1 Mpa Berapa Bar



Pascal Unit Wikipedia

Mengonversi bar [bar] megapascal [MPa] • Pengonversi Satuan Umum • Pressure, Stress, Young’s Modulus Converter • Kalkulator Ringkas

1 bar [bar] = 0,1 megapascal [MPa]

A working pressure setting of most pressure cookers is 1 standard atmosphere or 15 psi

A balloon bursting at TranslatorsCafe.com office

Pressure is defined as force per unit of area. If the same force is applied to two areas, a smaller and a larger one, the pressure would be greater for the smaller area. You will probably agree that it is less scary to be stepped on by someone wearing running shoes than by someone wearing stilettos. For example, if you try pushing a sharp knife down through a carrot or a tomato, you will cut it. The area where the force is applied is small, so the pressure is high enough to cut through the object. If, on the other hand, you use a blunt knife, you will not be able to cut through because the area is greater and the pressure is lower as a result.

The SI unit for pressure is the pascal, which is newton per square meter.

Gauge Pressure

In some cases pressure of gases is measured as the difference between the total or absolute pressure and the atmospheric pressure. This is known as gauge pressure, and it is the pressure measured when determining the air pressure in car tires. Measuring devices often show gauge pressure, although absolute pressure sensors are also in use.

Atmospheric Pressure

Atmospheric or air pressure is the pressure of air in a given environment. It usually refers to the weight of the column of atmospheric air above the unit surface area. Atmospheric pressure affects weather and temperature. Considerable changes in the atmospheric pressure cause discomfort for people and animals. Decrease in atmospheric pressure can cause psychological and physical discomfort for people and animals, or even death. For this reason, airplane cabins, which would otherwise experience low air pressure at cruising heights, are artificially pressurized.

Aneroid pressure gauge is based on a pressure sensor — a set of metallic bellows, which change their shape in response to the pressure, which, in turn, rotates the needle by a linkage connected to the bellows

Atmospheric pressure decreases with the increase in altitude. People and animals, who live at high altitudes, for example in the Himalayas, adapt to the low pressure. Travelers, on the other hand, often need to take precautionary measures to avoid discomfort.Some people, such as mountaineers, are affected by altitude sickness, caused by the oxygen deficiency in the blood. This condition can become chronic with prolonged exposure. It typically happens at altitudes above 2,400 meters. In severe cases people may be affected by high altitude cerebral or pulmonary edema. To prevent altitude-related health problems, medical professionals recommend avoiding depressants such as alcohol and sleeping pills, and also to hydrate well, and to ascend to higher altitudes at a slow pace, for example on foot, instead of using transportation. Additional recommendations include diet high in carbohydrates, and resting well, especially for individuals who ascended quickly. This will allow the body to combat the oxygen shortage, which results from low atmospheric pressure, by producing more red blood cells to carry oxygen, and by increasing heart and respiratory rates, among other adaptations.

Emergency treatment for severe altitude sickness has to be provided immediately. It is paramount to bring the patient to lower altitudes where the pressure is higher, preferably to the altitude below 2400 meters above the sea level. Treatment also includes medication, and use of the Gamow Bag. It is a portable light-weight container that can be pressurized by using a foot pump. The patient is put inside this bag to simulate lower altitudes. This is an emergency treatment and the patient still needs to be transported to lower altitudes.

Low atmospheric pressure is also used by athletes, who sleep in simulated high-altitude environments but exercise in normal conditions. This helps their bodies to adapt to high altitudes and start producing greater amounts of red blood cells, which, in turn, increases the amount of oxygen carried through their body, and enhances their athletic abilities. For this purpose athletes often use altitude tents or canopies, which have low atmospheric pressure inside.

NASA space shuttle Atlantis exhibit at the Kennedy Space Center

Astronauts and pilots who have to work at high altitudes use pressure suits to compensate for the low air pressure. Full-pressure suits are used in space, while partial-pressure suits, which provide counter-pressure and assist breathing at high altitude are used by pilots.

Hydrostatic Pressure

Hydrostatic pressure is the pressure of fluid caused by the force of gravity. It is an important factor not only in engineering and physics, but also in medicine. For example, blood pressure is the hydrostatic pressure of blood on the blood vessel walls. It usually refers to arterial pressure, and is represented by two numbers: systolic or maximum pressure and diastolic or minimum pressure during a heartbeat. The instrument used to measure blood pressure is called a sphygmomanometer. Millimeters of mercury are used as units for blood pressure measurements, even in countries like the USA and the UK, where inches are used for measuring length.

Digital blood pressure meter or sphygmomanometer

A Pythagorean cup is an interesting device, which uses the principles of hydrostatic pressure. According to legend, it was designed by Pythagoras to moderate wine drinking. Other sources mention that this cup was meant to regulate the drinking of water during a drought. It usually has a stem and always has a dome inside of it, which allows liquid to enter from the bottom through an embedded pipe. This pipe runs from the bottom of the stem of the cup to the top of the dome, then bends, and opens into the cup, as in the illustration. Liquid enters the pipe through this opening. The other side of the pipe that runs through the stem also has an opening at the bottom of the stem. The design and operating principles of a Pythagorean cup are similar to the ones in modern toilet bowls. If the liquid that fills the cup is above the top of the pipe, then it spills through the bottom of the cup, due to hydrostatic pressure. If the liquid is below that level, one can use the cup in a conventional way.

Pressure in Geology

A quartz crystal illuminated with a red laser pointer

Pressure is a critical element in geology. Formation of gemstones requires pressure, both for the natural and laboratory-made synthetic gemstones. Crude oil is also formed by intense pressure and heat from remnants of plants and animals. In contrast to gemstones, which mostly form in rock formations, oil is generally formed in the beds of water such as rivers and seas. Organic material is covered with sand and silt, which gradually accumulates above it. The weight of the water above and the sand exert pressure. With time, these materials are buried deeper and deeper and reach several kilometers below the Earth surface. As the temperature increases by about 25 °C per each kilometer below the surface, it reaches 50-80 °C at these depths. Depending on the total temperature and temperature fluctuation, gas may be created instead of oil.

Diamond tools

Natural Gemstones

Gemstone formation varies, but often pressure is an important factor. Diamonds, for example, are created in the mantle of the Earth, where intense pressure and temperatures are present. They then emerge on or near the surface during volcanic eruptions, when magma carries them up. Some diamonds come to Earth inside meteorites, and scientists speculate that their formation on other planets is similar to Earth.

Synthetic Gemstones

Synthetic gemstone industry on the industrial scale started in the 1950s, and it is currently expanding. Some consumers still prefer mined gemstones, but there is a shift in consumer preferences, especially because of the many problems with gemstone mining that came to light recently. Many consumers choose synthetic gemstones not only because of the lower price, but also because they believe that lab-produced stones have fewer issues such as human right violations, funding wars and conflicts, and child labor.

One of the methods for growing diamonds in the laboratory, the high pressure high temperature (HPHT) method, is by subjecting carbon to high temperature over 1000 °C and pressure of about 5 GPa. Generally, diamond seeds are used as a base and graphite is a high-purity carbon source from which the new diamond grows. This method is common, especially for making gemstones, because it is cheap compared to the alternative methods. These laboratory-grown diamonds have similar and sometimes superior properties to the naturally-formed diamonds, depending on the manufacturing method. They are often colored, however.

Diamonds are widely used for industrial purposes due to their properties, especially hardness. Optical qualities, as well as heat conductivity and resistance to alkalis and acids are also valued. Cutting tools use diamond coating, and diamond powder is included in abrasive materials. Currently a large portion of industrial diamonds is made in the laboratories because synthetic production is cheaper than mining, and also because the demand for industrial diamonds cannot be met through mining exclusively.

Some companies now offer memorial diamonds. Those are grown from the carbon that was extracted from the hair or the cremation ashes of the deceased. The manufacturers market these diamonds as a memento to celebrate the life of the loved ones, and they are gaining popularity, especially on the markets of wealthy countries such as Japan and the USA.

The High Pressure High Temperature (HPHT) Process

The high pressure high temperature process is mainly used when working with synthetic diamonds. However, it is now also used on natural diamonds to enhance or adjust their color properties. Presses of different design can be used in the process. Cubic-type presses are the most expensive and complicated. They are mainly used for enhancing or changing colors in the natural diamonds. The growth within the capsule of the press is about 0.5 carats of rough diamond per day.

References

Artikel ini ditulis oleh Kateryna Yuri.

Unit Converter articles were edited and illustrated by Anatoly Zolotkov

Anda kesulitan menerjemahkan satuan pengukuran ke bahasa lainnya? Bantuan tersedia! Posting pertanyaan Anda di TCTerms dan Anda akan mendapatkan jawaban dari penerjemah teknis berpengalaman dalam hitungan menit.


Page 2

1 bar [bar] = 0,1 megapascal [MPa]

A working pressure setting of most pressure cookers is 1 standard atmosphere or 15 psi

A balloon bursting at TranslatorsCafe.com office

Pressure is defined as force per unit of area. If the same force is applied to two areas, a smaller and a larger one, the pressure would be greater for the smaller area. You will probably agree that it is less scary to be stepped on by someone wearing running shoes than by someone wearing stilettos. For example, if you try pushing a sharp knife down through a carrot or a tomato, you will cut it. The area where the force is applied is small, so the pressure is high enough to cut through the object. If, on the other hand, you use a blunt knife, you will not be able to cut through because the area is greater and the pressure is lower as a result.

