The Buda Hills ( Hungarian : Budai-hegység ) are a low mountain range of numerous hills which dot the Buda side of Budapest , capital of Hungary . The most famous ones located within city limits are Gellért Hill , Castle Hill , Rózsadomb , Sváb Hill [ hu ] , János Hill , Széchenyi Hill [ hu ] and Eagle Hill . These hills consist of both nature and residential areas.
36-490: The Budaörs dolomite of Anisian-Carnian age ( Triassic period ) is the oldest formation which crops out in the Buda Hills. Younger Triassic succession is composed of cherty dolomite and limestone (basin facies ), and dolomite combined with limestone (platform facies). The Triassic surface is composed of karstified carbonates , which are overlain by an Upper Eocene succession made of conglomerate beds. During
72-456: 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. 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
108-424: A drug in this form is simple and allows for the measurement of very precise dosages. Primarily, it provides a means for drugs with very low solubility to be made into aqueous solutions . In addition, some drugs can undergo supersaturation inside the body despite being ingested in a crystalline form. This phenomenon is known as in vivo supersaturation . The identification of supersaturated solutions can be used as
144-413: A few cases the opposite effect occurs. The example of sodium sulfate in water is well-known and this was why it was used in early studies of solubility. 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
180-530: 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". 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
216-513: A liquid. A supersaturated solution is in a metastable state; it may return to equilibrium by separation of the excess of solute from the solution, by dilution of the solution by adding solvent, or by increasing the solubility of the solute in the solvent. 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
252-466: A more stable phase (such as partially ordered dolomite) during periodical intervals of dissolution and re-precipitation. The general principle governing the course of this irreversible geochemical reaction has been coined "breaking Ostwald's step rule ". High diagenetic temperatures, such as those of groundwater flowing along deeply rooted fault systems affecting some sedimentary successions or deeply buried limestone rocks allocate dolomitization . But
288-492: A pH buffer and as a magnesium source. Pastures can be limed with dolomitic lime to raise their pH and where there is a magnesium deficiency. Dolomite is also used as the substrate in marine (saltwater) aquariums to help buffer changes in the pH of the water. Calcined dolomite is also used as a catalyst for destruction of tar in the gasification of biomass at high temperature. Particle physics researchers like to build particle detectors under layers of dolomite to enable
324-479: A period of weeks. Supersaturation may be encountered when attempting to crystallize a protein. The solubility of a gas in a liquid increases with increasing gas pressure. When the external pressure is reduced, the excess gas comes out of solution. Fizzy drinks are made by subjecting the liquid to carbon dioxide , under pressure. In champagne the CO 2 is produced naturally in the final stage of fermentation . When
360-425: 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 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
396-508: A tool for marine ecologists to study the activity of organisms and populations. Photosynthetic organisms release O 2 gas into the water. Thus, an area of the ocean supersaturated with O 2 gas can likely determined to be rich with photosynthetic activity. Though some O 2 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. Supersaturation in vapor phase
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#1732773203991432-513: Is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite (see Dolomite (rock) ). An alternative name sometimes used for the dolomitic rock type is dolostone. As stated by Nicolas-Théodore de Saussure the mineral dolomite was probably first described by Carl Linnaeus in 1768. In 1791, it was described as a rock by the French naturalist and geologist Déodat Gratet de Dolomieu (1750–1801), first in buildings of
468-530: Is an important petroleum reservoir rock, and serves as the host rock for large strata-bound Mississippi Valley-Type (MVT) ore deposits of base metals such as lead , zinc , and copper . Where calcite limestone is uncommon or too costly, dolomite is sometimes used in its place as a flux for the smelting of iron and steel. Large quantities of processed dolomite are used in the production of float glass . In horticulture , dolomite and dolomitic limestone are added to soils and soilless potting mixes as
504-465: Is in fine powder form, it does not rapidly dissolve or effervesce (fizz) in cold dilute hydrochloric acid as calcite does. Crystal twinning is common. Solid solution exists between dolomite, the iron -dominant ankerite and the manganese -dominant kutnohorite . Small amounts of iron in the structure give the crystals a yellow to brown tint. Manganese substitutes in the structure also up to about three percent MnO. A high manganese content gives
540-502: Is likely result from complexation of both magnesium and calcium by carboxylic acids comprising EPS. Vast deposits of dolomite are present in the geological record, but the mineral is relatively rare in modern environments. Reproducible, inorganic low-temperature syntheses of dolomite are yet to be performed. Usually, the initial inorganic precipitation of a metastable "precursor" (such as magnesium calcite) can easily be achieved. The precursor phase will theoretically change gradually into
576-433: 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. It is not enough for molecules of water to form an ice lattice at saturation pressures; they require a surface to condense on to or conglomerations of liquid water molecules of water to freeze. For these reasons, relative humidities over ice in
612-441: Is usually present in the expansion process through steam nozzles that operate with superheated steam at the inlet, which transitions to saturated state at the outlet. Supersaturation thus becomes an important factor to be taken into account in the design of steam turbines , as this results in an actual mass flow of steam through the nozzle being about 1 to 3% greater than the theoretically calculated value that would be expected if
648-837: The Kelvin equation , the Gibbs–Thomson effect and the Poynting effect . The International Association for the Properties of Water and Steam ( IAPWS ) provides a special equation for the Gibbs free energy in the metastable-vapor region of water in its Revised Release on the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam . All thermodynamic properties for
