A pyroclastic flow is a fast-moving current of hot gas and volcanic matter that moves away from a volcano about 100 km/h on average but is capable of reaching speeds up to 700 km/h. The gases can reach temperatures of about 1,000 °C. Pyroclastic flows are a devastating result of certain explosive eruptions, their speed depends upon the density of the current, the volcanic output rate, the gradient of the slope. The word pyroclast is derived from the Greek πῦρ, meaning "fire", κλαστός, meaning "broken in pieces". A name for pyroclastic flows which glow red in the dark is nuée ardente. Pyroclastic flows that contain a much higher proportion of gas to rock are known as "fully dilute pyroclastic density currents" or pyroclastic surges; the lower density sometimes allows them to flow over higher topographic features or water such as ridges, hills and seas. They may contain steam and rock at less than 250 °C. Cold pyroclastic surges can occur when the eruption is from a vent under the sea. Fronts of some pyroclastic density currents are dilute.
A pyroclastic flow is a type of gravity current. There are several mechanisms that can produce a pyroclastic flow: Fountain collapse of an eruption column from a Plinian eruption. In such an eruption, the material forcefully ejected from the vent heats the surrounding air and the turbulent mixture rises, through convection, for many kilometers. If the erupted jet is unable to heat the surrounding air sufficiently, convection currents will not be strong enough to carry the plume upwards and it falls, flowing down the flanks of the volcano. Fountain collapse of an eruption column associated with a Vulcanian eruption; the gas and projectiles create a cloud, denser than the surrounding air and becomes a pyroclastic flow. Frothing at the mouth of the vent during degassing of the erupted lava; this can lead to the production of a rock called ignimbrite. This occurred during the eruption of Novarupta in 1912. Gravitational collapse of a lava dome or spine, with subsequent avalanches and flows down a steep slope.
The directional blast when part of a volcano explodes. As distance from the volcano increases, this transforms into a gravity-driven current; the volumes range from a few hundred cubic meters to more than 1,000 cubic kilometres. The larger ones can travel for hundreds of kilometres, although none on that scale have occurred for several hundred thousand years. Most pyroclastic flows are around travel for several kilometres. Flows consist of two parts: the basal flow hugs the ground and contains larger, coarse boulders and rock fragments, while an hot ash plume lofts above it because of the turbulence between the flow and the overlying air and heating cold atmospheric air causing expansion and convection; the kinetic energy of the moving cloud will flatten buildings in its path. The hot gases and high speed make them lethal, as they will incinerate living organisms instantaneously: The cities of Pompeii and Herculaneum, for example, were engulfed by pyroclastic surges on August 24, 79 AD with many lives lost.
The 1902 eruption of Mount Pelée destroyed the Martinique town of St. Pierre. Despite signs of impending eruption, the government deemed St. Pierre safe due to hills and valleys between it and the volcano, but the pyroclastic flow charred the entirety of the city, killing all but two of its 30,000 residents. A pyroclastic surge killed volcanologists Harry Glicken and Katia and Maurice Krafft and 40 other people on Mount Unzen, in Japan, on June 3, 1991; the surge started as a pyroclastic flow and the more energised surge climbed a spur on which the Kraffts and the others were standing. On 25 June, 1997 a pyroclastic flow travelled down Mosquito Ghaut on the Caribbean island of Montserrat. A large energized pyroclastic surge developed; this flow could not be restrained by the Ghaut and spilled out of it, killing 19 people who were in the Streatham village area. Several others in the area suffered severe burns. Testimonial evidence from the 1883 eruption of Krakatoa, supported by experimental evidence, shows that pyroclastic flows can cross significant bodies of water.
However, that might be a pyroclastic surge, not flow, because the density of a gravity current means it cannot move across the surface of water. One flow reached the Sumatran coast as much as 48 km away. A 2006 BBC documentary film, Ten Things You Didn't Know About Volcanoes, demonstrated tests by a research team at Kiel University, Germany, of pyroclastic flows moving over water; when the reconstructed pyroclastic flow hit the water, two things happened
In 3D computer graphics, 3D modeling is the process of developing a mathematical representation of any surface of an object in three dimensions via specialized software. The product is called a 3D model. Someone who works with 3D models may be referred to as a 3D artist, it can be displayed as a two-dimensional image through a process called 3D rendering or used in a computer simulation of physical phenomena. The model can be physically created using 3D printing devices. Models may be created manually; the manual modeling process of preparing geometric data for 3D computer graphics is similar to plastic arts such as sculpting. 3D modeling software is a class of 3D computer graphics. Individual programs of this class are called modeling modelers. Three-dimensional models represent a physical body using a collection of points in 3D space, connected by various geometric entities such as triangles, curved surfaces, etc. Being a collection of data, 3D models scanned, their surfaces may be further defined with texture mapping.
