) into the mix, or agitates the solution, the dissolved sucrose crystallizes to form large, crunchy crystals (which is how rock candy is made).
|
|
Chemical sedimentary rock forms when mineral constituents in solution become supersaturated and inorganically precipitate. Common chemical sedimentary rocks include oolitic limestone and rocks composed of evaporite minerals, such as halite (rock salt), sylvite, baryte and gypsum.
|
|
These grains are seen to crystallize from the liquid of a meteorite body where there are low amounts of chromium and oxygen. The large grains are associated with stable supersaturated conditions seen from the meteorite body.
|
|
Supersaturation of methane in oxygenated, near-surface ocean water is a phenomenon which has been widely observed, but which is still poorly understood. Methane is often 10–75% supersaturated in the oxygenated surface mixed-layer, causing the ocean to contribute methane to the atmosphere. One possible source for this supersaturated methane is the degradation of dissolved water-column methylphosphonate. The importance of the degradation of methylphosphonate in the production of CH4 in the ocean is likely variable and may be related to the availability of Fe, N, and P in the water column.
|
|
Some sort of ionizing radiation is needed. Methanol, isopropanol, or other alcohol vapor saturates the chamber. The alcohol falls as it cools down and the cold condenser provides a steep temperature gradient. The result is a supersaturated environment.
|
|
Centimeter-long crystals can be grown from a supersaturated solution of the molecules in toluene (ca. 2.5 mg/ml), which is slowly cooled (ca. 0.04 K/min) from 328 K to 298 K over a period of 12 hours.
|
|
Because microbial mats and shallow, supersaturated seas were necessary for the formation of this form of deposit, larger eukaryotic organisms could not survive in the regions in which these deposits were formed; hence the record is mainly restricted to bacteria.
|
|
Oxford University Press, Toronto. 1954, pp. 106-107 interpreted Gendron’s description as describing calcareous tufa, a rock formed by precipitation from supersaturated limestone deposits. Hunter,Hunter, James Erie Stone: A Seventeenth Iroquoian Medicinal Trading Commodity, Kewa 85-2:2-8.
|
|
Dissolved gases can be released during oil exploration when a strike is made. This occurs because the oil in oil-bearing rock is under considerable pressure from the over-lying rock, allowing the oil to be supersaturated with respect to dissolved gases.
|
|
A single-crystal quartz bar grown by the hydrothermal method KDP crystal grown from a seed crystal in a supersaturated aqueous solution at LLNL which is to be cut into slices and used on the National Ignition Facility for frequency doubling and tripling.
|
|
Knowledge of the automicrites generation processes allow to make paleo- environmental interpretations, so it can become good instrument for basin analysis. Carbonate mud or micrite may originate through several processes, including the abiotic precipitation from highly supersaturated seawater or precipitation induced by microbial activity.
|
|
Most of the time, the lake is stable and the remains in solution in the lower layers. However, over time, the water becomes supersaturated, and if an event such as an earthquake or landslide occurs, large amounts of may suddenly come out of solution.
|
|
As the solution cools, the solubility of the solute in the solvent will gradually become smaller. The resultant solution is described as supersaturated, meaning that there is more solute dissolved in the solution than would be predicted by its solubility at that temperature. Crystallization can then be induced from this supersaturated solution and the resultant pure crystals removed by such methods as vacuum filtration and centrifugal separators. The remaining solution, once the crystals have been filtered out, is known as the mother liquor, and will contain a portion of the original solute (as predicted by its solubility at that temperature) as well as any impurities that were not filtered out.
|
|
If the ambient pressure reduction is limited, this desaturation will take place in the dissolved phase, but if the ambient pressure is lowered sufficiently, bubbles may form and grow, both in blood and other supersaturated tissues. When the partial pressure of all gas dissolved in a tissue exceeds the total ambient pressure on the tissue it is supersaturated, and there is a possibility of bubble formation. The sum of partial pressures of the gas that the diver breathes must necessarily balance with the sum of partial pressures in the lung gas. In the alveoli the gas has been humidified and has gained carbon dioxide from the venous blood.
|
|
Supersaturated or supercooled liquids are also formed due to the fact that crystallization is being inhibited. They are unstable because crystallization is a favored reaction in this case. During the cooling process, the most important physicochemical characteristic of lollipops is occurring. This process is called glass transition.
|
|
They help prevent premature crystallization by inhibiting sucrose crystal contact. The fat also helps inhibit rapid crystallization. Controlling the crystallization of the supersaturated sugar solution is the key to making smooth fudge. Initiation of crystals before the desired time will result in fudge with fewer, larger sugar grains.
|
|
The Clovelly Dome Storage Terminal is used to store crude oil in underground salt domes before it is shipped to the various refineries. The terminal consists of eight caverns with a total capacity of , a pump station with four 6,000-hp pumps, meters to measure the crude oil receipts and deliveries, and a Brine Storage Reservoir. The brine reservoir is supersaturated with salts so as to prevent further degradation of the massive salt dome in which the eight caverns store the crude. This is because the supersaturated brine is much more dense than the crude oil, and as it is pumped into the caverns to push the crude to the surface and into the surface distribution systems.
|
|
Casein Phosphopepetide-Amorphus Calcium Phosphate (CPP-ACP) provides a supersaturated environment of calcium and phosphate on the enamel surface to enhance remineralisation in the form of toothpaste or sugar free chewing gum. Its clinical effectiveness is still debatable but may benefit those patients who complain of mild pain to external stimuli.
|
|
Physica 7, 284–304 (1940). It is unlikely, however, that new phases often arise by this fluctuation mechanism and the resultant spontaneous nucleation. Calculations show that the chance, e−ΔS/k, is usually too small. It is more likely that tiny dust particles act as nuclei in supersaturated vapours or solutions.
|
|
The precise mechanism of how sonar causes bubble formation is not known. It could be due to cetaceans panicking and surfacing too rapidly in an attempt to escape the sonar pulses. There is also a theoretical basis by which sonar vibrations can cause supersaturated gas to nucleate, forming bubbles (cavitation).
|
|
Modern travertine is formed from geothermally heated supersaturated alkaline waters, with raised pCO2 (see partial pressure). On emergence, waters degas CO2 due to the lower atmospheric pCO2, resulting in an increase in pH. Since carbonate solubility decreases with increased pH,Bialkowski, S.E. 2004. Use of Acid Distributions in Solubility Problems.
|
|
The second solution has the tetrapropylammonium cation that acts as a templating agent. The third solution is the source of silica, one of the basic building blocks for the framework structure of a zeolite. Mixing the three solutions produces supersaturated tetrapropylammonium ZSM-5, which can be heated to recrystallize and produce a solid.
|
|
Sugar crust, in chocolate confectionery, is a method to prepare liquid (often liqueur) filled chocolates. The solid sugar crust is formed from a supersaturated sugar solution with a filling of choice. The crust completely seals the filling, allowing it to be coated with a layer of chocolate in a process called enrobing.
|
|
The preservational mode is only present in the Precambrian, and is restricted to shallow or tidal waters. After this point, organisms such as sponges extracted silica from the oceans in order to construct tests (skeletons), with the result that the surface oceans no longer became supersaturated with respect to silica when evaporation condensed the mineral.
|
|
For example, although sucrose can be recrystallised easily, its hydrolysis product, known as "invert sugar" or "golden syrup" is a mixture of glucose and fructose that exists as a viscous, supersaturated, liquid. Clear honey contains carbohydrates which may crystallize over a period of weeks. Supersaturation may be encountered when attempting to crystallize a protein.
|
|
When measuring the concentration of a solute in a supersaturated gaseous or liquid mixture it is obvious that the pressure inside the cuvette may be greater than the ambient pressure. When this is so a specialized cuvette must be used. The choice of analytical technique to use will depend on the characteristics of the analyte.
|
|
A cloud chamber, also known as a Wilson cloud chamber, is a particle detector used for visualizing the passage of ionizing radiation. Fig. 1: Cloud chamber photograph used to prove the existence of the positron. Observed by C. Anderson. A cloud chamber consists of a sealed environment containing a supersaturated vapor of water or alcohol.
|
|
Carbonated sodas contain elevated levels of carbon dioxide under pressure. The solution becomes supersaturated with carbon dioxide when the bottle is opened, and the pressure is released. Under these conditions, carbon dioxide begins to precipitate from solution, forming gas bubbles. The activation energy for bubble nucleation (formation of bubbles) depends on where the bubble forms.
|
|
Only natural processes occur in nature. For thermodynamics, a natural process is a transfer between systems that increases the sum of their entropies, and is irreversible. Natural processes may occur spontaneously, or may be triggered in a metastable or unstable system, as for example in the condensation of a supersaturated vapour.Planck, M.(1897/1903).
|
|
The cycle of diffusion continues until the concentration of oxygen in the arterial capillaries is supersaturated (larger than the concentration of oxygen in the swim bladder). At this point, the free oxygen in the arterial capillaries diffuses into the swim bladder via the gas gland.Kardong, K. (2008). Vertebrates: Comparative anatomy, function, evolution, (5th ed.).
|
|
Ascent and descent are the phases of a dive where ambient pressure is changing, and this causes a number of hazards. Direct hazards include barotrauma, indirect hazards include buoyancy instability and physiological effects of gas solubility changes, mainly the risk of bubble formation by supersaturated inert gas in body tissues, known as decompression sickness.