The SI unit for pressure is the pascal, which is newton per square meter.

Gauge Pressure

In some cases pressure of gases is measured as the difference between the total or absolute pressure and the atmospheric pressure. This is known as gauge pressure, and it is the pressure measured when determining the air pressure in car tires. Measuring devices often show gauge pressure, although absolute pressure sensors are also in use.

Atmospheric Pressure

Atmospheric or air pressure is the pressure of air in a given environment. It usually refers to the weight of the column of atmospheric air above the unit surface area. Atmospheric pressure affects weather and temperature. Considerable changes in the atmospheric pressure cause discomfort for people and animals. Decrease in atmospheric pressure can cause psychological and physical discomfort for people and animals, or even death. For this reason, airplane cabins, which would otherwise experience low air pressure at cruising heights, are artificially pressurized.

Aneroid pressure gauge is based on a pressure sensor — a set of metallic bellows, which change their shape in response to the pressure, which, in turn, rotates the needle by a linkage connected to the bellows

Atmospheric pressure decreases with the increase in altitude. People and animals, who live at high altitudes, for example in the Himalayas, adapt to the low pressure. Travelers, on the other hand, often need to take precautionary measures to avoid discomfort.Some people, such as mountaineers, are affected by altitude sickness, caused by the oxygen deficiency in the blood. This condition can become chronic with prolonged exposure. It typically happens at altitudes above 2,400 meters. In severe cases people may be affected by high altitude cerebral or pulmonary edema. To prevent altitude-related health problems, medical professionals recommend avoiding depressants such as alcohol and sleeping pills, and also to hydrate well, and to ascend to higher altitudes at a slow pace, for example on foot, instead of using transportation. Additional recommendations include diet high in carbohydrates, and resting well, especially for individuals who ascended quickly. This will allow the body to combat the oxygen shortage, which results from low atmospheric pressure, by producing more red blood cells to carry oxygen, and by increasing heart and respiratory rates, among other adaptations.

Emergency treatment for severe altitude sickness has to be provided immediately. It is paramount to bring the patient to lower altitudes where the pressure is higher, preferably to the altitude below 2400 meters above the sea level. Treatment also includes medication, and use of the Gamow Bag. It is a portable light-weight container that can be pressurized by using a foot pump. The patient is put inside this bag to simulate lower altitudes. This is an emergency treatment and the patient still needs to be transported to lower altitudes.

Low atmospheric pressure is also used by athletes, who sleep in simulated high-altitude environments but exercise in normal conditions. This helps their bodies to adapt to high altitudes and start producing greater amounts of red blood cells, which, in turn, increases the amount of oxygen carried through their body, and enhances their athletic abilities. For this purpose athletes often use altitude tents or canopies, which have low atmospheric pressure inside.

NASA space shuttle Atlantis exhibit at the Kennedy Space Center

Astronauts and pilots who have to work at high altitudes use pressure suits to compensate for the low air pressure. Full-pressure suits are used in space, while partial-pressure suits, which provide counter-pressure and assist breathing at high altitude are used by pilots.

Hydrostatic Pressure

Hydrostatic pressure is the pressure of fluid caused by the force of gravity. It is an important factor not only in engineering and physics, but also in medicine. For example, blood pressure is the hydrostatic pressure of blood on the blood vessel walls. It usually refers to arterial pressure, and is represented by two numbers: systolic or maximum pressure and diastolic or minimum pressure during a heartbeat. The instrument used to measure blood pressure is called a sphygmomanometer. Millimeters of mercury are used as units for blood pressure measurements, even in countries like the USA and the UK, where inches are used for measuring length.

Digital blood pressure meter or sphygmomanometer

A Pythagorean cup is an interesting device, which uses the principles of hydrostatic pressure. According to legend, it was designed by Pythagoras to moderate wine drinking. Other sources mention that this cup was meant to regulate the drinking of water during a drought. It usually has a stem and always has a dome inside of it, which allows liquid to enter from the bottom through an embedded pipe. This pipe runs from the bottom of the stem of the cup to the top of the dome, then bends, and opens into the cup, as in the illustration. Liquid enters the pipe through this opening. The other side of the pipe that runs through the stem also has an opening at the bottom of the stem. The design and operating principles of a Pythagorean cup are similar to the ones in modern toilet bowls. If the liquid that fills the cup is above the top of the pipe, then it spills through the bottom of the cup, due to hydrostatic pressure. If the liquid is below that level, one can use the cup in a conventional way.

Pressure in Geology

A quartz crystal illuminated with a red laser pointer

Pressure is a critical element in geology. Formation of gemstones requires pressure, both for the natural and laboratory-made synthetic gemstones. Crude oil is also formed by intense pressure and heat from remnants of plants and animals. In contrast to gemstones, which mostly form in rock formations, oil is generally formed in the beds of water such as rivers and seas. Organic material is covered with sand and silt, which gradually accumulates above it. The weight of the water above and the sand exert pressure. With time, these materials are buried deeper and deeper and reach several kilometers below the Earth surface. As the temperature increases by about 25 °C per each kilometer below the surface, it reaches 50-80 °C at these depths. Depending on the total temperature and temperature fluctuation, gas may be created instead of oil.

Diamond tools

Natural Gemstones

Gemstone formation varies, but often pressure is an important factor. Diamonds, for example, are created in the mantle of the Earth, where intense pressure and temperatures are present. They then emerge on or near the surface during volcanic eruptions, when magma carries them up. Some diamonds come to Earth inside meteorites, and scientists speculate that their formation on other planets is similar to Earth.

Synthetic Gemstones

Synthetic gemstone industry on the industrial scale started in the 1950s, and it is currently expanding. Some consumers still prefer mined gemstones, but there is a shift in consumer preferences, especially because of the many problems with gemstone mining that came to light recently. Many consumers choose synthetic gemstones not only because of the lower price, but also because they believe that lab-produced stones have fewer issues such as human right violations, funding wars and conflicts, and child labor.

One of the methods for growing diamonds in the laboratory, the high pressure high temperature (HPHT) method, is by subjecting carbon to high temperature over 1000 °C and pressure of about 5 GPa. Generally, diamond seeds are used as a base and graphite is a high-purity carbon source from which the new diamond grows. This method is common, especially for making gemstones, because it is cheap compared to the alternative methods. These laboratory-grown diamonds have similar and sometimes superior properties to the naturally-formed diamonds, depending on the manufacturing method. They are often colored, however.

Diamonds are widely used for industrial purposes due to their properties, especially hardness. Optical qualities, as well as heat conductivity and resistance to alkalis and acids are also valued. Cutting tools use diamond coating, and diamond powder is included in abrasive materials. Currently a large portion of industrial diamonds is made in the laboratories because synthetic production is cheaper than mining, and also because the demand for industrial diamonds cannot be met through mining exclusively.

Some companies now offer memorial diamonds. Those are grown from the carbon that was extracted from the hair or the cremation ashes of the deceased. The manufacturers market these diamonds as a memento to celebrate the life of the loved ones, and they are gaining popularity, especially on the markets of wealthy countries such as Japan and the USA.

The High Pressure High Temperature (HPHT) Process

The high pressure high temperature process is mainly used when working with synthetic diamonds. However, it is now also used on natural diamonds to enhance or adjust their color properties. Presses of different design can be used in the process. Cubic-type presses are the most expensive and complicated. They are mainly used for enhancing or changing colors in the natural diamonds. The growth within the capsule of the press is about 0.5 carats of rough diamond per day.

References

Artikel ini ditulis oleh Kateryna Yuri.

Unit Converter articles were edited and illustrated by Anatoly Zolotkov

Anda kesulitan menerjemahkan satuan pengukuran ke bahasa lainnya? Bantuan tersedia! Posting pertanyaan Anda di TCTerms dan Anda akan mendapatkan jawaban dari penerjemah teknis berpengalaman dalam hitungan menit.


Page 3

1 Bar [bar] = 0,1 Megapascal [MPa]

Die meisten Druckkochtöpfe haben einen Arbeitsdruck von 1 Normatmosphäre oder 15 psi

Ein Ballon zerplatzt im Büro von TranslatorsCafe.com

Druck ist ein Maß für die Kraft pro Flächeneinheit. Wenn die gleiche Kraft auf zwei Flächen ausgeübt wird, einer kleinen und einer größeren Fläche, wäre der Druck für die kleinere Fläche größer. Jeder würde wahrscheinlich zustimmen, dass es weniger beängstigend ist, wenn einem jemand mit Turnschuhen auf die Füße tritt, als wenn dieser jemand Stöckelschuhe tragen würde. Wenn man beispielsweise ein scharfes Messer auf eine Tomate oder Karotte drückt, wird man schneiden. Die Fläche, auf die der Druck ausgeübt wird, ist klein, sodass der Druck hoch genug ist, um durch das Objekt durchzuschneiden. Wenn man andererseits ein stumpfes Messer verwendet, wird man nicht schneiden können, da die Fläche größer ist und der Druck dadurch geringer.

Im internationalen System der Einheiten (Système International d’Unités, SI) lautet die Einheit für Druck Pascal, was ein Newton pro Quadratmeter entspricht.

Atmosphärische Druckdifferenz

In einigen Fällen wird Druck von Gasen als Unterschied zwischen dem Gesamt- oder Absolutdruck und dem atmosphärischen Druck gemessen. Dies wird atmosphärische Druckdifferenz genannt und ist der Druck, der gemessen wird, wenn man den Luftdruck von Autoreifen bestimmt. Messgeräte zeigen die atmosphärische Druckdifferenz, obwohl es auch Sensoren für absoluten Druck gibt.