3D models are used anywhere in 3D graphics and CAD. Their use predates the widespread use of 3D graphics on personal computers. Many computer games used pre-rendered images of 3D models as sprites before computers could render them in real-time; the designer can see the model in various directions and views, this can help the designer see if the object is created as intended to compared to their original vision. Seeing the design this way can help the designer/company figure out changes or improvements needed to the product. Today, 3D models are used in a wide variety of fields; the medical industry uses detailed models of organs. The movie industry uses them as objects for animated and real-life motion pictures; the video game industry uses them as assets for video games. The science sector uses them as detailed models of chemical compounds; the architecture industry uses them to demonstrate proposed buildings and landscapes in lieu of traditional, physical architectural models. The engineering community uses them as designs of new devices and structures as well as a host of other uses.
In recent decades the earth science community has started to construct 3D geological models as a standard practice. 3D models can be the basis for physical devices that are built with 3D printers or CNC machines. All 3D models can be divided into two categories. Solid – These models define the volume of the object they represent. Solid models are used for engineering and medical simulations, are built with constructive solid geometry Shell/boundary – these models represent the surface, e.g. the boundary of the object, not its volume. All visual models used in games and film are shell models. Solid and shell modeling can create functionally identical objects. Differences between them are variations in the way they are created and edited and conventions of use in various fields and differences in types of approximations between the model and reality. Shell models must be manifold to be meaningful as a real object. Polygonal meshes are by far the most common representation. Level sets are a useful representation for deforming surfaces which undergo many topological changes such as fluids.
The process of transforming representations of objects, such as the middle point coordinate of a sphere and a point on its circumference into a polygon representation of a sphere, is called tessellation. This step is used in polygon-based rendering, where objects are broken down from abstract representations such as spheres, cones etc. to so-called meshes, which are nets of interconnected triangles. Meshes of triangles are popular. Polygon representations are not used in all rendering techniques, in these cases the tessellation step is not included in the transition from abstract representation to rendered scene. There are three popular ways to represent a model: Polygonal modeling – Points in 3D space, called vertices, are connected by line segments to form a polygon mesh; the vast majority of 3D models today are built as textured polygonal models, because they are flexible and because computers can render them so quickly. However, polygons can only approximate curved surfaces using many polygons.
Curve modeling – Surfaces are defined by curves, which are influenced by weighted control points. The curve follows the points. Increasing the weight for a point will pull the curve closer to that point. Curve types include nonuniform rational B-spline, splines and geometric primitives Digital sculpting – Still a new method of modeling, 3D sculpting has become popular in the few years it has been around. There are three types of digital sculpting: Displacement, the most used among applications at this moment, uses a dense model and stores new locations for the vertex positions through use of an image map that stores the adjusted locations. Volumetric, loosely based on voxels, has similar capabilities as displacement but does not suffer from polygon stretching when there are not enough polygons in a region to achieve a deformation. Dynamic te
Berenice II of Egypt
Berenice II was a ruling queen of Cyrene by birth, a queen and co-regent of Egypt by marriage to her cousin Ptolemy III Euergetes, the third ruler of the Ptolemaic dynasty of Egypt. She was the daughter of Magas of Cyrene and Queen Apama II, she was the granddaughter of Berenice I. In 249 BC, her father died, making Berenice ruling queen of Cyrene. Soon after her father died, Berenice was married to a Macedonian prince. Berenice had no children with Demetrius. After Demetrius came to Cyrene, he became the lover of Apama. In a dramatic event, Berenice had him killed in Apama's bedroom. Berenice stood at the door and instructed the hired assassins not to hurt her mother while she attempted to protect her mother's lover. Apama lived on afterward. Although there were many plots to assassinate her, all hired assassins became fearful of her "exceptional courage." After the death of Demetrius, Berenice married Ptolemy III. Berenice is said to have participated in the Nemean Games and to have competed in Olympic games at some unknown date.