|
|
The gas will not necessarily form bubbles in the solvent at this stage, but supersaturation is necessary for bubble growth. A supersaturated solution of gases in a tissue may form bubbles if suitable nucleation sites exist. Supersaturation may be defined as a sum of all gas partial pressures in the liquid which exceeds the ambient pressure in the liquid.
|
|
Bubble formation occurs in the blood or other tissues. One of the hypothetical loci of bubble nucleation is in crevices in macromolecules. A solvent can carry a supersaturated load of gas in solution. Whether it will come out of solution in the bulk of the solvent to form bubbles will depend on a number of factors.
|
|
The evolution of vesiculation can be summarized in these steps: # The magma becomes progressively saturated with volatiles when water and carbon dioxide dissolves in it. Nucleation of bubbles start when then magma is supersaturated with these volatiles. # Bubbles continue to grow by diffusive transfer of water gases from the magma. Stresses buildup inside the volcanic dome.
|
|
Calcium carbonate is deposited where evaporation of the water leaves a solution supersaturated with the chemical constituents of calcite. Tufa, a porous or cellular variety of travertine, is found near waterfalls. Coquina is a poorly consolidated limestone composed of pieces of coral or shells. During regional metamorphism that occurs during the mountain building process (orogeny), limestone recrystallizes into marble.
|
|
Kappe purchased the steep hillside lot in 1962 for $17,000. Designing a structure for the steep hillside was problematic, and Kappe designed six concrete towers supporting a glass- and-wood house. Built between 1965 and 1967, the house is raised on decks to avoid underground springs. The house features natural building materials, strong geometric form, and supersaturated colors.
|
|
The mechanism of formation starts with a small fragment of sediment acting as a 'seed', e.g., a piece of a shell. Strong intertidal currents wash the 'seeds' around on the seabed, where they accumulate layers of chemically precipitated calcite from the supersaturated water. The oolites are commonly found in large current bedding structures that resemble sand dunes.
|
|
The spa at Egerszalók is noted for its position in one of the principal wine-growing regions of Hungary. Egerszalók is also notable for human-caused geological morphology: when the spa was expanded by the government in 1961, the flow of supersaturated mineral water sharply increased, leading to the deposition of a hillside of shining white travertine.
|
|
In above-freezing temperatures the air would have to be supersaturated to around 400% before the droplets could form. The concept of cloud condensation nuclei is used in cloud seeding, which tries to encourage rainfall by seeding the air with condensation nuclei. It has further been suggested that creating such nuclei could be used for marine cloud brightening, a climate engineering technique.
|
|
Liquid–vapor equilibrium If the vapor pressure exceeds the equilibrium value, it becomes supersaturated and condenses on any available nucleation sites e. g. particles of dust. This principle is used in cloud chambers, where particles of radiation are visualized because they nucleate formation of water droplets. The vapor pressure is the equilibrium pressure from a liquid or a solid at a specific temperature.
|
|
Once a micro-bubble forms it may continue to grow if the tissues are still supersaturated. As the bubble grows it may distort the surrounding tissue and cause damage to cells and pressure on nerves resulting in pain, or may block a blood vessel, cutting off blood flow and causing hypoxia in the tissues normally perfused by the vessel. If a bubble or an object exists which collects gas molecules this collection of gas molecules may reach a size where the internal pressure exceeds the combined surface tension and external pressure and the bubble will grow. If the solvent is sufficiently supersaturated, the diffusion of gas into the bubble will exceed the rate at which it diffuses back into solution, and if this excess pressure is greater than the pressure due to surface tension the bubble will continue to grow.
|
|
Recrystallization is a process used to purify chemical compounds. A mixture of the impure compound and solvent is heated until the compound has dissolved. If there is some solid impurity remaining it is removed by filtration. When the temperature of the solution is subsequently lowered it briefly becomes supersaturated and then the compound crystallizes out until chemical equilibrium at the lower temperature is achieved.
|
|
A cloudburst is an extreme form of production of liquid water from a supersaturated mixture of air and water vapour in the atmosphere. Supersaturation in the vapour phase is related to the surface tension of liquids through the Kelvin equation, the Gibbs–Thomson effect and the Poynting effect.George N. Hatsopoulos & Joseph H. Keenan (1965), Principles of General Thermodynamics - John Wiley & Sons, Inc., New York, London, Sydney.
|
|
Chapter V, "The flow of steam through nozzles", pages 90 to 99 The study of supersaturation is also relevant to atmospheric studies. Since the 1940s, the presence of supersaturation in the atmosphere has been known. When water is supersaturated in the troposphere, the formation of ice lattices is frequently observed. In a state of saturation, the water particles will not form ice under tropospheric conditions.
|
|
Other carbonate grains composing limestones are ooids, peloids, intraclasts, and extraclasts. Limestone often contains variable amounts of silica in the form of chert (chalcedony, flint, jasper, etc.) or siliceous skeletal fragment (sponge spicules, diatoms, radiolarians), and travertine (a precipitate of calcite and aragonite). Secondary calcite may be deposited by supersaturated meteoric waters (groundwater that precipitates the material in caves). This produces speleothems, such as stalagmites and stalactites.
|
|
Modern dolomite formation has been found to occur under anaerobic conditions in supersaturated saline lagoons along the Rio de Janeiro coast of Brazil, namely, Lagoa Vermelha and Brejo do Espinho. It is often thought that dolomite will develop only with the help of sulfate- reducing bacteria (e.g. Desulfovibrio brasiliensis). However, low-temperature dolomite may occur in natural environments rich in organic matter and microbial cell surfaces.
|
|
This occurs from either added moisture in the air, or falling ambient air temperature. However, fog can form at lower humidities, and can sometimes fail to form with relative humidity at 100%. At 100% relative humidity, the air cannot hold additional moisture, thus, the air will become supersaturated if additional moisture is added. Fog commonly produces precipitation in the form of drizzle or very light snow.
|
|
Modern tufa is formed from alkaline waters, supersaturated with calcite. On emergence, waters degas CO2 due to the lower atmospheric pCO2 (see partial pressure), resulting in an increase in pH. Since carbonate solubility decreases with increased pH, precipitation is induced. Supersaturation may be enhanced by factors leading to a reduction in pCO2, for example increased air-water interactions at waterfalls may be important, as may photosynthesis.
|
|
The decay rate of the exponential gives the nucleation rate. Classical nucleation theory is a widely used approximate theory for estimating these rates, and how they vary with variables such as temperature. It correctly predicts that the time you have to wait for nucleation decreases extremely rapidly when supersaturated. It is not just new phases such as liquids and crystals that form via nucleation followed by growth.
|
|
The nutrient dissolves in the hotter zone and the saturated aqueous solution in the lower part is transported to the upper part by convective motion of the solution. The cooler and denser solution in the upper part of the autoclave descends while the counterflow of solution ascends. The solution becomes supersaturated in the upper part as the result of the reduction in temperature and crystallization sets in.
|
|
Moreover, below this temperature almost no Si is deposited on the growth surface. However, Au particles can form Au-Si eutectic droplets at temperatures above 363 °C and adsorb Si from the vapor state (because Au can form a solid-solution with all Si concentrations up to 100%) until reaching a supersaturated state of Si in Au. Furthermore, nanosized Au-Si droplets have much lower melting points (ref) because the surface area-to-volume ratio is increasing, becoming energetically unfavorable, and nanometer-sized particles act to minimize their surface energy by forming droplets (spheres or half-spheres). #Si has a much higher melting point (~1414 °C) than that of the eutectic alloy, therefore Si atoms precipitate out of the supersaturated liquid-alloy droplet at the liquid- alloy/solid-Si interface, and the droplet rises from the surface. This process is illustrated in figure 1.
|
|
There is a lack of good quality evidence for the efficacy of caphosol solution and the only systematic review is funded by the manufacturer and so carries an increased risk of bias.Quinn, B. (2013). Efficacy of a supersaturated calcium phosphate oral rinse for the prevention and treatment of oral mucositis in patients receiving high‐dose cancer therapy: a review of current data. European journal of cancer care, 22(5), 564-579.
|
|
The silicon content limits the solubility of zinc in copper in the α-phase. In the given alloy the maximum amount of silicon at a very high zinc content is added. The consequence is that the α-phase crystallized silicon supersaturated when it comes to high cooling rates of the alloy. As a result the α-solid solution does not disintegrate, which leads to the described high mechanical properties.
|
|
The essential of crystal formation is letting the sample solution to reach the supersaturated state. Supersaturation is defined by McPherson et al. 2014 as “a non-equilibrium condition in which some quantity of the macromolecule in excess of the solubility limit, under specific chemical and physical conditions, is nonetheless present in solution.” The formation of solids in solution, such as aggregation and crystals, favors the re-establishment of equilibrium.
|
|
If the magma contains less water than the maximum possible amount, it is undersaturated in water. Usually insufficient water and carbon dioxide exist in the deep crust and mantle, so magma is often undersaturated in these conditions. Magma becomes saturated when it reaches the maximum amount water that can be dissolved in it. If the magma continues to rise up to the surface and more water is dissolved, it becomes supersaturated.
|
|
What affects the behavior of the magmatic system is the depth at which carbon dioxide and water are released. Low solubility of carbon dioxide means that it starts to release bubbles before reaching the magma chamber. The magma is at this point already supersaturated. The magma enriched in carbon dioxide bubbles, rises up to the roof of the chamber and carbon dioxide tends to leak through cracks into the overlying caldera.