684-767: The Rio de Janeiro coast of Brazil , namely, Lagoa Vermelha and Brejo do Espinho. There are many other localities where modern dolomite forms, notably along sabkhas in the Persian Gulf , but also in sedimentary basins bearing gas hydrates and hypersaline lakes. It is often thought that dolomite nucleates with the help of sulfate-reducing bacteria (e.g. Desulfovibrio brasiliensis ), but other microbial metabolisms have been also found to mediate in dolomite formation. In general, low-temperature dolomite may occur in natural supersaturated environments rich in extracellular polymeric substances (EPS) and microbial cell surfaces. This
720-412: The bottle or can is opened some gas is released in the form of bubbles. Release of gas from supersaturated tissues can cause an underwater diver to suffer from decompression sickness (a.k.a. the bends) when returning to the surface. This can be fatal if the released gas obstructs critical blood supplies causing ischaemia in vital tissues. Dissolved gases can be released during oil exploration when
756-505: The characteristics of the analyte. The characteristics of supersaturation have practical applications in terms of pharmaceuticals . By creating a supersaturated solution of a certain drug, it can be ingested in liquid form. The drug can be made driven into a supersaturated state through any normal mechanism and then prevented from precipitating out by adding precipitation inhibitors. Drugs in this state are referred to as "supersaturating drug delivery services," or "SDDS." Oral consumption of
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#1732773203991792-520: The crystals a rosy pink color. Lead , zinc , and cobalt also can substitute in the structure for magnesium. The mineral dolomite is closely related to huntite Mg 3 Ca(CO 3 ) 4 . Because dolomite can be dissolved by slightly acidic water, areas where dolomite is an abundant rock-forming mineral are important as aquifers and contribute to karst terrain formation. Modern dolomite formation has been found to occur under anaerobic conditions in supersaturated saline lagoons such as those at
828-428: The detectors to detect the highest possible number of exotic particles. Because dolomite contains relatively minor quantities of radioactive materials, it can insulate against interference from cosmic rays without adding to background radiation levels. In addition to being an industrial mineral, dolomite is highly valued by collectors and museums when it forms large, transparent crystals. The specimens that appear in
864-408: The expanding steam underwent a reversible adiabatic process through equilibrium states. In these cases supersaturation occurs due to the fact that the expansion process develops so rapidly and in such a short time, that the expanding vapor cannot reach its equilibrium state in the process, behaving as if it were superheated . Hence the determination of the expansion ratio, relevant to the calculation of
900-488: The fans' close location to the andesite source rocks. The clasts could have been then transported by periodic streams along the valleys. The Late Eocene transgression reworked accumulated terrestrial sediments. The most important hills of the region are: Dolomite (mineral) Dolomite ( / ˈ d ɒ l . ə ˌ m aɪ t , ˈ d oʊ . l ə -/ ) is an anhydrous carbonate mineral composed of calcium magnesium carbonate , ideally CaMg(CO 3 ) 2 . The term
936-520: The magnesite quarry exploited in Eugui, Esteribar, Navarra (Spain) are considered among the best in the world. Supersaturation In physical chemistry , supersaturation occurs with a solution when the concentration of a solute exceeds the concentration specified by the value of solubility at equilibrium . Most commonly the term is applied to a solution of a solid in a liquid , but it can also be applied to liquids and gases dissolved in
972-429: The mass flow through the nozzle, must be done using an adiabatic index of approximately 1.3, like that of the superheated steam, instead of 1.135, which is the value that should have to be used for a quasi-static adiabatic expansion in the saturated region. 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
1008-515: The metastable-vapor region of water can be derived from this equation by means of the appropriate relations of thermodynamic properties to the Gibbs free energy. 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
1044-471: The mineral is also volumetrically important in some Neogene platforms never subjected to elevated temperatures. Under such conditions of diagenesis the long-term activity of the deep biosphere could play a key role in dolomitization, since diagenetic fluids of contrasting composition are mixed as a response to Milankovitch cycles . A recent biotic synthetic experiment claims to have precipitated ordered dolomite when anoxygenic photosynthesis proceeds in
1080-515: The old city of Rome, and later as samples collected in the Tyrolean Alps . Nicolas-Théodore de Saussure first named the mineral (after Dolomieu) in March 1792. The mineral dolomite crystallizes in the trigonal-rhombohedral system. It forms white, tan, gray, or pink crystals. Dolomite is a double carbonate, having an alternating structural arrangement of calcium and magnesium ions. Unless it
1116-479: The period from the terminal Cretaceous to Priabonian , the area was a karstic terrestrial environment displaying distinct relief differences. It was also the time when Triassic formations were eroded. The continental period (ended by the transgression in Late Eocene ) was characterized by the formation of small fans at the slope foot. The fans contained substantial quantities of andesite clasts thanks to
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1152-456: The presence of manganese(II). A still perplexing example of an organogenic origin is that of the reported formation of dolomite in the urinary bladder of a Dalmatian dog, possibly as the result of an illness or infection. Dolomite is used as an ornamental stone, a concrete aggregate, and a source of magnesium oxide , as well as in the Pidgeon process for the production of magnesium . It
1188-399: The same salt that is being crystallized in order to promote crystallization. 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
1224-401: The solution is subsequently lowered it briefly becomes supersaturated and then the compound crystallizes out until chemical equilibrium at the lower temperature is achieved. 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
1260-460: 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. Désiré Gernez contributed to this research by discovering that nuclei must be of
1296-407: 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". 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
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