Berenice was accustomed to fighting from horseback. According to Hyginus's Astronomica, he tells of when Berenice's father Magas, king of Cyrene in modern-day Libya, his troops were routed in battle, Berenice mounted a horse, rallied the remaining forces, killed many of the enemy, drove the rest to retreat. Soon after her second husband's death in 221 BC, she was murdered at the instigation of her son, Ptolemy IV, with whom she was associated in the government. A decree "issued delineating the cult for the newly deified queen Berenike II…specified that men and women singers were to sing all day in front of the statue of Berenike." With Ptolemy III she had the following children: Arsinoe III, born in c. 246/245 BC. She married her brother Ptolemy IV Ptolemy IV Philopator, born c. 244 BC Possibly Lysimachus. The name of the son is not known, but he is said to have been born in c. 243 BC. Alexander, born in c. 242 BC Magas, born in c. 241 BC. Scalded to death in his bath by Theogos or Theodotus, at the orders of Ptolemy IV.
Berenice born in c. 239 BC and died a year later. During her second husband's absence on an expedition to Syria, she dedicated locks of her hair to Aphrodite for his safe return and victory in the Third Syrian War, placed the offering in the temple of the goddess at Zephyrium. By some unknown means, the hair offering disappeared when Ptolemy returned to Egypt. Conon of Samos explained the phenomenon in courtly phrase, saying that the hair had been carried to the heavens and placed among the stars; the name Coma Berenices or Berenice's hair, applied to a constellation, commemorates this incident. This made the locks of Berenice the only war trophy in Greco-Roman sky. Callimachus celebrated the transformation in a poem, of which only a few lines remain, but there is a fine translation of them by Catullus. Neoclassical painters illustrated this theme abundantly; the city of Euesperides was received her name, Berenice. The asteroid 653 Berenike, discovered in 1907 is named after Queen Berenice. Bevan, E.
R. The House of Ptolemy, Methuen Publishing, London, 1927 - Chapter 3, "The Second Ptolemy, "Philadelphus"
Must is freshly crushed fruit juice that contains the skins and stems of the fruit. The solid portion of the must is called pomace and makes up 7–23% of the total weight of the must. Making must is the first step in winemaking; because of its high glucose content between 10 and 15%, must is used as a sweetener in a variety of cuisines. Unlike commercially sold grape juice, filtered and pasteurized, must is thick with particulate matter and comes in various shades of brown and purple; the length of time the pomace stays in the juice is critical for the final character of the wine. When the winemaker judges the time to be right, the juice is drained off the pomace, pressed to extract the juice retained by the matrix. Yeast is added to the juice to begin the fermentation, while the pomace is returned to the vineyard or orchard for use as fertilizer. A portion of selected unfermented must may be kept as Süssreserve, to be added as a sweetening component before bottling; some winemakers create a second batch of wine from the used pomace by adding a quantity of water equivalent to the juice removed, letting the mixture sit for 24 hours, draining off the liquid.
This wine may be used as a drink for the employees of the winemaker or as a basis for some pomace brandies. Grappa, must by law be produced only from the pomace solids, with no water added. Selected bacterial colonies or the lenta in superficie or lenta a truciolo methods are used for acetification, there is a maturation phase. Both the acetification and the maturation take place in precious sessile oak, oak and juniper barrels. After a minimum maturation period of 60 days, a group of expert technicians will test the resulting product analytically and organoleptically; the must is an essential ingredient for the production of Traditional Balsamic Vinegar, the special aged vinegar from the Emilia-Romana region of Italy, protected under the European Protected Designated Origin system. This term is used by meadmakers for the unfermented honey-water mixture that becomes mead; the analogous term in beer brewing is wort. In ancient Greece, must condensed by boiling was called siraion and was used as a sweetener in the kitchen in various recipes.