|
|
Gas bubble disease is a disease of fish that are exposed to water supersaturated with natural gases like oxygen, carbon dioxide, or nitrogen. It generally occurs in fish that live in aquariums and it becomes prominent whenever there is a change in temperature and pressure in natural environments, aquatic turbulence, and a disturbance in biotic metabolisms. Bubbles of gas may form in the eyes, skin, gills, and fins.
|
|
Supersaturation occurs with a chemical solution when the concentration of a solute exceeds the concentration specified by the value equilibrium solubility. Most commonly the term is applied to a solution of a solid in a liquid. A supersaturated solution is in a metastable state; it may be brought to equilibrium by forcing the excess of solute to separate from the solution. The term can also be applied to a mixture of gases.
|
|
One of the small scale uses of isopropanol is in cloud chambers. Isopropanol has ideal physical and chemical properties to form a supersaturated layer of vapor which can be condensed by particles of radiation. In 1990, 45,000 metric tonnes of isopropyl alcohol were used in the United States, mostly as a solvent for coatings or for industrial processes. In that year, 5400 metric tonnes were used for household purposes and in personal care products.
|
|
While CaCO3should precipitate spontaneously from seawater, which is supersaturated with respect to calcium carbonate, calcite precipitation is inhibited by the presence of Mg in seawater and aragonite crystallization is inhibited by organophosphatic molecules. In modern environments, carbonate mud seems to form spontaneously in seawater in whitings. Whitings are clouds of suspended carbonate crystals (aragonite and Mg-calcite) that make the sea white. This phenomenon is common in tropically environments such as the Great Bahama Bank.
|
|
The condensed water is called dew when it forms on a solid surface, or frost if it freezes. In the air, the condensed water is called either fog or a cloud, depending on its altitude when it forms. If the temperature is below the dew point, and no dew or fog forms, the vapor is called supersaturated. This can happen if there are not enough particles in the air to act as condensation nuclei.
|
|
The nucleation can occur thanks to the presence of solid crystals, which are stored in the magma chamber. They are perfect potential nucleation sites for bubbles. If there is no nucleation in the magma the bubbles formation might appear really late and magma becomes significantly supersaturated. The balance between supersaturation pressure and bubble's radii expressed by this equation: ∆P=2σ/r, where ∆P is 100 MPa and σ is the surface tension.
|
|
BSE-SEM image at 89 times magnification showing topsides of the calcite rafts (flat surfaces) and bottom crystals growing underneath Calcite crystals form on the surface of quiescent bodies of water, even when the bulk water is not supersaturated with respect to calcium carbonate. The crystals grow, attach to one other and appear to be floating rafts of a white, opaque material. The floating materials have been referred to as calcite rafts or "leopard spots".
|
|
These inferences are based on the assumption that accretion ice will have similar chemical signatures as the lake water that formed it. Scientists have thus far discovered diverse chemical conditions in subglacial lakes, ranging from upper lake layers supersaturated in oxygen to bottom layers that are anoxic and sulfur-rich. Despite their typically oligotrophic conditions, subglacial lakes and sediments are thought to contain regionally and globally significant amounts of nutrients, particularly carbon.
|
|
The amount of water that can exist as vapor in a given volume increases with the temperature. When the amount of water vapor is in equilibrium above a flat surface of water the level of vapor pressure is called saturation and the relative humidity is 100%. At this equilibrium there are equal numbers of molecules evaporating from the water as there are condensing back into the water. If the relative humidity becomes greater than 100%, it is called supersaturated.
|
|
A solution of a chemical compound in a liquid will become supersaturated when the temperature of the saturated solution is changed. In most cases solubility decreases with decreasing temperature; in such cases the excess of solute will rapidly separate from the solution as crystals or an amorphous powder. In a few cases the opposite effect occurs. The example of sodium sulphate in water is well-known and this was why it was used in early studies of solubility.
|
|
Anthropogenic cloud can be generated in laboratory or in situ to study its properties or use it for other purpose. A cloud chambers is a sealed environment containing a supersaturated vapor of water or alcohol. When a charged particle (for example, an alpha or beta particle) interacts with the mixture, the fluid is ionized. The resulting ions act as condensation nuclei, around which a mist will form (because the mixture is on the point of condensation).
|
|
The urea is added as a supersaturated aqueous solution to compensate for losses due to adduct formation during the process. In order to avoid a too high concentrations of adducts in the dewaxed oil a solvent such as methyl isobutyl ketone or methylene chloride is used for dilution. The ratio of oil to water phase is about 1 to 0.5. The mixing of the oil and water phases occurs at slightly elevated temperatures of about 35 °C.
|
|
Bubble formation can occur in the blood or other tissues. A solvent can carry a supersaturated load of gas in solution. Whether it will come out of solution in the bulk of the solvent to form bubbles will depend on a number of factors. Something which reduces surface tension, or adsorbs gas molecules, or locally reduces solubility of the gas, or causes a local reduction in static pressure in a fluid may result in a bubble nucleation or growth.
|
|
For pteropods to create shells they require aragonite which is produced through carbonate ions and dissolved calcium. Pteropods are severely affected because increasing acidification levels have steadily decreased the amount of water supersaturated with carbonate which is needed for aragonite creation. Arctic waters are changing so rapidly that they will become undersaturated with aragonite as early as 2016. Additionally the brittle star's eggs die within a few days when exposed to expected conditions resulting from Arctic acidification.
|
|
Ooids are most commonly composed of calcium carbonate (calcite or aragonite), but can be composed of phosphate, clays, chert, dolomite or iron minerals, including hematite. Dolomitic and chert ooids are most likely the result of the replacement of the original texture in limestone. Oolitic hematite occurs at Red Mountain near Birmingham, Alabama, along with oolitic limestone. They are usually formed in warm, supersaturated, shallow, highly agitated marine water intertidal environments, though some are formed in inland lakes.
|
|
During heating, the molecules increase in their translational mobility and therefore become liquid-like. Although it can be found that many hard candies are heated to about 310˚F, the temperature that the solution is heated to is dependent on the specific volume and contents of the mixture. After heating is complete, the solution can then be cooled. The final cooled solution is a supersaturated due to the fact that the moisture content drops to below 2%.
|
|
The composition of amorphous calcium phosphate is CaxHy(PO4)z·nH2O, where n is between 3 and 4.5. Precipitation from the moderately supersaturated and basic solution containing magnesium produces amorphous magnesium calcium phosphate (AMCP) in which magnesium incorporated into the ACP structure. A commercial preparation of ACP is casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), derived from cow milk. It is sold under various brand names including Recaldent and Tooth Mousse, intended to be applied directly on teeth.
|
|
Hydrothermal mineral deposits are accumulations of valuable minerals which formed from hot waters circulating in Earth's crust through fractures. They eventually create rich-metallic fluids concentrated in a selected volume of rock, which become supersaturated and then precipitate ore minerals. In some occurrences, minerals can be extracted at a profit by mining. Discovery of mineral deposits consumes considerable time and resources and only about one in every one thousand prospects explored by companies are eventually developed into a mine.
|
|
His invention of Nano-Pocket LEDs is the key architecture utilized in the efficient Gallium Nitride-based light emitting diodes. In the late 1970s Narayan pioneered in solute trapping of dopants in semiconductor materials with his discoveries of nanosecond laser annealing. This extensive solute trapping above the retrograde solubility limits resulted in formation of supersaturated semiconductor alloys used in current integrated circuits. This discovery resulted in him receiving US Department of Energy award in 1981 and IR-100 award in 1983.
|
|
Dendritic crystallization forms a natural fractal pattern. Dendritic crystals can grow into a supercooled pure liquid or form from growth instabilities that occur when the growth rate is limited by the rate of diffusion of solute atoms to the interface. In the latter case, there must be a concentration gradient from the supersaturated value in the solution to the concentration in equilibrium with the crystal at the surface. Any protuberance that develops is accompanied by a steeper concentration gradients at its tip.
|
|
The juices (containing 10-15 percent sucrose) are collected and mixed with lime to adjust pH to 7, prevent decay into glucose and fructose, and precipitate impurities. The lime and other suspended solids are settled out, and the clarified juice is concentrated in a multiple-effect evaporator to make a syrup with about 60 weight percent sucrose. The syrup is further concentrated under vacuum until it becomes supersaturated, and then seeded with crystalline sugar. Upon cooling, sugar crystallizes out of the syrup.
|
|
Islamic writers in the first half of the 9th century described the production of candy sugar, where crystals were grown through cooling supersaturated sugar solutions. According to the production process, rock sugar is divided into two types: single crystal rock sugar and polycrystalline rock sugar. According to Chinese tradition related in the "Tangshuangpu" (:zh:糖霜谱), a monk by the name of Wang Zhuo (王灼), from Suining in Sichuan, invented this method around 766–779 AD during the Tang Dynasty.
|
|
The arrival of the 808th Engineer Aviation Battalion permitted extensive rehabilitation work on Jackson. The runway had been sealed with an excess of bitumen, which became soft in the heat, and parked aircraft tended to sink into it. When the bitumen was removed to be re- laid, hydroscopic clay under parts of the runway became supersaturated through seepage, and springs developed. The engineers were forced to install underground drains, and put down a new base of crushed rock, which was sealed with bitumen.