Atmosphärischer Druck

Atmosphärischer oder Luftdruck ist der Druck von Luft in der Umgebung. Er bezieht sich in der Regel auf das Gewicht einer Säule atmosphärischer Luft über der Flächeneinheit. Der Luftdruck wirkt sich auf das Wetter und die Temperatur aus. Erhebliche Änderungen beim Luftdruck bewirken Unbehagen bei Menschen und Tieren. Verringerung beim atmosphärischen Druck können psychologisches und physisches Unwohlsein bei Menschen und Tieren auslösen oder sogar Tod. Aus diesem Grund wird bei Flugzeugen, die sonst niedrigem Luftdruck ausgesetzt sind, ein künstlicher Druckausgleich durchgeführt.

Aneroid pressure gauge is based on a pressure sensor — a set of metallic bellows, which change their shape in response to the pressure, which, in turn, rotates the needle by a linkage connected to the bellows

Der Luftdruck sinkt mit der größeren Höhe. Menschen und Tiere, die in großen Höhen leben, zum Beispiel im Himalaya, passen sich an den niedrigen Luftdruck an. Reisende, andererseits, müssen Vorkehrungen treffen, um Unwohlsein zu vermeiden. Manche Menschen, zum Beispiel manche Bergsteiger, leiden unter der Höhenkrankheit, die durch den Sauerstoffmangel im Blut verursacht wird. Dieser Zustand kann bei längerer Verweildauer chronisch werden. Dies passiert üblicherweise ab Höhen von über 2.400 Metern. In schweren Fällen kann ein Hirn- oder Lungenödem verursacht werden. Um höhenbedingte Gesundheitsprobleme zu vermeiden, empfehlen Mediziner, Sedative wie Alkohol oder Schlafmittel zu vermeiden. Man sollte zudem gut hydriert sein und größere Höhen langsam erreichen, beispielsweise zu Fuß, statt mithilfe eines Transportmittels. Zusätzliche Empfehlungen umfassen einen hohen Anteil an Kohlenhydraten bei der Nahrung und gut ausruhen, insbesondere für Personen, die schnell aufsteigen. Dadurch kann der Körper den Sauerstoffmangel, der aufgrund des niedrigen Luftdrucks auftreten kann, besser kompensieren, indem er mehr rote Blutzellen erzeugt, die Sauerstoff transportieren. Zudem erhöht er neben anderen Anpassungen die Herz- und Atemfrequenz.

Bei schwerer Höhenkrankheit muss sofort eine Notfallbehandlung erfolgen. Es ist äußerst wichtig, den Patienten auf geringere Höhe zu bringen, wo der Luftdruck höher ist, vorzugsweise unter eine Höhe von 2400 Metern über Normalnull. Die Behandlung umfasst Medikamente und den Einsatz eines Überdrucksacks. Ein Überdrucksack ist ein tragbarer, leichtgewichtiger Behälter, der mittels Fußpumpe unter Druck gesetzt werden kann. Der Patient begibt sich in den Sack und wird durch die Simulation geringerer Höhe behandelt. Dies ist nur eine Notfallmaßnahme. Der Patient muss dennoch auf eine tatsächliche geringere Höhe gebracht werden.

Niedriger Luftdruck wird auch von Sportlern genutzt, die in simulierten Umgebungen großer Höhe schlafen und unter normalen Bedingungen trainieren. Dadurch kann der Körper sich an die geringe Höhe gewöhnen und mehr rote Blutzellen produzieren, womit mehr Sauerstoff transportiert wird und die Fähigkeiten des Sportlers gesteigert werden. Zu diesem Zweck verwenden Sportler Höhenzelte oder -baldachins, die innen einen geringen Luftdruck aufweisen.

NASA-Spaceshuttle Atlantis: Ausstellung im Kennedy Space Center

Astronauten und Piloten, die in großen Höhen arbeiten, verwenden Druckanzüge, um niedrigen Luftdruck zu kompensieren. Mehrzweck-Druckanzüge werden im Weltraum eingesetzt, Teildruckanzüge, die Gegendruck liefern und das Atmen in großen Höhen erleichtern, werden von Piloten getragen.

Hydrostatischer Druck

Hydrostatischer Druck ist Druck von Flüssigkeit, der durch die Schwerkraft erzeugt wird. Er ist ein wichtiger Faktor, nicht nur in der Konstruktion und Physik, sondern auch in der Medizin. Zum Beispiel ist der Blutdruck der hydrostatische Druck von Blut an den Wänden der Blutgefäße. Er bezieht sich in der Regel auf den Druck in den Arterien und wird anhand zweier Zahlen angezeigt: dem systolischen oder Oberwert und dem diastolischen oder Unterwert während eines Herzschlags. Das Gerät zur Messung des Blutdrucks wird Sphygmomanometer genannt. Millimeter-Quecksilbersäulen werden als Einheit für Blutdruckmessungen genutzt, selbst in Ländern wie den USA und Großbritannien, in denen sonst Zoll zur Längenmessung verwendet wird.

Digitales Blutdruckmessgerät bzw. Sphygmomanometer

Ein Pythagoreischer Becher ist ein interessantes Gerät, das auf dem hydrostatischen Druck beruht. Nach einer Legende wurde er von Pythagoras entwickelt, um ein moderates Trinken von Wein zu erreichen. Andere Quellen sagen, der Becher galt als Regulationsmittel für Wasser während einer Dürre. Der Becher enthält in der Mitte üblicherweise einen Schaft mit einer Haube, wodurch die Flüssigkeit vom Becherboden in ein integriertes Röhrchen gelangt. Dieses Röhrchen geht vom Becherboden hinauf bis zur Kuppelspitze und knickt dann wieder nach unten durch den Schaft ab. Flüssigkeit gerät durch den Becherboden in das Röhrchen. Am anderen Ende des Röhrchens (im Schaft) befindet sich ebenfalls eine Öffnung. Das Design und Funktionsprinzip des Pythagoreischen Bechers ist ähnlich dem moderner Toilettenschüsseln. Steigt der flüssige Becherinhalt über das Röhrchen, wird er aufgrund des hydrostatischen Drucks am Becherboden im Röhrchen hoch gedrückt und tritt am anderen Ende aus. Bleibt der Flüssigkeitsstand unter der oberen Röhrchenebene, kann man den Becher wie üblich verwenden.

Druck in der Geologie

Ein Quarzkristall mit einem roten Laserpointer beleuchtet

Druck ist ein wesentliches Element in der Geologie. Die Bildung von Edelsteinen erfordert Druck, sowohl bei natürlichen als auch bei im Labor hergestellten synthetischen Edelsteinen. Rohöl bildet sich ebenfalls aufgrund von starkem Druck und Hitze auf Pflanzen- und Tierüberreste. In Gegensatz zu Edelsteinen, die sich meistens in Steinformationen bilden, ist Öl im Allgemeinen in Gewässerbetten wie Flüssen und Meere zu finden. Organisches Material wird von Sand und Schlamm überlagert, die sich nach und nach aufbauen. Das Gewicht des Wassers und der Sand üben Druck aus. Mit der Zeit wird das Material mehr und mehr überlagert und ist dann mehrere Kilometer unter der Erdoberfläche zu finden. Da die Temperatur sich um etwa 25 °C pro Kilometer unter der Oberfläche erwärmt, erreicht es 50-80 °C in diesen Tiefen. Je nach Gesamttemperatur und Temperaturfluktuation entsteht statt Öl eventuell Gas.

Diamantwerkzeuge

Natürliche Edelsteine

Die Edelsteinbildung variiert, aber häufig ist Druck ein wichtiger Faktor. Diamanten werden zum Beispiel im Erdmantel gebildet, in dem starker Druck und hohe Temperaturen bestehen. Sie tauchen dann an oder nahe der Oberfläche aufgrund von vulkanischer Aktivität auf, wenn sie von Magma nach oben getragen werden. Einige Diamanten gelangen im Inneren von Meteoriten auf die Erde. Wissenschaftler spekulieren, dass ihre Entstehung auf anderen Planeten ähnlich wie bei der Erde erfolgt.

Synthetische Edelsteine

Synthetische Edelsteinerzeugung auf Industrieebene begann in den 1950ern und wird derzeit ausgedehnt. Einige Verbraucher bevorzugen immer noch natürliche, in Minen geförderte Edelsteine. Aber dies ist einem Wandel unterzogen, insbesondere wegen der vielen, bekannt gewordenen Probleme beim Edelsteinbergbau. Viele Verbraucher entscheiden sich für synthetische Edelsteine nicht nur wegen des günstigeren Preises, sondern auch, weil sie denken, dass industriell gefertigte Steine weniger Probleme wie Menschenrechtsverletzungen, Kriegsfinanzierung und Kinderarbeit bedeuten.

Eine Methode zur Herstellung von Diamanten im Labor besteht in der Hochdruck-Hochtemperatur-Methode (high-pressure oil, high-temperature, HPHT), bei der Kohlenstoff einer hohen Temperatur über 1000 °C und einem Druck von etwa 5 GPa ausgesetzt wird. In der Regel werden Diamantenkristalle als Basis genutzt, während Graphit eine hochreine Kohlenstoffquelle ist, mithilfe der der neue Diamant wächst. Diese Methode wird häufig genutzt, insbesondere für Edelsteine, da sie im Vergleich zu alternativen Methoden günstiger ist. Die im Labor gezogenen Diamanten haben ähnliche und manchmal bessere Eigenschaften, als die natürlich entstandenen Diamanten. Dies hängt von der Herstellungsweise ab. Sie sind jedoch häufig farbig.