From the Greeks, the Romans in ancient Rome used the condensed must in cooking, as a sweetener. Must was boiled in lead or bronze kettles into a milder concentrate called defrutum or a stronger concentrate called sapa, it was used as a souring agent and preservative in fruit dishes. Reduced must is used in Greek, other Balkan countries and Middle Eastern cookery as a syrup known as petimezi, pekmez or dibis. In Greece, petimezi is a basic ingredient for a must-custard known as moustalevria, a sweet-meal known as soutzoukos, churchkhela; the Moustokoúloura, or "must cookies" are popular Greek cookies, which are based on a sweet dough made by kneading flour, olive oil and must. They are made in various shapes and sizes, they are dark brown in color because of the must and the spice in them. In the wine making areas of South Africa must is used to make a sweet bun known as Mosbolletjies; the term petimezi is a Hellenized word of the Armenian/Trebizond term petmez. Petmez was a type of syrup, made with berries of the White Mulberry tree.
Geochemist Jerome Nriagu published an article in the New England Journal of Medicine in 1983 hypothesizing that defrutum and sapa may have contained enough lead acetate to be toxic to those who consumed them regularly. In Roman Catholic Eucharistic liturgy, must may be substituted for sacramental wine, on condition that the ordinary has granted permission for the benefit of a priest or lay person who should not because of alcoholism, ingest wine. Official Roman Catholic documents define must as "grape juice, either fresh or preserved by methods that suspend its fermentation without altering its nature", it excludes pasteurized grape juice; this teaching goes back at least to Pope Julius I, quoted in Thomas Aquinas's Summa Theologica as having declared that in case of necessity, but only juice pressed from a grape could be used. Aquinas himself declared that it is forbidden to offer fresh must in the chalice, because this is unbecoming owing to the impurity of the must. Aquinas himself declared: Must has the species of wine, for its sweetness indicates fermentation, "the result of its natural heat".
It is forbidden to offer must in the chalice, as soon as it has been squeezed from the grape, since this is unbecoming owing to the impurity of the must. But in case of necessity it may be done: for it is said by the same Pope Julius, in the passage quoted in the argument: "If necessary, let the grape be pressed into the chalice." The latest document from the Congregation for the Doctrine of the Faith on the matter, issued on 24 July 2003, gave the following norms, which simplify those in force: The Ordinary is competent to give permission for an individual priest or layperson to use mustum for the celebration of the Eucharist. Permission can be gra
Pompeii was an ancient Roman city near modern Naples in the Campania region of Italy, in the territory of the comune of Pompei. Pompeii, along with Herculaneum and many villas in the surrounding area, was buried under 4 to 6 m of volcanic ash and pumice in the eruption of Mount Vesuvius in AD 79. Volcanic ash buried inhabitants who did not escape the lethal effects of the earthquake and eruption. Preserved under the ash, the excavated city offers a unique snapshot of Roman life, frozen at the moment it was buried and providing an extraordinarily detailed insight into the everyday life of its inhabitants. Organic remains, including wooden objects and human bodies, were entombed in the ash and decayed away, making natural molds; the numerous graffiti carved on the walls and inside rooms provides a wealth of examples of the lost Vulgar Latin spoken colloquially, contrasting with the formal language of the classical writers. Pompeii is a UNESCO World Heritage Site status and is one of the most popular tourist attractions in Italy, with 2.5 million visitors every year.
Excavations recommenced in several unexplored areas of the city, in 2018 new discoveries were reported. Pompeii in Latin is a second declension plural noun. According to Theodor Kraus, "The root of the word Pompeii would appear to be the Oscan word for the number five, which suggests that either the community consisted of five hamlets or it was settled by a family group." The ruins of Pompeii are located near the modern town of Pompei and about 8 km away from Mount Vesuvius. It stands on a spur about 40 m above sea level formed by an ancient lava flow to the north of the mouth of the Sarno River. Three sheets of sediment from large landslides lie on top of the lava triggered by extended rainfall. Today, Pompeii is some distance inland, it covered a total of 64 to 67 hectares and was home to 11,000 to 11,500 people, on the basis of household counts. The first stable settlements on the site date back to the 8th century BC when the Oscans, a people of central Italy, founded five villages in the area.