|
|
During that time, he led the Chemical Department at King's College, and carried out many studies on crystallisation and supersaturated solutions. His other contributions were on the composition and properties of ancient glasses, the chemistry of pigments, putrefaction and antisepsis, the chemistry of building materials, and the composition and optical properties of double salts of nickel and cobalt. He co-edited several editions of Bloxam’s Chemistry, Inorganic and Organic. He was elected a Fellow of the Royal Society of Edinburgh in 1880.
|
|
ACC is the sixth and least stable polymorph of calcium carbonate. The remaining five polymorphs (in decreasing stability) are: calcite, aragonite, vaterite, monohydrocalcite and ikaite. When mixing two supersaturated solutions of calcium chloride and sodium carbonate (or sodium bicarbonates) these polymorphs will precipitate from solution following Ostwald's step rule, which states that the least stable polymorph will precipitate first. But while ACC is the first product to precipitate, it rapidly transforms into one of the more stable polymorphs within seconds.
|
|
Crystallization is triggered by flexing a small flat disc of notched ferrous metal embedded in the liquid. Pressing the disc releases very tiny adhered crystals of sodium acetate into the solution which then act as nucleation sites for the crystallization of the sodium acetate into the hydrated salt (sodium acetate trihydrate, CH3COONa·3H2O). Because the liquid is supersaturated, this makes the solution crystallize suddenly, thereby releasing the energy of the crystal lattice. The use of the metal disc was invented in 1978.
|
|
Crystallized honey: The inset shows a close-up of the honey, showing the individual glucose grains in the fructose mixture. The physical properties of honey vary, depending on water content, the type of flora used to produce it (pasturage), temperature, and the proportion of the specific sugars it contains. Fresh honey is a supersaturated liquid, containing more sugar than the water can typically dissolve at ambient temperatures. At room temperature, honey is a supercooled liquid, in which the glucose precipitates into solid granules.
|
|
Solubility of Na2SO4 in water as a function of temperature. Early studies of the phenomenon were conducted with sodium sulfate, also known as Glauber's Salt because, unusually, the solubility of this salt in water may decrease with increasing temperature. Early studies have been summarised by Tomlinson. It was shown that the crystallization of a supersaturated solution does not simply come from its agitation, (the previous belief) but from solid matter entering and acting as a “starting” site for crystals to form, now called "seeds".
|
|
Another process in common use is to rub a rod on the side of a glass vessel containing the solution to release microscopic glass particles which can act as nucleation centres. In industry, centrifugation is used to separate the crystals from the supernatant liquid. Some compounds and mixtures of compounds can form long-living supersaturated solutions. Carbohydrates are a class of such compounds; The thermodynamic barrier to formation of crystals is rather high because of extensive and irregular hydrogen bonding with the solvent, water.
|
|
She argued that only in public realm it is possible to fully express oneself. Hannah Arendt, The Human Condition (1958) Richard Sennett opposed what he saw as the Romantic idealization of the private realm of intimate relations, as opposed to the public sphere of action at a distance.Richard Sennett, The Fall of Public Man (1976) Deleuze and Guattari saw postmodernism as challenging the traditional split between private and public spheres, producing instead the supersaturated space of immediate presence and media- scrutiny of late capitalism.M. Hardt/K.
|
|
Deforming particles: Coherency hardening occurs when the interface between the particles and the matrix is coherent, which depends on parameters like particle size and the way that particles are introduced. Small particles precipitated from supersaturated solid solution usually have coherent interfaces with the matrix. Coherency hardening originates from the atomic volume difference between precipitate and the matrix, which results in a coherency strain. The associated stress field interacts with dislocations leading to an increase in yield strength, similar to the size effect in solid solution strengthening.
|
|
Panoramic view of travertine terraces at Pamukkale Pamukkale's terraces are made of travertine, a sedimentary rock deposited by mineral water from the hot springs. In this area, there are 17 hot springs with temperatures ranging from to . The water that emerges from the spring is transported to the head of the travertine terraces and deposits calcium carbonate on a section long covering an expanse of to . When the water, supersaturated with calcium carbonate, reaches the surface, carbon dioxide de-gasses from it, and calcium carbonate is deposited.
|
|
Traditional brown rock sugar White rock sugar Rock candy or sugar candy, also called rock sugar, or crystal sugar, is a type of confection composed of relatively large sugar crystals. This candy is formed by allowing a supersaturated solution of sugar and water to crystallize onto a surface suitable for crystal nucleation, such as a string, stick, or plain granulated sugar. Heating the water before adding the sugar allows more sugar to dissolve thus producing larger crystals. Crystals form after 6 to 7 days.
|
|
However, in many cases (e.g. passive drug transport) the driving force of passive transport can not be simplified to the concentration gradient. If there are different solutions at the two sides of the membrane with different equilibrium solubility of the drug, the difference in the degree of saturation is the driving force of passive membrane transport. It is also true for supersaturated solutions which are more and more important owing to the spreading of the application of amorphous solid dispersions for drug bioavailability enhancement.
|
|
Reusable heat pack containing supercooled solution and means for activating same. US Patent 4,077,390 (1978) The pad can be reused by placing it in boiling water for 10–15 minutes, which redissolves the sodium acetate trihydrate in the contained water and recreates a supersaturated solution. Once the pad has returned to room temperature it can be triggered again. Triggering the pad before it has reached room temperature results in the pad reaching a lower peak temperature, as compared to waiting until it had completely cooled.
|
|
The event resulted in the supersaturated deep water rapidly mixing with the upper layers of the lake, where the reduced pressure allowed the stored CO2 to effervesce out of solution. It is believed that about of gas was released. The normally blue waters of the lake turned a deep red after the outgassing, due to iron-rich water from the deep rising to the surface and being oxidised by the air. The level of the lake dropped by about a metre and trees near the lake were knocked down.
|
|
Expanding upon this, Gay-Lussac brought attention to the kinematics of salt ions and the characteristics of the container having an impact on the supersaturation state. He was also able to expand upon the number of salts with which a supersaturated solution can be obtained. Later Henri Löwel came to the conclusion that both nuclei of the solution and the walls of the container have a catalyzing effect on the solution that cause crystallization. Explaining and providing a model for this phenomenon has been a task taken on by more recent research.
|
|
Like Gaye and Hathaway, Rux creates supersaturated, open-ended soul music that can tend toward the programmatic, with bluesy vamps, touches of minimalism, and slide- guitar licks providing a rich backdrop for his sardonic baritone. On Behind The Curtain, Rux achieves a pop-gospel synthesis that recalls the work of Loves Arthur Lee. Black Of The Shadow features Brazilian guitarist Vinicius Cantuaria, while All The Rock Stars is a series of funk grooves that add up to an ingeniously dovetailed mutant samba. Rux sings with a sense of outrage, delivered with real passion.
|
|
The combined concentrations of gases in any given tissue depend on the history of pressure and gas composition. Under equilibrium conditions, the total concentration of dissolved gases is less than the ambient pressure—as oxygen is metabolised in the tissues, and the carbon dioxide produced is much more soluble. However, during a reduction in ambient pressure, the rate of pressure reduction may exceed the rate at which gas is eliminated by diffusion and perfusion. If the concentration gets too high, it may reach a stage where bubble formation can occur in the supersaturated tissues.
|
|
If the air parcel is lifting further beyond the LCL, water vapor in the air parcel will begin condensing, forming cloud droplets. (In the real atmosphere, it is usually necessary for air to be slightly supersaturated, normally by around 0.5%, before condensation occurs; this translates into about 10 meters or so of additional lifting above the LCL.) The LCL is a good approximation of the height of the cloud base which will be observed on days when air is lifted mechanically from the surface to the cloud base (e.g., due to convergence of airmasses).
|
|
It has been hypothesised that the series of shallow dives and the long periods between foraging dives are needed to recover from the oxygen debt in preparation for the next deep dive. The long intervals spent near the surface are considered to be inconsistent with the hypothesis that beaked whales are chronically supersaturated at high levels. The similar times of descent and ascent of the shallow post-foraging dives do not appear to be consistent with requirements for recompression. The relatively slow ascents from foraging dives are not adequately explained.
|
|
Rode and his coworkers discovered the salt induced peptide formation reaction as a simple route to synthesis peptides from amino acid monomers under prebiotic conditions. Instead of enzymes transition metals act as catalyst to induce peptide formation in highly concentrated aqueous NaCl solution, with copper (II) showing the highest catalytic activity. Typically, evaporation cycle experiments have been carried out to mimic day/night cycles on shore and in lagoons, thereby generating supersaturated solutions. Since such solutions have a tendency to dilute themselves, the thermodynamic and kinetic unfavourable peptide formation reaction is promoted.
|
|
The first is nucleation, the appearance of a crystalline phase from either a supercooled liquid or a supersaturated solvent. The second step is known as crystal growth, which is the increase in the size of particles and leads to a crystal state. An important feature of this step is that loose particles form layers at the crystal's surface and lodge themselves into open inconsistencies such as pores, cracks, etc. The majority of minerals and organic molecules crystallize easily, and the resulting crystals are generally of good quality, i.e.
|
|
In the process of protein crystallization, proteins are dissolved in an aqueous environment and sample solution until they reach the supersaturated state. Different methods are used to reach that state such as vapor diffusion, microbatch, microdialysis, and free-interface diffusion. Developing protein crystals is a difficult process influenced by many factors, including pH, temperature, ionic strength in the crystallization solution, and even gravity. Once formed, these crystals can be used in structural biology to study the molecular structure of the protein, particularly for various industrial or medical purposes.