Diamanten werden in vielen Bereichen aufgrund ihrer Eigenschaften, insbesondere der Härte, eingesetzt. Optische Merkmale sowie die Wärmeleitfähigkeit und Widerstandsfähigkeit gegenüber Laugen und Säuren sind ebenfalls geschätzt. Schneidewerkzeuge verfügen über eine Diamantbeschichtung und Diamantpuder wird in Schleifmaterialien eingesetzt. Derzeit wird ein Großteil der in der Industrie verwendeten Diamanten im Labor hergestellt, da die synthetische Produktion billiger ist als der Abbau in Minen. Darüber hinaus kann der Bedarf an in der Industrie genutzten Diamanten nicht allein durch natürliche Vorkommen gedeckt werden.

Einige Unternehmen bieten nun Gedenk-Diamanten an. Diese wurden aus dem Kohlenstoff hergestellt, der aus den Haaren oder der Asche von Verstorbenen extrahiert wurde. Hersteller vermarkten diese Diamanten als Andenken, um das Leben des Verstorbenen zu feiern. Sie gewinnen an Popularität, insbesondere in Wohlstandsländern wie Japan und die USA.

Das Hochdruck-Hochtemperatur-Verfahren (HPHT)

Das Hochdruck-Hochtemperatur-Verfahren wird hauptsächlich bei der Arbeit mit synthetischen Diamanten verwendet. Es wird jedoch inzwischen auch bei natürlichen Diamanten eingesetzt, um deren Farbqualitäten anzupassen. Pressen unterschiedlichen Designs können in diesem Verfahren zum Einsatz kommen. Würfelartige Pressen sind die teuersten und kompliziertesten. Sie werden hauptsächlich verwendet, um die Farben von natürlichen Diamanten zu verbessern oder zu ändern. Das Wachstum in der Kapsel der Presse beträgt etwa 0,5 Karat Rohdiamant pro Tag.

Weitere Informationen

Dieser Artikel wurde von Kateryna Yuri verfasst.

Unit Converter articles were edited and illustrated by Anatoly Zolotkov

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1 bar [bar] = 0.1 megapascal [MPa]

A working pressure setting of most pressure cookers is 1 standard atmosphere or 15 psi

A balloon bursting at TranslatorsCafe.com office

Pressure is defined as force per unit of area. If the same force is applied to two areas, a smaller and a larger one, the pressure would be greater for the smaller area. You will probably agree that it is less scary to be stepped on by someone wearing running shoes than by someone wearing stilettos. For example, if you try pushing a sharp knife down through a carrot or a tomato, you will cut it. The area where the force is applied is small, so the pressure is high enough to cut through the object. If, on the other hand, you use a blunt knife, you will not be able to cut through because the area is greater and the pressure is lower as a result.

The SI unit for pressure is the pascal, which is newton per square meter.

Gauge Pressure

In some cases pressure of gases is measured as the difference between the total or absolute pressure and the atmospheric pressure. This is known as gauge pressure, and it is the pressure measured when determining the air pressure in car tires. Measuring devices often show gauge pressure, although absolute pressure sensors are also in use.

Atmospheric Pressure

Atmospheric or air pressure is the pressure of air in a given environment. It usually refers to the weight of the column of atmospheric air above the unit surface area. Atmospheric pressure affects weather and temperature. Considerable changes in the atmospheric pressure cause discomfort for people and animals. Decrease in atmospheric pressure can cause psychological and physical discomfort for people and animals, or even death. For this reason, airplane cabins, which would otherwise experience low air pressure at cruising heights, are artificially pressurized.

Aneroid pressure gauge is based on a pressure sensor — a set of metallic bellows, which change their shape in response to the pressure, which, in turn, rotates the needle by a linkage connected to the bellows

Atmospheric pressure decreases with the increase in altitude. People and animals, who live at high altitudes, for example in the Himalayas, adapt to the low pressure. Travelers, on the other hand, often need to take precautionary measures to avoid discomfort.Some people, such as mountaineers, are affected by altitude sickness, caused by the oxygen deficiency in the blood. This condition can become chronic with prolonged exposure. It typically happens at altitudes above 2,400 meters. In severe cases people may be affected by high altitude cerebral or pulmonary edema. To prevent altitude-related health problems, medical professionals recommend avoiding depressants such as alcohol and sleeping pills, and also to hydrate well, and to ascend to higher altitudes at a slow pace, for example on foot, instead of using transportation. Additional recommendations include diet high in carbohydrates, and resting well, especially for individuals who ascended quickly. This will allow the body to combat the oxygen shortage, which results from low atmospheric pressure, by producing more red blood cells to carry oxygen, and by increasing heart and respiratory rates, among other adaptations.

Emergency treatment for severe altitude sickness has to be provided immediately. It is paramount to bring the patient to lower altitudes where the pressure is higher, preferably to the altitude below 2400 meters above the sea level. Treatment also includes medication, and use of the Gamow Bag. It is a portable light-weight container that can be pressurized by using a foot pump. The patient is put inside this bag to simulate lower altitudes. This is an emergency treatment and the patient still needs to be transported to lower altitudes.

Low atmospheric pressure is also used by athletes, who sleep in simulated high-altitude environments but exercise in normal conditions. This helps their bodies to adapt to high altitudes and start producing greater amounts of red blood cells, which, in turn, increases the amount of oxygen carried through their body, and enhances their athletic abilities. For this purpose athletes often use altitude tents or canopies, which have low atmospheric pressure inside.

NASA space shuttle Atlantis exhibit at the Kennedy Space Center

Astronauts and pilots who have to work at high altitudes use pressure suits to compensate for the low air pressure. Full-pressure suits are used in space, while partial-pressure suits, which provide counter-pressure and assist breathing at high altitude are used by pilots.

Hydrostatic Pressure

Hydrostatic pressure is the pressure of fluid caused by the force of gravity. It is an important factor not only in engineering and physics, but also in medicine. For example, blood pressure is the hydrostatic pressure of blood on the blood vessel walls. It usually refers to arterial pressure, and is represented by two numbers: systolic or maximum pressure and diastolic or minimum pressure during a heartbeat. The instrument used to measure blood pressure is called a sphygmomanometer. Millimeters of mercury are used as units for blood pressure measurements, even in countries like the USA and the UK, where inches are used for measuring length.

Digital blood pressure meter or sphygmomanometer

A Pythagorean cup is an interesting device, which uses the principles of hydrostatic pressure. According to legend, it was designed by Pythagoras to moderate wine drinking. Other sources mention that this cup was meant to regulate the drinking of water during a drought. It usually has a stem and always has a dome inside of it, which allows liquid to enter from the bottom through an embedded pipe. This pipe runs from the bottom of the stem of the cup to the top of the dome, then bends, and opens into the cup, as in the illustration. Liquid enters the pipe through this opening. The other side of the pipe that runs through the stem also has an opening at the bottom of the stem. The design and operating principles of a Pythagorean cup are similar to the ones in modern toilet bowls. If the liquid that fills the cup is above the top of the pipe, then it spills through the bottom of the cup, due to hydrostatic pressure. If the liquid is below that level, one can use the cup in a conventional way.

Pressure in Geology

A quartz crystal illuminated with a red laser pointer

Pressure is a critical element in geology. Formation of gemstones requires pressure, both for the natural and laboratory-made synthetic gemstones. Crude oil is also formed by intense pressure and heat from remnants of plants and animals. In contrast to gemstones, which mostly form in rock formations, oil is generally formed in the beds of water such as rivers and seas. Organic material is covered with sand and silt, which gradually accumulates above it. The weight of the water above and the sand exert pressure. With time, these materials are buried deeper and deeper and reach several kilometers below the Earth surface. As the temperature increases by about 25 °C per each kilometer below the surface, it reaches 50-80 °C at these depths. Depending on the total temperature and temperature fluctuation, gas may be created instead of oil.

Diamond tools

Natural Gemstones

Gemstone formation varies, but often pressure is an important factor. Diamonds, for example, are created in the mantle of the Earth, where intense pressure and temperatures are present. They then emerge on or near the surface during volcanic eruptions, when magma carries them up. Some diamonds come to Earth inside meteorites, and scientists speculate that their formation on other planets is similar to Earth.

Synthetic Gemstones

Synthetic gemstone industry on the industrial scale started in the 1950s, and it is currently expanding. Some consumers still prefer mined gemstones, but there is a shift in consumer preferences, especially because of the many problems with gemstone mining that came to light recently. Many consumers choose synthetic gemstones not only because of the lower price, but also because they believe that lab-produced stones have fewer issues such as human right violations, funding wars and conflicts, and child labor.

One of the methods for growing diamonds in the laboratory, the high pressure high temperature (HPHT) method, is by subjecting carbon to high temperature over 1000 °C and pressure of about 5 GPa. Generally, diamond seeds are used as a base and graphite is a high-purity carbon source from which the new diamond grows. This method is common, especially for making gemstones, because it is cheap compared to the alternative methods. These laboratory-grown diamonds have similar and sometimes superior properties to the naturally-formed diamonds, depending on the manufacturing method. They are often colored, however.