With the arrival of the Greeks in Campania from around 740 BC Pompeii entered into the orbit of the Hellenic people and the most important building of this period is the Doric Temple, built not near the centre, but in a more isolated position in what would become the Triangular Forum, as the Greeks wanted to control just the streets and the port. At the same time the cult of Apollo was introduced. Greek and Phoenician sailors used the location as a safe port. Around the 6th century BC, it merged into a single community on the important crossroad between Cumae and Stabiae and was surrounded by a tufa city wall, it began to flourish and the first maritime trade started with the construction of a small port near the mouth of the river. The earliest settlement was focussed in regions VII and VIII of the town as identified from stratigraphy below the Samnite and Roman buildings. 524 BC saw the arrival and settlement of the Etruscans in the area including Pompeii, finding in the river Sarno a communication route between the sea and the interior.
To the Greeks, the Etruscans did not conquer the city militarily, but controlled it and Pompeii enjoyed a sort of autonomy. Pompeii became a member of the Etruscan League of cities. Recent excavations have shown the presence of a 6th-century BC necropolis. Under the Etruscans a primitive forum or simple market square was built, as well as the temple of Apollo, in both of which objects including fragments of bucchero were found by Maiuri. Several houses were built with typical of this people; the city wall was strengthened in the early 5th century BC with two façades of thin, vertically set, slabs of Sarno limestone some 4 m apart filled with earth. In 474 BC the Greek city of Cumae, allied with Syracuse, conquered the Etruscans definitively at the Battle of Cumae and gained control of the area; the period between about 450–375 BC witnessed large areas of the city being abandoned while important sanctuaries such as the Temple of Apollo show a sudden lack of votive material remains. The Samnites, people coming from the areas of Abruzzo and Molise, allies of the Romans, conquered Greek Cumae between 423 and 420 BC and it is that in advance, all the surrounding territory, including Pompeii, was conquered around 424 BC.
The new rulers imposed their architecture and enlarged the town. From 343 BC the first Roman army entered the Campanian plain bringing with it the customs and traditions of Rome and in the Roman war against the Latins the Samnites were faithful to Rome. Pompeii, although governed by the Samnites, entered in effect in the Roman orbit, to which it remained faithful during the third Samnite war and in the war against Pyrrhus; the city walls were reinforced in Sarno stone in the early 3rd century BC. It formed the basis for the visible walls with an outer wall of rectangular limestone blocks as an enormous terrace wall supporting a large agger, or earth embankment, behind it. After the Samnite Wars from 290 BC, Pompeii was forced to accept the status of socii of Rome, however and administrative autonomy. From the outbreak of the Second Punic War in which Pompeii remained faithful to Rome, an addit
Boscoreale is an Italian comune and town in the Metropolitan City of Naples, with a population of 27,457 in 2011. Located in the Parco Nazionale del Vesuvio, under the slopes of Mount Vesuvius, it is known for the fruit and vineyards of Lacryma Christi del Vesuvio. There is a fine Vesuvian lava stone production; the neighbourhood of Monte Bursaccio, overcome by the eruption of Vesuvius in 79 AD that obliterated and preserved its better-known neighbours and Herculaneum, is famous for the frescoes of its aristocratic villas, excavated before World War I. A hoard of Roman silver and coins, hurriedly stashed in a cistern for protection at the time of the eruption was recovered in Boscoreale in 1895, divided among several museums, including the Louvre and the British Museum. Boscoreale, about a kilometre north of Pompeii of which it was an expansive, more rural outlying suburb, was notable in antiquity for having numerous aristocratic country villas and was preserved as a hunting park - hence its name, meaning "Royal Grove" - by the kings of Naples.