|
|
Whatever the cause, the event resulted in the rapid mixing of the supersaturated deep water with the upper layers of the lake, where the reduced pressure allowed the stored to effervesce out of solution. It is believed that about of gas was released. The normally blue waters of the lake turned a deep red after the outgassing, due to iron-rich water from the deep rising to the surface and being oxidised by the air. The level of the lake dropped by about a metre and trees near the lake were knocked down.
|
|
Tartrates separate from new wines because they are less soluble in alcohol than in non-alcoholic grape juice. The exact figures vary according to variety and region, but approximately half of the tartrate soluble in grape juice is insoluble in wine. The problem is that the tartrate may remain in a supersaturated state after bottling, only to crystallize at some unpredictable later time. Tartrates precipitated in red wine usually take on some red pigment and are commonly dismissed as mere sediment; in white wines they can look alarmingly like shards of glass.
|
|
Honeys that are supersaturated with a very high percentage of glucose, such as brassica honey, crystallize almost immediately after harvesting, while honeys with a low percentage of glucose, such as chestnut or tupelo honey, do not crystallize. Some types of honey may produce few but very large crystals, while others produce many small crystals.Tomasik, Piotr (2004) Chemical and functional properties of food saccharides, CRC Press, p. 74, Crystallization is also affected by water content, because a high percentage of water inhibits crystallization, as does a high dextrin content.
|
|
The primary mechanism for the formation of ice clouds was discovered by Tor Bergeron. The Bergeron process notes that the saturation vapor pressure of water, or how much water vapor a given volume can contain, depends on what the vapor is interacting with. Specifically, the saturation vapor pressure with respect to ice is lower than the saturation vapor pressure with respect to water. Water vapor interacting with a water droplet may be saturated, at 100% relative humidity, when interacting with a water droplet, but the same amount of water vapor would be supersaturated when interacting with an ice particle.
|
|
However, some recycled carbon–magnesite brick is used as the basis for furnace-repair materials, and also crushed carbon–magnesite brick is used in slag conditioners. While crucibles have a high graphite content, the volume of crucibles used and then recycled is very small. A high-quality flake graphite product that closely resembles natural flake graphite can be made from steelmaking kish. Kish is a large-volume near-molten waste skimmed from the molten iron feed to a basic oxygen furnace, and consists of a mix of graphite (precipitated out of the supersaturated iron), lime-rich slag, and some iron.
|
|
Cooling can cause phase separation and mineral deposition, accompanied by a shift toward more reducing conditions. At the surface expression of such hydrothermal systems, low-temperature volcanic gases (<400 °C) are either emanating as steam-gas mixtures or in dissolved form in hot springs. At the ocean floor, such hot supersaturated hydrothermal fluids form gigantic chimney structures called black smokers, at the point of emission into the cold seawater. Over geological time, this process of hydrothermal leaching, alteration, and/or redeposition of minerals in the country rock is an effective process of concentration that generates certain types of economically valuable ore deposits.
|
|
To overcome the limitations of solution saturation and to use natural comminution of sand particles from wave energy, silicate minerals may be applied to coastal environments, although the higher pH of seawater may substantially decrease the rate of dissolution, and it is unclear how much comminution is possible from wave action. Alternatively, the direct application of carbonate minerals to the up-welling regions of the ocean has been investigated. Carbonate minerals are supersaturated in the surface ocean but are undersaturated in the deep ocean. In areas of up welling this undersaturated water is brought to the surface.
|
|
The Mason equation is an approximate analytical expression for the growth (due to condensation) or evaporation of a water droplet--it is due to the meteorologist B. J. Mason.1\. B. J. Mason The Physics of Clouds (1957) Oxford Univ. Press. The expression is found by recognising that mass diffusion towards the water drop in a supersaturated environment transports energy as latent heat, and this has to be balanced by the diffusion of sensible heat back across the boundary layer, (and the energy of heatup of the drop, but for a cloud-sized drop this last term is usually small).
|
|
According to monitoring carried out in 2003/2004 by Shakhova et al., the surface layer of shelf water in the East Siberian Sea and Laptev Sea was supersaturated up to 2500% relative to then present average atmospheric methane content of 1.85 ppm. Anomalously high concentrations (up to 154 nM or 4400% supersaturation) of dissolved methane in the bottom layer of shelf water suggest that the bottom layer is somehow affected by near- bottom sources. Considering the possible formation mechanisms of such plumes, their studies indicated thermoabrasion and the effects of shallow gas or gas hydrates release.
|
|
When the water, supersaturated with calcium carbonate and iron carbonate, reaches the surface, carbon dioxide degases from it, and mineral carbonates are deposited. The depositing continues until the carbon dioxide in the water balances the carbon dioxide in the air. Iron carbonate and calcium carbonate are deposited by the water as soft jellies, but they eventually harden into travertine. As a result, over the course of thousands of years the water from these two springs emanating from the mountain range have combined and resulted in a number of orange-, red- and yellow-colored pools shaped as a naturally formed staircase.
|
|
A sodium acetate heat pad Disposable chemical pads employ a one-time exothermic chemical reaction. One type, frequently used for hand warmers, is triggered by unwrapping an air-tight packet containing slightly moist iron powder and salt or catalysts which rusts over a period of hours after being exposed to oxygen in the air. Another type contains separate compartments within the pad; when the user squeezes the pad, a barrier ruptures and the compartments mix, producing heat such as the enthalpy change of solution of calcium chloride dissolving. The most common reusable heat pads contain a supersaturated solution of sodium acetate in water.
|
|
If the ionic compound is soluble in a solvent, it can be obtained as a solid compound by evaporating the solvent from this electrolyte solution. As the solvent is evaporated, the ions do not go into the vapour, but stay in the remaining solution, and when they become sufficiently concentrated, nucleation occurs, and they crystallize into an ionic compound. This process occurs widely in nature, and is the means of formation of the evaporite minerals. Another method of recovering the compound from solution involves saturating a solution at high temperature and then reducing the solubility by reducing the temperature until the solution is supersaturated and the solid compound nucleates.
|
|
Scanning electron microscope image of rime frost on both ends of a "capped column" snowflake. Once a droplet has frozen, it grows in the supersaturated environment, which is one where air is saturated with respect to ice when the temperature is below the freezing point. The droplet then grows by deposition of water molecules in the air (vapor) onto the ice crystal surface where they are collected. Because water droplets are so much more numerous than the ice crystals due to their sheer abundance, the crystals are able to grow to hundreds of micrometers or millimeters in size at the expense of the water droplets.
|
|
With the discovery of nanosecond laser annealing, Narayan has pioneered developments in laser- solid interactions and transient thermal processing of nanomaterials and epitaxial thin films. With the development of pulsed laser deposition technique and domain matching epitaxy paradigm, he formed relaxed stoichiometric thin films on industrially relevant substrates across the misfit scale. These developments in materials fabrication technology resulted in fabrication of novel multifunctional materials like supersaturated semiconductor alloys, metal-ceramic nanocomposites, and laser-diffused solar cells. While working on laser annealing of semiconductor alloys, Narayan touted it as the technique of choice for achieving temporal and spatial control on the dopant concentration in doped semiconductors.
|
|
Metatorbernite (or meta-torbernite) is a radioactive phosphate mineral, and is a dehydration pseudomorph of torbernite. Chemically, it is a copper uranyl phosphate and usually occurs in the form of green platy deposits. It can form by direct deposition from a supersaturated solution, which produces true crystalline metatorbernite, with a dark green colour, translucent diaphaneity, and vitreous lustre. However, more commonly, it is formed by the dehydration of torbernite, which causes internal stress and breakage within the crystal lattice, resulting in crystals composed of microscopic powder held together using electrostatic force, and having a lighter green colour, opaque diaphaneity, and a relatively dull lustre.
|
|
Bubble models for decompression were popular among technical divers in the early 2000s, although there was little data to support the effectiveness of the models in practice. Since then, several comparative studies have indicated relatively larger numbers of venous gas emboli after decompression based on bubble models, and one study reported a higher rate of decompression sickness. The deeper decompression stops earlier in the ascent appear to be less effective at controlling bubble formation than the hypotheses suggested. This failure may be due to continued ingassing of slower tissues during the extended time at greater depth, resulting in these tissues being more supersaturated at shallower depths.
|
|
Jolly Ranchers are manufactured by creating a solution of corn syrup, sucrose, glucose, or fructose syrup that is boiled to a temperature of 160 °C/320F and cooled to create a supersaturated mixture that is roughly 2.5 percent water. As the mixture is cooled, natural and artificial flavoring and artificial colors (red 40, blue 1, yellow 5, yellow 6) are added to individual batches of syrup solution which are later mixed with malic acid to improve shelf life and add further flavor. Once the mixture begins to cool it is then extruded into long malleable strings that are cut to size and individually wrapped and packaged.
|
|
It is agreed among local residents and pond workers that the cooperative system was established during the time of the Incas, if not earlier. As water evaporates from the sun-warmed ponds, the water becomes supersaturated and salt precipitates as various size crystals onto the inner surfaces of a pond's earthen walls and on the pond's earthen floor. The pond's keeper then closes the water-feeder notch and allows the pond to go dry. Within a few days the keeper carefully scrapes the dry salt from the sides and bottom, puts it into a suitable vessel, reopens the water-supply notch, and carries away the salt.