Diamonds are widely used for industrial purposes due to their properties, especially hardness. Optical qualities, as well as heat conductivity and resistance to alkalis and acids are also valued. Cutting tools use diamond coating, and diamond powder is included in abrasive materials. Currently a large portion of industrial diamonds is made in the laboratories because synthetic production is cheaper than mining, and also because the demand for industrial diamonds cannot be met through mining exclusively.

Some companies now offer memorial diamonds. Those are grown from the carbon that was extracted from the hair or the cremation ashes of the deceased. The manufacturers market these diamonds as a memento to celebrate the life of the loved ones, and they are gaining popularity, especially on the markets of wealthy countries such as Japan and the USA.

The High Pressure High Temperature (HPHT) Process

The high pressure high temperature process is mainly used when working with synthetic diamonds. However, it is now also used on natural diamonds to enhance or adjust their color properties. Presses of different design can be used in the process. Cubic-type presses are the most expensive and complicated. They are mainly used for enhancing or changing colors in the natural diamonds. The growth within the capsule of the press is about 0.5 carats of rough diamond per day.

References

This article was written by Kateryna Yuri

Unit Converter articles were edited and illustrated by Anatoly Zolotkov

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1 بار [بار] = 0.1 ميجا باسكال [الرمز MPa]

إعداد ضغط العمل لمعظم طناجر الضغط هو 1 ضغط جوي عياري أو 15 رطل لكل بوصة مربعة

انفجار بالون في مكتب TranslatorsCafe.com

يُعرف الضغط بأنه القوة على وحدة مساحة. إذا تم تطبيق نفس القوة على مساحتين، أحدهما صغيرة والأخرى كبيرة، فسيكون الضغط أكبر بالنسبة للمنطقة الأصغر. فمن الأرجح أنك ستوافق أن يخطو عليك شخص يرتدي حذاء الجري على أن يخطو عليك شخص يرتدي حذاء بطرف مدبب كالخنجر. على سبيل المثال، إذا حاولت دفع سكينًا حادًا داخل ثمرة جزر أو طماطم، فسوف تقطعها. فالمساحة التي تُطبق عليها القوة صغيرة، وبالتالي يكون الضغط مرتفعًا بما يكفي لقطع الشيء. ومن ناحية أخرى، إذا استخدمت سكينًا غير حاد، فلن تكون قادرًا على اختراق المساحة نظرًا لأن المساحة أكبر ويكون الضغط أقل نتيجة لذلك.

وحدة قياس الضغط وفقًا للنظام الدولي للوحدات هي الباسكال، وهي النيوتن لكل متر مربع.

مدلول مقياس الضغط

في بعض الحالات، يتم قياس ضغط الغاز على أنه الفرق بين الضغط الكلي أو المطلق والضغط الجوي. يُعرف ذلك باسم مدلول مقياس الضغط، وهو الضغط الذي يتم قياسه عند تحديد ضغط الهواء في إطارات السيارة. غالبًا ما تظهر أجهزة قياس الضغط مدلول مقياس الضغط، على الرغم من أن أجهزة استشعار الضغط المطلق تُستخدم لذلك أيضًا.

الضغط الجوي

الضغط الجوي أو ضغط الهواء هو ضغط الهواء في بيئة معينة. ويشير عادةً إلى وزن عمود الهواء الجوي فوق وحدة مساحة سطح. ويؤثر الضغط الجوي على الطقس ودرجة الحرارة. تسبب التغييرات الكبيرة في الضغط الجوي الانزعاج للبشر والحيوانات. يسبب انخفاض الضغط الجوي عدم الراحة النفسية والجسدية للأشخاص والحيوانات، وقد يسبب الوفاة. ولهذا السبب، فإن كابينة الطائرة، والتي من شأنها أن تواجه ضغط هواء منخفض في الارتفاعات، تكون مكيفة الضغط اصطناعيًا.

يعتمد مقياس الضغط المعدني على مستشعر ضغط - مجموعة من خوارات هواء معدنية مضغوطة بضغط جوي واحد، والتي تغير شكلها استجابة للضغط، الذي بدوره يقوم بتدوير الإبرة عن طريق رابط متصل بالخوارات

حيث ينخفض الضغط الجوي مع زيادة الارتفاع. فالبشر والحيوانات، الذين يعيشون على ارتفاعات عالية، على سبيل المثال في جبال الهيمالايا، يتكيفون مع الضغط المنخفض. المسافرين، من ناحية أخرى، غالبًا ما يحتاجون إلى اتخاذ تدابير وقائية لتجنب الإحساس بعد الراحة. ويعاني بعض الأشخاص، مثل متسلقي الجبال، من داء المرتفعات، الذي ينتج عن نقص الأوكسجين في الدم. ويمكن أن تصبح هذه الحالة مزمنة مع التعرض الطويل للضغط. ويحدث ذلك عادًة على ارتفاعات أعلى من 2400 متر. وفي الحالات الشديدة، قد يتأثر الأشخاص بالوذمة الرئوية أو الدماغية الناتجة عن الوجود بأماكن مرتفعة. ولمنع حدوث مشاكل صحية متعلقة بالمرتفعات، يوصي العاملون في المجال الطبي بتجنب تناول المسكنات مثل الكحول والحبوب المنومة، وكذلك شرب قدر جيد من الماء، وصعود المرتفعات بوتيرة بطيئة، على سبيل المثال سيرًا على الأقدام، بدلاً من استخدام وسائل النقل. وتشمل التوصيات الإضافية اتباع نظام غذائي غني بالكربوهيدرات، مع أخذ قسط جيد من الراحة، خاصةً بالنسبة للأفراد الذين صعدوا بسرعة، حيث سيتيح ذلك للجسم التغلب على نقص الأكسجين الناتج عن انخفاض الضغط الجوي، عن طريق إنتاج المزيد من خلايا الدم الحمراء لنقل الأكسجين، وزيادة معدلات عمل القلب والجهاز التنفسي، من بين التكيفات الأخرى.

يجب على الفور توفير علاج طارئ للمصابين بداء المرتفعات الشديد. فمن الضروري جدًا نقل المريض إلى ارتفاعات منخفضة حيث يكون الضغط أعلى، ويفضل أن يكون ذلك على ارتفاع أقل من 2400 متر فوق مستوى سطح البحر. ويشمل العلاج أيضا تناول الأدوية، واستخدام حقيبة جامو، وهي حاوية محمولة خفيفة الوزن يمكن تعديل ضغطها باستخدام مضخة تعمل عن طريق القدم. حيث يتم وضع المريض داخل هذه الحقيبة لمحاكاة الارتفاعات المنخفضة. وهي تعتبر علاجًا طارئًا حيث لا يزال المريض بحاجة إلى النقل إلى ارتفاعات منخفضة.

الرياضيون الذين ينامون في بيئات عالية الارتفاع، ولكنهم يمارسون الرياضة في ظروف طبيعية، يستخدمون أيضًا الضغط الجوي المنخفض. وهذا يساعد أجسامهم على التكيف مع الارتفاعات العالية والبدء في إنتاج كميات أكبر من خلايا الدم الحمراء، والتي بدورها، تزيد كمية الأوكسجين في الجسم، وتعزز قدراتهم الرياضية. ولهذا الغرض، يستخدم الرياضيون غالبًا خيام أو مظلات الأماكن المرتفعة، والتي يكون الضغط الجوي منخفضًا بداخلها.

مكوك الفضاء أتلانتس التابع لناسا المعروض في مركز كينيدي للفضاء

يستخدم رواد الفضاء والطيارون الذين يتعين عليهم العمل على ارتفاعات عالية بزلة تكييف الضغط للتعويض عن انخفاض ضغط الهواء. يتم استخدام بذلة الضغط المكيفة بالكامل في الفضاء، بينما يتم استخدام بدلات الضغط الجزئي، والتي توفر ضغطًا مضادًا وتساعد في التنفس على الارتفاعات العالية بواسطة الطيارين.

الضغط الهيدروستاتيكي أو ضغط الماء الساكن

ضغط الماء الساكن هو ضغط السائل الناتج عن قوة الجاذبية. وهو عامل مهم ليس فقط في الهندسة والفيزياء، ولكن أيضًا في الطب. على سبيل المثال، ضغط الدم هو الضغط الهيدروستاتيكي للدم على جدران الأوعية الدموية. ويشير عادةً إلى الضغط الشرياني، ويمثله رقمان: الضغط الانقباضي أو الحد الأقصى والضغط الانبساطي أو الضغط الأدنى أثناء ضربات القلب. تسمى الأداة المستخدمة لقياس ضغط الدم مقياس ضغط الدم. ويتم استخدام ملليمتر من الزئبق كوحدات لقياس ضغط الدم، حتى في بلدان مثل الولايات المتحدة الأمريكية والمملكة المتحدة، حيث يتم استخدام البوصات لقياس الطول.

مقياس ضغط الدم الرقمي أو مقياس ضغط الدم

كأس فيثاغورس هو جهاز هام حيث إنه يستخدم أسس الضغط الهيدروستاتيكي. فوفقًا للأسطورة، تم تصميمه من قبل فيثاغورس للتقليل من شرب الخمر. وتذكر مصادر أخرى أن هذا الكأس كان يهدف إلى تنظيم شرب الماء أثناء فترات الجفاف. عادةً ما يكون له جذع وله دومًا قبة بداخله، مما يسمح للسائل بالدخول من أسفل عبر أنبوب داخلي. حيث يمتد هذا الأنبوب من أسفل جذع الكأس إلى أعلى القبة، ثم ينحني، ويصب في الكأس، كما في الرسم التوضيحي. ويدخل السائل إلى الأنبوب من خلال هذه الفتحة. يحتوي الجانب الآخر من الأنبوب الذي يمر عبر الجذع أيضًا على فتحة أسفل الجذع. تتشابه مبادئ التصميم والتشغيل الخاصة بكأس فيثاغورس مع المبادئ الموجودة في مقاعد المراحيض الحديثة. إذا كان السائل الذي يملأ الكوب أعلى سطح الأنبوب، فإنه يصب عبر قاع الكأس، بسبب الضغط الهيدروستاتيكي. وإذا كان السائل أقل من هذا المستوى، فيمكن للمرء استخدام الكأس بطريقة تقليدية.