The villa of P. Fannius Synistor was built and decorated shortly after mid-first century BC; the quality of its frescoes seems to have preserved them from changes in fashion, before the villa was entombed in the eruption. The Antiquarium of Boscoreale was founded in 1991 by the Soprintendenza archeologica di Pompei thanks to the finds from Pompeii, Oplontis, Stabiae and Boscoreale and to a didactic apparatus; the neighbouring Boscotrecase yielded some elite works of art to excavators at the same time, in particular at the Villa of Agrippa Postumus known as the Imperial Villa or the Villa of Augusta. The municipality is part of Naples metropolitan area, borders with Boscotrecase, Pompei, Scafati and Torre Annunziata, it counts the hamlets of Cangiani, Marra and Pellegrini. Boscoreale Treasure Baratte, François. Le Trésor d'orfèvrerie romaine de Boscoreale. Paris: Musée de Louvre. ISBN 2-7118-2048-3. Official website Boscoreale on comuni-italiani.it Soprintendenza Archeologica di Pompeii: the main rustic villas Herculaneum/Pompeii/Stabiae website AD79 Year of Destruction Website Frescos from the house of P. Fannius Synistor, Boscoreale Fresco section from the villa of Fannius Sinistor, Boscoreale (Archaeological Museum Naples Cubiculum from the house of P. Fannius Synistor, Boscoreale Period Rooms in the Metropolitan Museum of Art Boscoreale treasure
Axonometric projection is a type of orthographic projection used for creating a pictorial drawing of an object, where the lines of sight are perpendicular to the plane of projection, the object is rotated around one or more of its axes to reveal multiple sides. "Axonometry" means "to measure along axes". In German literature, axonometry is based on Pohlke's theorem, so that the scope of axonometric projection encompasses every type of parallel projection, including not only oblique projection, but orthographic projection and therefore multiview projection. However, outside of German literature, the term "axonometric" is used to make an explicit distinction from multiview projection, because axonometric projection allows for the depiction of more than one "side" of an object, whereas a multiview projection allows for the depiction of only one "side" of an object: A multiview projection depicts an object from one of six primary views; because multiview projections are a fundamental facet of technical illustration, a depiction that results from another type of projection is called an "auxiliary" view.
In contrast, an axonometric projection may depict an object such that none of the principal axes of the object is perpendicular to the projection plane, thus more than one "side" of an object may be represented simultaneously. When it is possible to depict more than one side of an object, it may be said that the object is being viewed from a "skew" angle. Furthermore, in English literature, the term "axonometric projection" implies an orthographic projection, such as an isometric projection. With an axonometric projection, the scale of an object does not depend on its location along any particular axis; this distortion, the direct result of a presence or absence of foreshortening, is evident if the object is composed of rectangular features. Despite this limitation, axonometric projection can be useful for purposes of illustration because it allows for relaying precise measurements; the three types of axonometric projection are isometric projection, dimetric projection, trimetric projection, depending on the exact angle at which the view deviates from the orthogonal.
In axonometric drawing, as in other types of pictorials, one axis of space is shown as the vertical. In isometric projection, the most used form of axonometric projection in engineering drawing, the direction of viewing is such that the three axes of space appear foreshortened, there is a common angle of 120° between them; as the distortion caused by foreshortening is uniform, the proportionality between lengths is preserved, the axes share a common scale. Another advantage is that 120° angles are constructed using only a compass and straightedge. In dimetric projection, the direction of viewing is such that two of the three axes of space appear foreshortened, of which the attendant scale and angles of presentation are determined according to the angle of viewing. Dimensional approximations are common in dimetric drawings. In trimetric projection, the direction of viewing is such that all of the three axes of space appear unequally foreshortened; the scale along each of the three axes and the angles among them are determined separately as dictated by the angle of viewing.
Dimensional approximations in trimetric drawings are common, trimetric perspective is used in technical drawings. The concept of isometry had existed in a rough empirical form for centuries, well before Professor William Farish of Cambridge University was the first to provide detailed rules for isometric drawing. Farish published his ideas in the 1822 paper "On Isometrical Perspective", in which he recognized the "need for accurate technical working drawings free of optical distortion; this would lead him to formulate isometry. Isometry means "equal measures" because the same scale is used for height and depth". From the middle of the 19th century, according to Jan Krikke isometry became an "invaluable tool for engineers, soon thereafter axonometry and isometry were incorporated in the curriculum of architectural training courses in Europe and the U. S; the popular acceptance of axonometry came in the 1920s, when modernist architects from the Bauhaus and De Stijl embraced it". De Stijl architects like Theo van Doesburg used axonometry for their architectural designs, which caused a sensation when exhibited in Paris in 1923".
Since the 1920s axonometry, or parallel perspective, has provided an important graphic technique for artists and engineers. Like linear perspective, axonometry helps depict three-dimensional space on a two-dimensional picture plane, it comes as a standard feature of CAD systems and other visual computing tools. According to Jan Krikke, "axonometry originated in China, its function in Chinese art was similar to linear perspective in European art. Axonometry, the pic