|
|
It is then in a metastable state, and we may expect condensation to take place. A reasonable molecular model of condensation would seem to be that two or three molecules of water vapour come together to form a tiny droplet, and that this nucleus of condensation then grows by accretion, as additional vapour molecules happen to hit it. The Kelvin equation, however, indicates that a tiny droplet like this nucleus, being only a few ångströms in diameter, would have a vapour pressure many times that of the bulk liquid. As far as tiny nuclei are concerned, the vapour would not be supersaturated at all.
|
|
Steps of 321x321px X-ray crystallography is one of the more efficient and important methods for attempting to decipher the three dimensional configuration of a folded protein. To be able to conduct X-ray crystallography, the protein under investigation must be located inside a crystal lattice. To place a protein inside a crystal lattice, one must have a suitable solvent for crystallization, obtain a pure protein at supersaturated levels in solution, and precipitate the crystals in solution. Once a protein is crystallized, x-ray beams can be concentrated through the crystal lattice which would diffract the beams or shoot them outwards in various directions.
|
|
Dissolved oxygen levels required by various species in the Chesapeake Bay (US) In aquatic environments, oxygen saturation is a ratio of the concentration of dissolved oxygen (O2), to the maximum amount of oxygen that will dissolve in that water body, at the temperature and pressure which constitute stable equilibrium conditions. Well- aerated water (such as a fast-moving stream) without oxygen producers or consumers is 100% saturated. It is possible for stagnant water to become somewhat supersaturated with oxygen (i.e. reach more than 100% saturation) either because of the presence of photosynthetic aquatic oxygen producers or because of a slow equilibration after a change of atmospheric conditions.
|
|
However, the CNT fails in describing experimental results of vapour to liquid nucleation even for model substances like argon by several orders of magnitude.A. Fladerer, R. Strey: „Homogeneous nucleation and droplet growth in supersaturated argon vapor: The cryogenic nucleation pulse chamber.“ in: The Journal of Chemical Physics 124(16), 164710 (2006). (Online) For nucleation of a new thermodynamic phase, such as the formation of ice in water below 0°C, if the system is not evolving with time and nucleation occurs in one step, then the probability that nucleation has not occurred should undergo exponential decay. This is seen for example in the nucleation of ice in supercooled small water droplets.
|
|
Calcite rafts in Kartchner Caverns, Arizona Calcium carbonate is known to precipitate as calcite crystals in water supersaturated with calcium and carbonate ions. Under quiescent conditions, calcite crystals can form on a water surface when calcium carbonate supersaturation conditions do not exist in the bulk water. Water evaporates from the surface and carbon dioxide degasses from the surface layer to create a thin layer of water with high pH and concentrations of calcium and carbonate ions far above the saturation concentration for calcium carbonate. Calcite crystals precipitate in this highly localized environment and attach to one another to form what appear to be rafts of a white material.
|
|
Example of secondary efflorescence in parking garage exposed to diluted road salt from vehicles entering the garage during winter. When water flows through cracks present in concrete, water may dissolve various minerals present in the hardened cement paste or in the aggregates, if the solution is unsaturated with respect to them. Dissolved ions, such as calcium (Ca2+), are leached out and transported in solution some distance. If the physico-chemical conditions prevailing in the seeping water evolve with distance along the water path and water becomes supersaturated with respect to certain minerals, they can further precipitate, making calthemite deposits (predominately calcium carbonate) inside the cracks, or at the concrete outer surface.
|
|
Decompression (altitude) refers to the reduction in ambient pressure due to ascent above sea level. Decompression has physical effects on gas filled spaces and on liquids, particularly when they contain dissolved gases. Physiological effects of decompression are due to these physical effects and the consequential effects on the living tissues, mostly as a result of the formation and growth of bubbles, and the expansion of gas filled spaces. Formation and growth of bubbles due to reduced pressure can be due to reduction in solubility as described by Henry's Law, nucleation and growth of bubbles in supersaturated liquids and boiling of liquids when the pressure is reduced below the vapour pressure for the temperature of the liquid.
|
|
Water vapor in saturated air is normally attracted to condensation nuclei such as salt particles that are small enough to be held aloft by normal circulation of the air. If the condensation process occurs below the freezing level in the troposphere, the nuclei help transform the vapor into very small water droplets. Clouds that form just above the freezing level are composed mostly of supercooled liquid droplets, while those that condense out at higher altitudes where the air is much colder generally take the form of ice crystals. An absence of sufficient condensation particles at and above the condensation level causes the rising air to become supersaturated and the formation of cloud tends to be inhibited.
|
|
" Uncut also gave a positive review of the album, stating in their April 2014 issue that "the sound they've fashioned is glossy and supersaturated while still exhibiting the subversive impulse that yielded the supremely catchy but subtly sinister smash 'Pumped Up Kicks'". Melanie Haupt of The Austin Chronicle stated that the band, "working on an epic, operatic canvas, hide the spinach of existential angst into sweetly binge- worthy dance pop". John Aizlewood, writing for Q, opined that the "occasionally super Supermodel is an album of transition rather than a definitive statement". PopMatters writer Jeff Koch opined that the record was "startlingly different from Torches" and a "massive surprise", but nonetheless "achingly, devastatingly beautiful.
|
|
Therefore, this type of metabolism mainly occurs in anoxic sites, such as lake sediments, deep-sea hydrothermal vents and human gut. Probably mainly due to the biotic processes, in the marine habitats it was observed that the concentrations of hydrogen were supersaturated. In all these environments, the highest concentrations were in the first metres, decreasing to the thermocline and reaching the lowest concentrations in the deep oceans. Globally, tropical and subtropical oceans appear to have the most abundant quantity of H2, while the least amount is present in higher latitudes However, it was observed that the release of hydrogen in the oceans is dependent on the solar radiation, showing a daily change with the maximum peak at noon.
|
|
Injury by bubble formation and growth in body tissues is the mechanism of decompression sickness, which occurs when supersaturated dissolved inert gases leave solution as bubbles during decompression. The damage can be due to mechanical deformation of tissues due to bubble growth in situ, or by blocking blood vessels where the bubble has lodged. Arterial gas embolism can occur when a gas bubble is introduced to the circulatory system and it lodges in a blood vessel which is too small for it to pass through under the available pressure difference. This can occur as a result of decompression after hyperbaric exposure, a lung overexpansion injury, during intravenous fluid administration, or during surgery.
|
|
Crystal formation can be divided into two types, where the first type of crystals are composed of a cation and anion, also known as a salt, such as sodium acetate. The second type of crystals are composed of uncharged species, for example menthol. Crystal formation can be achieved by various methods, such as: cooling, evaporation, addition of a second solvent to reduce the solubility of the solute (technique known as antisolvent or drown-out), solvent layering, sublimation, changing the cation or anion, as well as other methods. The formation of a supersaturated solution does not guarantee crystal formation, and often a seed crystal or scratching the glass is required to form nucleation sites.
|
|
When hydrogen moves out of solution with iron it reverts to elemental hydrogen (). When iron hydrides with more than 2 ppm hydrogen are cooled, the hydrogen no longer fits within the crystalline structures, resulting in an excess of hydrogen. The way for hydrogen to leave the crystalline phases is for it to precipitate out of solution as elemental hydrogen, leaving behind a surrounding phase of BCC iron called ferrite with a small proportion of hydrogen in solution. In a supersaturated composition (greater than 2 ppm hydrogen), the hydrogen will precipitate out as large inclusions of elemental hydrogen at the grain boundaries until the proportion of hydrogen in the grains has decreased to the saturated composition (2 ppm).
|
|
The above assumes that the cooling process is very slow, allowing enough time for the hydrogen to migrate. As the rate of cooling is increased, the hydrogen will have less time to migrate to form elemental hydrogen at the grain boundaries; hence the elemental hydrogen is more widely dispersed and acts to prevent slip of defects within those grains, resulting in hardening of the iron hydride. At the very high cooling rates produced by quenching, the hydrogen has no time to migrate but is locked within the crystalline structure and forms martensic iron hydride. Martensic iron hydride is a highly strained and stressed, supersaturated form of hydrogen and iron and is exceedingly hard but brittle.
|
|
Sinclair Canyon The geology of the park is dominated by mountains made up of exposed faulted sedimentary rock and valleys containing glacial till deposited in the Pleistocene. Just outside the northwestern corner of the park, there is an igneous intrusion known as the Ice River Complex containing deposits of sodalite, an ornamental stone. The hills immediately around the hot springs are composed mainly of tufa, a calcium carbonate deposit that forms by precipitation of supersaturated hot spring water when it reaches cooler surface water. The rocks in southwestern corner of the park are part of the older Purcell Mountains range while the eastern park mountains are part of the younger Rocky Mountains range.
|
|
As their categorical name suggests, extended chords indeed extend seventh chords by stacking one or more additional third-intervals, successively constructing ninth, eleventh, and finally thirteenth chords; thirteenth chords contain all seven notes of the diatonic scale. In closed position, extended chords contain dissonant intervals or may sound supersaturated, particularly thirteenth chords with their seven notes. Consequently, extended chords are often played with the omission of one or more tones, especially the fifth and often the third, as already noted for seventh chords; similarly, eleventh chords often omit the ninth, and thirteenth chords the ninth or eleventh. Often, the third is raised an octave, mimicking its position in the root's sequence of harmonics.