الضغط في علم طبقات الأرض

بلورة كوارتز مضاءة بمؤشر ليزر أحمر

يعد الضغط عنصرًا هامًا في علم طبقات الأرض. يتطلب تكوين الأحجار الكريمة ضغطًا، سواء بالنسبة للأحجار الكريمة الطبيعية أو المصنوعة في المختبرات. ويتكون النفط الخام أيضا من بقايا النباتات والحيوانات بفعل الضغط الشديد والحرارة. وعلى عكس الأحجار الكريمة، والتي تتشكل في الغالب في التكوينات الصخرية، يتشكل النفط بشكل عام في قاع الماء مثل الأنهار والبحار. حيث تُغطى المواد العضوية بالرمل والطمي، والتي تتراكم تدريجيا فوقها. حيث يتسبب وزن الماء والرمل أعلاه في إحداث الضغط. ومع مرور الوقت، يتم دفن هذه المواد أعمق فأعمق وتصل إلى عدة كيلومترات تحت سطح الأرض. حيث ترتفع درجة الحرارة بنحو 25 درجة مئوية لكل كيلومتر تحت السطح، لتصل إلى 50-80 درجة مئوية عند هذه الأعماق. وقد يتم تشكل الغاز بدلاً من النفط اعتمادًا على درجة الحرارة الكلية وتقلب درجات الحرارة.

الأدوات الماسية

الأحجار الكريمة الطبيعية

يختلف تكوين الأحجار الكريمة، لكن الضغط في كثير من الأحيان هو العامل المهم. فالماس، على سبيل المثال، يتم تكوينه في قشرة الأرض، حيث يوجد ضغط ودرجات حرارة شديدة. ثم تظهر على السطح أو بالقرب منه أثناء الانفجارات البركانية، عندما تحملها الصهارة لأعلى. وبعض الماس يأتي إلى الأرض داخل النيازك، ويتكهن العلماء بأن تكوينها على كواكب أخرى يشبه طريقة تكوينها على الأرض.

الأحجار الكريمة الاصطناعية

بدأت صناعة الأحجار الكريمة الاصطناعية على المستوى الصناعي في الخمسينيات، وتتوسع هذه الصناعة حاليًا. إلا أن بعض المستهلكين يفضلون الأحجار الكريمة المستخرجة من الأرض، ولكن يوجد تحول في تفضيلات المستهلك، خاصة بسبب العديد من المشاكل المتعلقة باستخراج الأحجار الكريمة التي ظهرت مؤخراً. يختار العديد من المستهلكين الأحجار الكريمة الاصطناعية، ليس فقط بسبب انخفاض الأسعار، ولكن أيضًا لأنهم يعتقدون أن الأحجار التي تنتجها المعامل لها عدد أقل من المشاكل مثل انتهاكات حقوق الإنسان وتمويل الحروب والصراعات وعمالة الأطفال.

تتمثل إحدى طرق استنبات الألماس في المختبر، بطريقة الضغط العالي وارتفاع درجة الحرارة (الاختصار HPHT)، حيث يتم تعريض الكربون لدرجة حرارة عالية تزيد عن 1000 درجة مئوية وضغط يصل إلى حوالي 5 .جيجا باسكال. وبشكل عام، يتم استخدام بذور الماس كقاعدة وكذلك الجرافيت، وهو مصدر كربوني عالي النقاء ينمو منه الماس الجديد. وتعتبر هذه الطريقة شائعة، خاصة لصنع الأحجار الكريمة، لأنها رخيصة مقارنة بالطرق البديلة. تتمتع هذه الماسات المزروعة في المختبرات بخصائص متشابهة وأحيانًا متفوقة على الألماس المشكل بشكل طبيعي، اعتمادًا على طريقة التصنيع. ومع ذلك، فغالبًا ما تكون تلك الماسات ملونة.

يستخدم الماس على نطاق واسع للأغراض الصناعية بسبب خصائصه، وخاصة لصلابته. كما يتم كذلك تفضيله بسبب خصائصه البصرية، والتوصيل الحراري ومقاومته للقلويات والأحماض. تستخدم أدوات القطع طلاء من الماس، ويتم تضمين مسحوق الماس في المواد الكاشطة. حاليًا يتم صنع جزء كبير من الماس الصناعي في المختبرات لأن الإنتاج الصناعي أرخص من استخراجه عن طريق التعدين، وكذلك لأنه لا يمكن تلبية الطلب على الماس الصناعي من خلال التعدين بشكل حصري.

وبعض الشركات تعرض الآن الماس التذكاري. وتستنبت تلك الماسات من الكربون الذي تم استخراجه من الشعر أو رماد الحرق من المتوفى. يقوم المنتجون بتسويق هذا الألماس كتذكار للاحتفال بحياة أحبائهم، ويلقى ذلك شعبية خاصة في أسواق الدول الغنية مثل اليابان والولايات المتحدة.

عملية الضغط العالي وارتفاع درجة الحرارة

تستخدم عملية الضغط العالي وارتفاع درجة الحرارة بشكل أساسي عند العمل بالماس الصناعي. بيد أن هذه العملية تستخدم الآن أيضًا على الماس الطبيعي لتعزيز أو ضبط خصائص ألوانه. ويمكن استخدام مكابس ذات تصميم مختلف في هذه العملية. والمكابس ذات النوع المكعب هي الأكثر تكلفة وتعقيدًا. فهي تستخدم أساسًا لتعزيز أو تغيير ألوان الماس الطبيعي. حيث يكون نمو الماس داخل كبسولة المكبس حوالي 0.5 قيراط من الماس الخام يوميًا.

المراجع

هذا المقال بقلم Kateryna Yuri.

Unit Converter articles were edited and illustrated by Anatoly Zolotkov


Page 6

1 bar [bar] = 0,1 megapascal [MPa]

Pentru majoritatea oalelor sub presiune, presiunea de funcționare este setată la 1 atmosferă standard sau 15 psi

Explozia unui balon într-un birou TranslatorsCafe.com

Presiunea este definită ca fiind forța pe unitate de suprafață. Dacă aceeași forță este aplicată asupra a două suprafețe, una mai mică și una mai mare, presiunea va fi mai mare pe suprafața mică. Fără îndoială, este mai înspăimântoare ideea de a fi călcat de cineva care poartă tocuri subțiri decât de cineva cu adidași. De exemplu, dacă încercați să înfigeți un cuțit ascuțit într-un morcov sau într-o roșie, le veți tăia. Suprafața asupra căreia este aplicată forța este mică, așadar presiunea este destul de mare pentru a străpunge obiectul. În schimb, cu un cuțit bont nu le veți putea străpunge, pentru că suprafața este mai mare și, ca urmare, presiunea este mai mică.

Unitatea de măsură a presiunii în SI este pascalul, echivalent cu un newton pe metru pătrat.

Presiunea manometrică

În unele cazuri, presiunea gazelor se măsoară pe baza diferenței dintre presiunea totală sau absolută și presiunea atmosferică. Aceasta este presiunea manometrică, fiind acea presiune măsurată pentru a determina presiunea aerului din anvelopele auto. Dispozitivele de măsurare indică deseori presiunea manometrică, deși se folosesc și senzori de presiune absolută.

Presiunea atmosferică

Presiunea atmosferică sau a aerului este presiunea pe care o are aerul într-un mediu anume. De obicei se referă la greutatea coloanei de aer pe unitatea de suprafață a unei arii. Presiunea atmosferică influențează condițiile meteo și temperatura. Modificările de amploare ale presiunii atmosferice provoacă oamenilor și animalelor un anume disconfort. Scăderea presiunii atmosferice poate provoca oamenilor și animalelor un disconfort fizic și psihic, sau chiar moartea. Așa se explică presurizarea artificială a cabinelor de avion, care în caz contrar ar avea o presiune scăzută la altitudinea de croazieră.

Aneroid pressure gauge is based on a pressure sensor — a set of metallic bellows, which change their shape in response to the pressure, which, in turn, rotates the needle by a linkage connected to the bellows

Presiunea atmosferică scade pe măsură ce crește altitudinea. Oamenii și animalele care trăiesc la altitudine mare, de exemplu în munții Himalaya, se adaptează la presiunea scăzută. În schimb, turiștii trebuie în mod normal să își ia măsuri de precauție pentru a evita un posibil disconfort. Unele persoane, cum ar fi alpiniștii, sunt afectați de răul de altitudine, provocat de lipsa oxigenului în sânge. Dacă expunerea este prelungită, afecțiunea devine cronică. Problemele intervin de obicei la altitudini de peste 2 400 de metri. În cazuri grave, apare edemul cerebral sau pulmonar de mare altitudine. Pentru prevenirea afecțiunilor legate de altitudine, medicii recomandă evitarea substanțelor depresoare, cum ar fi alcoolul și somniferele, și hidratarea corectă, precum și parcurgerea traseului în înălțime în ritm moderat, preferabil pe jos decât cu un mijloc de transport. Alte recomandări se referă la adoptarea unei diete cu mulți carbohidrați și a unui program de odihnă suficientă, îndeosebi pentru cei care urcă repede. Astfel, veți oferi corpului mijloace de combatere a lipsei oxigenului provocate de presiunea atmosferică scăzută: numărul de celule roșii care transportă oxigen va crește, odată cu frecvența cardiacă și respiratorie, printre alte mecanisme de adaptare.