|
|
The coldest naturally occurring temperature ever observed on Earth, , was recorded at Vostok Station on 21 July 1983. The average water temperature is calculated to be around ; it remains liquid below the normal freezing point because of high pressure from the weight of the ice above it. Geothermal heat from the Earth's interior may warm the bottom of the lake, while the ice sheet itself insulates the lake from cold temperatures on the surface. Lake Vostok is an oligotrophic extreme environment, one that is expected to be supersaturated with nitrogen and oxygen, measuring of nitrogen and oxygen per of water, that is 50 times higher than those typically found in ordinary freshwater lakes on Earth's surface.
|
|
These features of the rootlets suggest that they are homologous to the aerial leaves of Lepidodendrales but modified to serve anchoring and absorbing functions. This implies that the underground organs of the plants arose as evolutionary modification of the aerial organs. Stigmaria with rootlets Despite the towering height of some Lepidodendrales plants, their stigmarian system was typically shallow, and therefore it is dubious how the underground organs could support the huge trees, especially since many plants grew in supersaturated, watery soil that was largely unstable. Different suggestions have arisen to explain their stature and root system: it may be that the extensive horizontal growth of the root axes provided enough support, or that the crowns of adjacent trees could entangle and provide mutual support.
|
|
Good Bread Alley is the third studio album of Carl Hancock Rux. Titled after a close-knit historically African American district of shotgun houses that once occupied a segregated neighborhood in Miami, Florida, the cd was released by Thirsty Ear Music, produced by Carl Hancock Rux with songwriting and co- songwriting credits from Geoff Barrow, Vinicius Cantuária, David Holmes, Rob Hyman, Stewart Lerman, Darren Morris, Phil Mossman, Vernon Reid, Tim Saul, Jaco Van Schalkwyk, and Bill Withers. The cd tackles religion, sexual politics, war and media overload, in the tradition of Marvin Gaye and Donny Hathaway, employing supersaturated, open-ended soul music with bluesy vamps, touches of minimalism, and slide-guitar licks providing a rich backdrop for Rux's sardonic baritone, achieving a pop-gospel synthesis.
|
|
5-10% of all racemates are known to crystallize as mixtures of enantiopure crystals, so-called conglomerates.Enantiomers, racemates, and resolutions Jean Jacques, André Collet, Samuel H Wilen 1981 Louis Pasteur was the first to conduct chiral resolution when he discovered the concept of optical activity by the manual separation of left-handed and right-handed sodium ammonium tartrate crystals in 1849. In 1882 he went on to demonstrate that by seeding a supersaturated solution of sodium ammonium tartrate with a d-crystal on one side of the reactor and a l-crystal on the opposite side, crystals of opposite handedness will form on the opposite sides of the reactor. This type of resolution, called spontaneous resolution, has also been demonstrated with racemic methadone.
|
|
Martensite is formed in carbon steels by the rapid cooling (quenching) of the austenite form of iron at such a high rate that carbon atoms do not have time to diffuse out of the crystal structure in large enough quantities to form cementite (Fe3C). Austenite is gamma-phase iron (γ-Fe), a solid solution of iron and alloying elements. As a result of the quenching, the face-centered cubic austenite transforms to a highly strained body- centered tetragonal form called martensite that is supersaturated with carbon. The shear deformations that result produce a large number of dislocations, which is a primary strengthening mechanism of steels. The highest hardness of a pearlitic steel is 400 Brinell, whereas martensite can achieve 700 Brinell.
|
|
Under equilibrium conditions, the total concentration of dissolved gases will be less than the ambient pressure, as oxygen is metabolised in the tissues, and the carbon dioxide produced is much more soluble. However, during a reduction in ambient pressure, the rate of pressure reduction may exceed the rate at which gas can be eliminated by diffusion and perfusion, and if the concentration gets too high, it may reach a stage where bubble formation can occur in the supersaturated tissues. When the pressure of gases in a bubble exceed the combined external pressures of ambient pressure and the surface tension from the bubble - liquid interface, the bubbles will grow, and this growth can cause damage to tissues. Symptoms caused by this damage are known as Decompression sickness.
|
|
When the urine becomes supersaturated (when the urine solvent contains more solutes than it can hold in solution) with one or more calculogenic (crystal-forming) substances, a seed crystal may form through the process of nucleation. Heterogeneous nucleation (where there is a solid surface present on which a crystal can grow) proceeds more rapidly than homogeneous nucleation (where a crystal must grow in a liquid medium with no such surface), because it requires less energy. Adhering to cells on the surface of a renal papilla, a seed crystal can grow and aggregate into an organized mass. Depending on the chemical composition of the crystal, the stone-forming process may proceed more rapidly when the urine pH is unusually high or low.
|
|
This is known as outgassing, and occurs during decompression, when the reduction in ambient pressure or a change of breathing gas reduces the partial pressure of the inert gas in the lungs. The combined concentrations of gases in any given tissue will depend on the history of pressure and gas composition. Under equilibrium conditions, the total concentration of dissolved gases will be less than the ambient pressure, as oxygen is metabolised in the tissues, and the carbon dioxide produced is much more soluble. However, during a reduction in ambient pressure, the rate of pressure reduction may exceed the rate at which gas can be eliminated by diffusion and perfusion, and if the concentration gets too high, it may reach a stage where bubble formation can occur in the supersaturated tissues.
|
|
In general, frost flowers only form in relatively windless conditions; in high winds the supersaturated layer is scrubbed from the surface and blowing snow obscures the ice surface.. Frost flowers can grow and spread forming a dense concentration of frost flowers across the ocean. On lake ice, frost flowers are effectively identical to hoar frost crystals. On sea ice, through surface tension and differences in concentration gradients, frost flowers that sit on brine-saturated surfaces wicks up the brine, increasing the bulk salinity, which leads to high salinity. The tips of mature frost flowers are less saline due to vapor deposition and the bulk salinity decreases at night due to hoarfrost accumulation as the temperature drops and snow (they are very good at collecting snow) which also reduces their bulk salinity over time.
|
|
This syrup is further concentrated under vacuum in a vacuum boiling pan until it becomes supersaturated, finely ground sugar crystals suspended in alcohol are introduced into the vacuum pan as seed crystals around which sucrose is deposited and these crystals then grow in size until they are ready to be discharged (typically about ) A number of boiling schemes are possible, the most commonly used boiling scheme is the three-boiling scheme. This method boils the sugar liquors in three stages, called A-, B- and C-. A batch type sugar centrifuge separates the sugar crystals from the mother liquor. These centrifuges have a capacity of up to per cycle. The sugar from the centrifuges is dried and cooled and then stored in a silo or directly packed into bags for shipment.
|
|
The accumulation of ions is driven by ion pumps packed within the calcifying epithelium. Calcium ions are obtained from the organism's environment through the gills, gut and epithelium, transported by the haemolymph ("blood") to the calcifying epithelium, and stored as granules within or in-between cells ready to be dissolved and pumped into the extrapallial space when they are required. The organic matrix forms the scaffold that directs crystallization, and the deposition and rate of crystals is also controlled by hormones produced by the mollusc. Because the extrapallial space is supersaturated, the matrix could be thought of as impeding, rather than encouraging, carbonate deposition; although it does act as a nucleating point for the crystals and controls their shape, orientation and polymorph, it also terminates their growth once they reach the necessary size.
|
|
The combined concentrations of gases in any given tissue will depend on the history of pressure and gas composition. Under equilibrium conditions, the total concentration of dissolved gases will be less than the ambient pressure, as oxygen is metabolised in the tissues, and the carbon dioxide produced is much more soluble. However, during a reduction in ambient pressure, the rate of pressure reduction may exceed the rate at which gas can be eliminated by diffusion and perfusion, and if the concentration gets too high, it may reach a stage where bubble formation can occur in the supersaturated tissues. When the pressure of gases in a bubble exceed the combined external pressures of ambient pressure and the surface tension from the bubble - liquid interface, the bubbles will grow, and this growth can cause damage to tissues.
|
|
Mechanical alloying (MA) is a solid-state and powder processing technique involving repeated cold welding, fracturing, and re-welding of blended powder particles in a high-energy ball mill to produce a homogeneous material. Originally developed to produce oxide-dispersion strengthened (ODS) nickel- and iron-base superalloys for applications in the aerospace industry,H. K. D. H. Bhadeshia, Practical ODS Alloys, Materials Science and Engineering A, 223 (1997)64-77 MA has now been shown to be capable of synthesizing a variety of equilibrium and non-equilibrium alloy phases starting from blended elemental or pre-alloyed powders.Suryanarayana C. Mechanical alloying and milling, Progress in Materials Science 46 (2001) 1-184 The non-equilibrium phases synthesized include supersaturated solid solutions, metastable crystalline and quasicrystalline phases, nanostructures, and amorphous alloys.
|
|
Some small Archean evaporite deposits require that at least locally elevated concentrations (possibly due to local volcanic activity) of sulfate existed in order for them to be supersaturated and precipitate out of solution. 3.8–3.6 Ga marks the beginning of the exposed geologic record because this is the age of the oldest rocks on Earth. Metasedimentary rocks from this time still have an isotopic value of 0 because the biosphere was not developed enough (possibly at all) to fractionate sulfur. 3.5 Ga anoxyogenic photosynthesis is established and provides a weak source of sulfate to the global ocean with sulfate concentrations incredibly low the δ34S is still basically 0. Shortly after, at 3.4 Ga the first evidence for minimal fractionation in evaporitic sulfate in association with magmatically derived sulfides can be seen in the rock record.