Intervenția de urgență în cazul răului de altitudine în formă gravă trebuie acordată imediat. Este esențială aducerea pacientului la altitudini mai mici, unde presiunea este mai mare, preferabil la o altitudine sub 2400 metri peste nivelul mării. Tratamentul mai include tratament medicamentos și folosirea dispozitivului Gamow Bag. Este vorba de un container portabil și ușor, care poate fi presurizat cu o pompă de picior. Pacientul este pus în acest sac care simulează altitudini mici. Tratamentul este doar de urgență, pacientul trebuind neapărat să fie transportat la altitudini mai mici.

Presiunea atmosferică scăzută este folosită și de atleți, care dorm într-un mediu care simulează altitudini înalte, dar se antrenează în condiții normale. Astfel, corpul trece printr-un proces de adaptare la altitudini înalte și începe să producă o cantitate mai mare de celule roșii în sânge, determinând creșterea cantității de oxigen transportat prin corp și îmbunătățind performanțele sportive. În acest scop, atleții pot folosi corturi sau camere de simulare a altitudinii înalte (dispozitiv hipoxic), care creează în interior un mediu cu presiune atmosferică scăzută.

Naveta spațială Atlantis, construită de NASA expusă la Kennedy Space Center

Astronauții și piloții care trebuie să lucreze la altitudini înalte folosesc costume presurizate pentru a compensa presiunea scăzută a aerului. În spațiu se folosesc costume integral presurizate, iar piloții au costume parțial presurizate, care asigură contrapresiunea și facilitează respirația la altitudini mari.

Presiunea hidrostatică

Presiunea hidrostatică este presiunea unui fluid provocată de forța de gravitație. Este un factor important, nu numai în științele inginerești și fizică, dar și în medicină. De exemplu, presiunea sângelui este presiunea hidrostatică a sângelui asupra pereților vaselor de sânge. Aceasta se numește presiune arterială, fiind reprezentată de două valori: presiunea sistolică, adică maximă, și cea diastolică, adică minimă, pe parcursul unei bătăi de inimă. Instrumentul folosit pentru a măsura presiunea sângelui se numește sfigmomanometru. Unitatea de măsură a presiunii sângelui este milimetru coloană de mercur, chiar și în țări ca SUA sau Marea Britanie, unde unitatea standard pentru lungime este inch-ul.

Aparat digital pentru măsurarea presiunii arteriale sau sfigmomanometru

Cupa lui Pitagora este un dispozitiv interesant, care aplică principiul presiunii hidrostatice. Legenda spune că a fost inventată de Pitagora pentru a modera consumul de vin. Alte surse menționează că această cupă era un instrument de cumpătare pe timp de secetă. Cupa are de obicei un picior și obligatoriu o coloană în interior, prevăzută cu un canal care permite lichidului să circule. Canalul începe la baza piciorului paharului, traversează piciorul și coloana, face o cotitură și se termină printr-un orificiu în cupă, după cum se vede în imagine. Lichidul intră în canal prin această gură de intrare. La celălalt capăt, de la baza piciorului, unde începe canalul, se află gura de ieșire. Proiectarea și principiul de funcționare a cupei lui Pitagora sunt similare celor care explică funcționarea bazinului vasului de toaletă. Dacă lichidul din cupă depășește vârful coloanei, atunci va curge prin gura de ieșire de la bază, din cauza presiunii hidrostatice. Dacă lichidul rămâne sub acest nivel, cupa poate fi folosită normal.

Presiunea în geologie

Un cristal de cuarț iluminat cu un indicator laser roșu

Presiunea este un element esențial în geologie. Formarea pietrelor prețioase necesită presiune, atât în cazul celor naturale, cât și a celor produse în laborator. Și țițeiul se formează prin acțiunea unei presiuni importante și a căldurii emanate de resturile de plante și animale. Spre deosebire de pietrele prețioase, care apar îndeosebi în formațiuni de rocă, petrolul se formează de regulă în albiile râurilor și mărilor. Pe materia organică se depune nisip și nămol, care formează treptat un strat de acoperire. Greutatea apei și a nisipului produce presiune. Cu timpul, aceste materii sunt împinse din ce în ce mai adânc, până la câțiva kilometri de la suprafață. Temperatura solului crește cu aproximativ 25 °C pe kilometru în adâncime, ajungând la 50-80 °C în straturile respective. În funcție de temperatura totală și de fluctuația de temperatură, se pot forma gaze în loc de petrol.

Instrumente din diamant

Geme naturale

Formarea pietrelor prețioase variază, dar presiunea este deseori un factor important. De exemplu, diamantele iau naștere în straturile de adâncime al Pământului, unde sunt temperaturi mari și presiune înaltă. Apoi, ele apar la suprafață sau în apropiere de suprafață cu ocazia erupțiilor vulcanice, fiind propulsate de magmă. Unele diamante ajung pe Pământ în interiorul meteoriților, iar oamenii de știință susțin că modul în care acestea se formează pe alte planete ar fi similar cu cel de pe Pământ.

Geme sintetice

Industria gemelor sintetice la scară industrială a apărut în anii 1950 și este în continuă dezvoltare. Unii consumatorii încă preferă pietrele prețioase obținute prin extracție naturală, dar se constată un decalaj în preferințele consumatorilor, în special din cauza numeroaselor probleme din domeniul extragerii pietrelor prețioase, date recent publicității. Mulți consumatori preferă astfel gemele sintetice nu numai pentru că sunt mai ieftine, dar și din convingere, considerând că pietrele obținute sintetic nu implică probleme legate de violarea drepturilor omului, finanțarea conflictelor și a războiului, exploatarea copiilor.

Una dintre metodele folosite pentru cultivarea diamantelor în laboratoare, anume metoda de presiune și temperatură înalte (HPHT), constă în supunerea carbonului la temperaturi mari, peste 1 000 °C și la o presiune de aproximativ 5 GPa. În general, se folosește ca bază un miez de diamant, grafitul fiind o sursă de carbon de mare puritate, pe care se cultivă diamante noi. Metoda este des întâlnită, în special pentru crearea de geme, pentru că este ieftină față de metodele alternative. Aceste diamante cultivate în laborator au proprietăți similare, ba chiar superioare uneori celor formate natural, în funcție de metoda de fabricare. Totuși, sunt deseori colorate.

Diamantele sunt folosite pe scară largă în scopuri industriale datorită proprietăților lor, în special durității. La fel de apreciate sunt și calitățile optice ale acestora, precum și conductivitatea termică și rezistența la alcalini și acizi. Instrumentele de tăiat au un strat suflat cu diamant, iar materialele abrazive conțin pudră de diamant. În prezent, o mare parte din diamantele folosite în industrie provin din filiera fabricării sintetice în laborator, mai ieftină decât extragerea, care nici nu poate satisface cererea de diamante industriale.

Unele companii oferă în prezent diamante memoriale. Acestea sunt formate pe baza carbonului extras din părul sau din cenușa obținută din incinerarea unei persoane decedate. Producătorii le prezintă drept un simbol al comemorării persoanelor dragi, aceste diamante bucurându-se de un real succes, îndeosebi în rândul cumpărătorilor din țările bogate, cum ar fi Japonia și SUA.

Tehnica de presiune și temperatură înalte (HPHT)

Tehnica de presiune și temperatură înalte este folosită în principal când se lucrează cu diamante sintetice. Cu toate acestea, în prezent se aplică și diamantelor naturale, pentru a ameliora sau retușa culorile acestora. În cadrul procesului se pot folosi prese de diferite tipuri. Presele cubice sunt cele mai scumpe și mai complicate, fiind folosite îndeosebi pentru a ameliora sau a schimba culoarea diamantelor naturale. Creșterea produsă în capsulă este în jur de 0,5 carate diamant brut pe zi.

Referințe

Acest articol a fost scris de către Kateryna Yuri.

Unit Converter articles were edited and illustrated by Anatoly Zolotkov

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Page 7

1 бар [бар] = 0,1 мегапаскаль [МПа]

Давление в большинстве кастрюль-скороварок во время работы равно 1 атмосфере или 15 паскалям

Воздушный шар, лопающийся в офисе TranslatorsCafe.com

В физике давление определяется как сила, действующая на единицу площади поверхности. Если две одинаковые силы действуют на одну большую и одну меньшую поверхность, то давление на меньшую поверхность будет больше. Согласитесь, гораздо страшнее, если вам на ногу наступит обладательница шпилек, чем хозяйка кроссовок. Например, если надавить лезвием острого ножа на помидор или морковь, овощ будет разрезан пополам. Площадь поверхности лезвия, соприкасающаяся с овощем, мала, поэтому давление достаточно велико, чтобы разрезать этот овощ. Если же надавить с той же силой на помидор или морковь тупым ножом, то, скорее всего, овощ не разрежется, так как площадь поверхности ножа теперь больше, а значит давление — меньше.

В системе СИ давление измеряется в паскалях, или ньютонах на квадратный метр.