|
|
When the Shpolskii effect is manifested, the solid state solubility increases two to three orders of magnitude.L. A. Nakhimovsky, M. Lamotte, J. Joussot-dubien, Handbook of Low Temperature Electronic Spectra of Polycyclic Aromatic Hydrocarbons, Chapter II, Elsevier, 1989 Isothermic annealing of the supersaturated rapidly frozen solutions of dibenzofuran in heptane was performed, and it was shown that the return of the metastable system to equilibrium in time reasonable for laboratory observation required the annealing temperature to be close to the melting temperature of the metastable frozen solution. Thus the Shpolskii systems are an example of a persistent metastable state. A good match between the chromophore and the host lattice leads to a uniform environment for all the chromophores and hence greatly reduces the inhomogeneous broadening of the electronic transition's pure electronic and vibronic lines.
|
|
These bubble nuclei are spherical gas phases that are small enough to remain in suspension yet strong enough to resist collapse, their stability being provided by an elastic surface layer consisting of surface-active molecules which resists the effect of surface tension. Once a micro-bubble forms it may continue to grow if the tissues are sufficiently supersaturated. As the bubble grows it may distort the surrounding tissue and cause damage to cells and pressure on nerves resulting in pain, or may block a blood vessel, cutting off blood flow and causing hypoxia in the tissues normally perfused by the vessel. If a bubble or an object exists which collects gas molecules this collection of gas molecules may reach a size where the internal pressure exceeds the combined surface tension and external pressure and the bubble will grow.
|
|
As the shells dissolve, the organisms struggle to maintain proper health, which can lead to mass mortality. The loss of many of these species can lead to intense consequences on the marine food web in the Arctic Ocean, as many of these marine calcifying organisms are keystone species. Laboratory experiments on various marine biota in an elevated CO₂ environment show that changes in aragonite saturation cause substantial changes in overall calcification rates for many species of marine organisms, including coccolithophore, foraminifera, pteropods, mussels, and clams. Although the undersaturation of arctic water has been proven to have an effect on the ability of organisms to precipitate their shells, recent studies have shown that the calcification rate of calcifiers, such as corals, coccolithophores, foraminiferans and bivalves, decrease with increasing pCO₂, even in seawater supersaturated with respect to CaCO₃.
|
|
An equation similar to that of Kelvin can be derived for the solubility of small particles or droplets in a liquid, by means of the connection between vapour pressure and solubility, thus the Kelvin equation also applies to solids, to slightly soluble liquids, and their solutions if the partial pressure p is replaced by the solubility of the solid (or a second liquid) at the given radius, r, and p_0 by the solubility at a plane surface. Hence small particles (like small droplets) are more soluble than larger ones. These results led to the problem of how new phases can ever arise from old ones. For example, if a container filled with water vapour at slightly below the saturation pressure is suddenly cooled, perhaps by adiabatic expansion, as in a cloud chamber, the vapour may become supersaturated with respect to liquid water.
|
|
Most industrial crystallizers are of the evaporative type, such as the very large sodium chloride and sucrose units, whose production accounts for more than 50% of the total world production of crystals. The most common type is the forced circulation (FC) model (see evaporator). A pumping device (a pump or an axial flow mixer) keeps the crystal slurry in homogeneous suspension throughout the tank, including the exchange surfaces; by controlling pump flow, control of the contact time of the crystal mass with the supersaturated solution is achieved, together with reasonable velocities at the exchange surfaces. The Oslo, mentioned above, is a refining of the evaporative forced circulation crystallizer, now equipped with a large crystals settling zone to increase the retention time (usually low in the FC) and to roughly separate heavy slurry zones from clear liquid.
|
|
The various conditions can use one or more physical mechanisms to lower the solubility of the molecule; for example, some may change the pH, some contain salts of the Hofmeister series or chemicals that lower the dielectric constant of the solution, and still others contain large polymers such as polyethylene glycol that drive the molecule out of solution by entropic effects. It is also common to try several temperatures for encouraging crystallization, or to gradually lower the temperature so that the solution becomes supersaturated. These methods require large amounts of the target molecule, as they use high concentration of the molecule(s) to be crystallized. Due to the difficulty in obtaining such large quantities (milligrams) of crystallization-grade protein, robots have been developed that are capable of accurately dispensing crystallization trial drops that are in the order of 100 nanoliters in volume.
|
|
The values for K1 and K2 can be influenced by several different physical factors, including temperature, salinity and pressure, so organisms in different habitats can encounter different equilibrium conditions. Many of these same factors influence solubility of calcium carbonate, with the solubility product constant Ksp expressed as the concentration of dissolved calcium and carbonate ions at equilibrium: Ksp = [Ca2+][CO32−]. Therefore, increases in Ksp based on differences in temperature or pressure or increases in the apparent solubility constant K’sp as a result of salinity or pH changes means that calcium carbonate is more soluble. Increased solubility of CaCO3 makes shell deposition more difficult, and so this has a negative impact on the calcification process. The saturation state of calcium carbonate also has a strong influence on shell deposition, with calcification only occurring when the water is saturated or supersaturated with CaCO3, based on the formula: Ω = [CO32−][Ca2+] / K’sp.
|
|
If the solvent outside the bubble is saturated or unsaturated, the partial pressure will be less than in the bubble, and the surface tension will be increasing the internal pressure in direct proportion to surface curvature, providing a pressure gradient to increase diffusion out of the bubble, effectively "squeezing the gas out of the bubble", and the smaller the bubble the faster it will get squeezed out. A gas bubble can only grow at constant pressure if the surrounding solvent is sufficiently supersaturated to overcome the surface tension or if the surface layer provides sufficient reaction to overcome surface tension. Clean bubbles that are sufficiently small will collapse due to surface tension if the supersaturation is low. Bubbles with semipermeable surfaces will either stabilise at a specific radius depending on the pressure, the composition of the surface layer, and the supersaturation, or continue to grow indefinitely, if larger than the critical radius.
|
|
If the solvent is sufficiently supersaturated, the diffusion of gas into the bubble will exceed the rate at which it diffuses back into solution, and if this excess pressure is greater than the pressure due to surface tension the bubble will continue to grow. When a bubble grows, the surface tension decreases, and the interior pressure drops, allowing gas to diffuse in faster, and diffuse out slower, so the bubble grows or shrinks in a positive feedback situation. The growth rate is reduced as the bubble grows because the surface area increases as the square of the radius, while the volume increases as the cube of the radius. If the external pressure is reduced due to reduced hydrostatic pressure during ascent, the bubble will also grow, and conversely, an increased external pressure will cause the bubble to shrink, but may not cause it to be eliminated entirely if a compression-resistant surface layer exists.
|
|
These transmembrane transporters are localised both in the cytoplasmic membrane and in the MM, but in an inverted orientation; this configuration allows them to generate an efflux of Fe2+ ions at the cytoplasmic membrane, and an influx of this same ion at the MM. This step is strictly controlled by a cytochrome-dependent redox system, which is not yet fully explained and appears to be species-specific. During the final stage of the process, the magnetite crystal nucleation is by action of transmembrane proteins with acidic and basic domains. One of these proteins, called Mms6, has also been employed for the artificial synthesis of magnetite, where its presence allows the production of crystals homogeneous in shape and size. It is likely that many other proteins associated with the MM could be involved in other roles, such as generation of supersaturated concentrations of iron, maintenance of reducing conditions, oxidisation of iron, and partial reduction and dehydration of hydrated iron compounds.
|
|
Platinum nanoparticles are typically synthesized either by the reduction of platinum ion precursors in solution with a stabilizing or capping agent to form colloidal nanoparticles, or by the impregnation and reduction of platinum ion precursors in a micro-porous support such as alumina. Some common examples of platinum precursors include potassium hexachloroplatinate (K2PtCl6) or platinous chloride (PtCl2) Different combinations of precursors, such as ruthenium chloride (RuCl3) and chloroplatinic acid (H2PtCl6), have been used to synthesize mixed-metal nanoparticles Some common examples of reducing agents include hydrogen gas (H2), sodium borohydride (NaBH4) and ethylene glycol (C2H6O2), although other alcohols and plant-derived compounds have also been used. As the platinum metal precursor is reduced to neutral platinum metal (Pt0), the reaction mixture becomes supersaturated with platinum metal and the Pt0 begins to precipitate in the form of nanoscale particles. A capping agent or stabilizing agent such as sodium polyacrylic acid or sodium citrate is often used to stabilize the nanoparticle surfaces, and prevents the aggregation and coalescence of the nanoparticles.
|
|
The Wegener–Bergeron–Findeisen process (after Alfred Wegener, Tor Bergeron and Walter Findeisen), (or "cold-rain process") is a process of ice crystal growth that occurs in mixed phase clouds (containing a mixture of supercooled water and ice) in regions where the ambient vapor pressure falls between the saturation vapor pressure over water and the lower saturation vapor pressure over ice. This is a subsaturated environment for liquid water but a supersaturated environment for ice resulting in rapid evaporation of liquid water and rapid ice crystal growth through vapor deposition. If the number density of ice is small compared to liquid water, the ice crystals can grow large enough to fall out of the cloud, melting into rain drops if lower level temperatures are warm enough. The Bergeron process, if occurring at all, is much more efficient in producing large particles than is the growth of larger droplets at the expense of smaller ones, since the difference in saturation pressure between liquid water and ice is larger than the enhancement of saturation pressure over small droplets (for droplets large enough to considerably contribute to the total mass).
|
|