Относительное давление

Иногда давление измеряется как разница абсолютного и атмосферного давления. Такое давление называется относительным или манометрическим и именно его измеряют, например, при проверке давления в автомобильных шинах. Измерительные приборы часто, хотя и не всегда, показывают именно относительное давление.

Атмосферное давление

Атмосферное давление — это давление воздуха в данном месте. Обычно оно обозначает давление столба воздуха на единицу площади поверхности. Изменение в атмосферном давлении влияет на погоду и температуру воздуха. Люди и животные страдают от сильных перепадов давления. Пониженное давление вызывает у людей и животных проблемы разной степени тяжести, от психического и физического дискомфорта до заболеваний с летальным исходом. По этой причине, в кабинах самолетов поддерживается давление выше атмосферного на данной высоте, потому что атмосферное давление на крейсерской высоте полета слишком низкое.

Анероид содержит датчик — цилиндрическую гофрированную коробку (сильфон), связанную со стрелкой, которая поворачивается при повышении или понижении давления и, соответственно, сжатия или расширения сильфона

Атмосферное давление понижается с высотой. Люди и животные, живущие высоко в горах, например в Гималаях, адаптируются к таким условиям. Путешественники, напротив, должны принять необходимые меры предосторожности, чтобы не заболеть из-за того, что организм не привык к такому низкому давлению. Альпинисты, например, могут заболеть высотной болезнью, связанной с недостатком кислорода в крови и кислородным голоданием организма. Это заболевание особенно опасно, если находиться в горах длительное время. Обострение высотной болезни ведет к серьезным осложнениям, таким как острая горная болезнь, высокогорный отек легких, высокогорный отек головного мозга и острейшая форма горной болезни. Опасность высотной и горной болезней начинается на высоте 2400 метров над уровнем моря. Во избежание высотной болезни доктора советуют не употреблять депрессанты, такие как алкоголь и снотворное, пить много жидкости, и подниматься на высоту постепенно, например, пешком, а не на транспорте. Также полезно есть большое количество углеводов, и хорошо отдыхать, особенно если подъем в гору произошел быстро. Эти меры позволят организму привыкнуть к кислородной недостаточности, вызванной низким атмосферным давлением. Если следовать этим рекомендациям, то организму сможет вырабатывать больше красных кровяных телец для транспортировки кислорода к мозгу и внутренним органам. Для этого организм увеличат пульс и частоту дыхания.

Первая медицинская помощь в таких случаях оказывается немедленно. Важно переместить больного на более низкую высоту, где атмосферное давление выше, желательно на высоту ниже, чем 2400 метров над уровнем моря. Также используются лекарства и портативные гипербарические камеры. Это легкие переносные камеры, в которых можно повысить давление с помощью ножного насоса. Больного горной болезнью кладут в такую камеру, в которой поддерживается давление, соответствующее более низкой высоте над уровнем моря. Такая камера используется только для оказания первой медицинской помощи, после чего больного необходимо спустить ниже.

Некоторые спортсмены используют низкое давление, чтобы улучшить кровообращение. Обычно для этого тренировки проходят в нормальных условиях, а спят эти спортсмены в среде с низким давлением. Таким образом, их организм привыкает к высокогорным условиям и начинает вырабатывать больше красных кровяных телец, что, в свою очередь, повышает количество кислорода в крови, и позволяет достичь более высоких результатов в спорте. Для этого выпускаются специальные палатки, давление в которых регулируются. Некоторые спортсмены даже изменяют давление во всей спальне, но герметизация спальни — дорогостоящий процесс.

Многоразовый транспортный космический корабль НАСА «Атлантис» в экспозиции Космического центра имени Кеннеди.

Пилотам и космонавтам приходится работать в среде с низким давлением, поэтому они работают в скафандрах, позволяющих компенсировать низкое давление окружающей среды. Космические скафандры полностью защищают человека от окружающей среды. Их используют в космосе. Высотно-компенсационные костюмы используют пилоты на больших высотах — они помогают пилоту дышать и противодействуют низкому барометрическому давлению.

Гидростатическое давление

Гидростатическое давление — это давление жидкости, вызванное силой тяжести. Это явление играет огромную роль не только в технике и физике, но также и в медицине. Например, кровяное давление — это гидростатическое давление крови на стенки кровеносных сосудов. Кровяное давление — это давление в артериях. Оно представлено двумя величинами: систолическим, или наибольшим давлением, и диастолическим, или наименьшим давлением во время сердцебиения. Приборы для измерения артериального давления называются сфигмоманометрами или тонометрами. За единицу артериального давления приняты миллиметры ртутного столба.

Цифровой аппарат для измерения давления, также называемый сфигмоманометром

Кружка Пифагора — занимательный сосуд, использующий гидростатическое давление, а конкретно — принцип сифона. Согласно легенде, Пифагор изобрел эту чашку, чтобы контролировать количество выпитого вина. По другим источникам эта чашка должна была контролировать количество выпитой воды во время засухи. Внутри кружки находится изогнутая П-образная трубка, спрятанная под куполом. Один конец трубки длиннее, и заканчивается отверстием в ножке кружки. Другой, более короткий конец, соединен отверстием с внутренним дном кружки, чтобы вода в чашке наполняла трубку. Принцип работы кружки схож с работой современного туалетного бачка. Если уровень жидкости становится выше уровня трубки, жидкость перетекает во вторую половину трубки и вытекает наружу, благодаря гидростатическому давлению. Если уровень, наоборот, ниже, то кружкой можно спокойно пользоваться.

Давление в геологии

Кристалл кварца, освещенный лазерной указкой

Давление — важное понятие в геологии. Без давления невозможно формирование драгоценных камней, как природных, так и искусственных. Высокое давление и высокая температура необходимы также и для образования нефти из остатков растений и животных. В отличие от драгоценных камней, в основном образующихся в горных породах, нефть формируется на дне рек, озер, или морей. Со временем над этими остатками собирается всё больше и больше песка. Вес воды и песка давит на остатки животных и растительных организмов. Со временем этот органический материал погружается глубже и глубже в землю, достигая нескольких километров под поверхностью земли. Температура увеличивается на 25 °C с погружением на каждый километр под земной поверхностью, поэтому на глубине нескольких километров температура достигает 50–80 °C. В зависимости от температуры и перепада температур в среде формирования, вместо нефти может образоваться природный газ.

Алмазные инструменты

Природные драгоценные камни

Образование драгоценных камней не всегда одинаково, но давление — это одна из главных составных частей этого процесса. К примеру, алмазы образуются в мантии Земли, в условиях высокого давления и высокой температуры. Во время вулканических извержений алмазы перемещаются в верхние слои поверхности Земли благодаря магме. Некоторые алмазы попадают на Землю с метеоритов, и ученые считают, что они образовались на планетах, похожих на Землю.

Синтетические драгоценные камни

Производство синтетических драгоценных камней началось в 1950-х годах, и набирает популярность в последнее время. Некоторые покупатели предпочитают природные драгоценные камни, но искусственные камни становятся все более и более популярными, благодаря низкой цене и отсутствию проблем, связанных с добычей натуральных драгоценных камней. Так, многие покупатели выбирают синтетические драгоценные камни потому, что их добыча и продажа не связана с нарушением прав человека, детским трудом и финансированием войн и вооруженных конфликтов.

Одна из технологий выращивания алмазов в лабораторных условиях — метод выращивания кристаллов при высоком давлении и высокой температуре. В специальных устройствах углерод нагревают до 1000 °C и подвергают давлению около 5 гигапаскалей. Обычно в качестве кристалла-затравки используют маленький алмаз, а для углеродной основы применяют графит. Из него и растет новый алмаз. Это самый распространенный метод выращивания алмазов, особенно в качестве драгоценных камней, благодаря низкой себестоимости. Свойства алмазов, выращенных таким способом, такие же или лучше, чем свойства натуральных камней. Качество синтетических алмазов зависит от метода их выращивания. По сравнению с натуральными алмазами, которые чаще всего прозрачны, большинство искусственных алмазов окрашено.

Благодаря их твердости, алмазы широко используются на производстве. Помимо этого ценятся их высокая теплопроводность, оптические свойства и стойкость к щелочам и кислотам. Режущие инструменты часто покрывают алмазной пылью, которую также используют в абразивных веществах и материалах. Большая часть алмазов в производстве — искусственного происхождения из-за низкой цены и потому, что спрос на такие алмазы превышает возможности добывать их в природе.

Некоторые компании предлагают услуги по созданию мемориальных алмазов из праха усопших. Для этого после кремации прах очищается, пока не получится углерод, и затем на его основе выращивают алмаз. Изготовители рекламируют эти алмазы как память об ушедших, и их услуги пользуются популярностью, особенно в странах с большим процентом материально обеспеченных граждан, например в США и Японии.

Метод выращивания кристаллов при высоком давлении и высокой температуре

Метод выращивания кристаллов при высоком давлении и высокой температуре в основном используется для синтеза алмазов, но с недавнего времени этот метод помогает усовершенствовать натуральные алмазы или изменить их цвет. Для искусственного выращивания алмазов используют разные прессы. Самый дорогой в обслуживании и самый сложный из них — это пресс кубического типа. Он используется в основном для улучшения или изменения цвета натуральных алмазов. Алмазы растут в прессе со скоростью примерно 0,5 карата в сутки.

Литература

Автор статьи: Kateryna Yuri

Unit Converter articles were edited and illustrated by Анатолий Золотков

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