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Frescos
Fresco (plural ''frescos'' or ''frescoes'') is a technique of mural painting executed upon freshly laid ("wet") lime plaster. Water is used as the vehicle for the dry-powder pigment to merge with the plaster, and with the setting of the plaster, the painting becomes an integral part of the wall. The word ''fresco'' ( it, affresco) is derived from the Italian adjective ''fresco'' meaning "fresh", and may thus be contrasted with fresco-secco or secco mural painting techniques, which are applied to dried plaster, to supplement painting in fresco. The fresco technique has been employed since antiquity and is closely associated with Italian Renaissance painting. The word ''fresco'' is commonly and inaccurately used in English to refer to any wall painting regardless of the plaster technology or binding medium. This, in part, contributes to a misconception that the most geographically and temporally common wall painting technology was the painting into wet lime plaster. Even in appare ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lime Kiln
A lime kiln is a kiln used for the calcination of limestone ( calcium carbonate) to produce the form of lime called quicklime (calcium oxide). The chemical equation for this reaction is : CaCO3 + heat → CaO + CO2 This reaction can take place at anywhere above 840 °C (1544 °F), but is generally considered to occur at 900 °C(1655 °F) (at which temperature the partial pressure of CO2 is 1 atmosphere), but a temperature around 1000 °C (1832 °F) (at which temperature the partial pressure of CO2 is 3.8 atmospheres) is usually used to make the reaction proceed quickly.Parkes, G.D. and Mellor, J.W. (1939). ''Mellor's Modern Inorganic Chemistry'' London: Longmans, Green and Co. Excessive temperature is avoided because it produces unreactive, "dead-burned" lime. Slaked lime (calcium hydroxide) can be formed by mixing quicklime with water. Early lime use Because it is so readily made by heating limestone, lime must have been known from the earli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egg (food)
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especially chickens. Eggs of other birds, including ostriches and other ratites, are eaten regularly but much less commonly than those of chickens. People may also eat the eggs of reptiles, amphibians, and fish. Fish eggs consumed as food are known as roe or caviar. Bird and reptile eggs consist of a protective eggshell, albumen ( egg white), and vitellus ( egg yolk), contained within various thin membranes. Egg yolks and whole eggs store significant amounts of protein and choline, and are widely used in cookery. Due to their protein content, the United States Department of Agriculture formerly categorized eggs as ''Meats'' within the Food Guide Pyramid (now MyPlate). Despite the nutritional value of eggs, there are some potential healt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giotto Di Bondone - No
Giotto di Bondone (; – January 8, 1337), known mononymously as Giotto ( , ) and Latinised as Giottus, was an Italian painter and architect from Florence during the Late Middle Ages. He worked during the Gothic/Proto-Renaissance period. Giotto's contemporary, the banker and chronicler Giovanni Villani, wrote that Giotto was "the most sovereign master of painting in his time, who drew all his figures and their postures according to nature" and of his publicly recognized "talent and excellence".Bartlett, Kenneth R. (1992). ''The Civilization of the Italian Renaissance''. Toronto: D.C. Heath and Company. (Paperback). p. 37. Giorgio Vasari described Giotto as making a decisive break with the prevalent Byzantine style and as initiating "the great art of painting as we know it today, introducing the technique of drawing accurately from life, which had been neglected for more than two hundred years".Giorgio Vasari, ''Lives of the Artists'', trans. George Bull, Penguin Classics, (19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assisi
Assisi (, also , ; from la, Asisium) is a town and '' comune'' of Italy in the Province of Perugia in the Umbria region, on the western flank of Monte Subasio. It is generally regarded as the birthplace of the Latin poet Propertius, born around 50–45 BC. It is the birthplace of St. Francis, who founded the Franciscan religious order in the town in 1208, and St. Clare (''Chiara d'Offreducci''), who with St. Francis founded the Poor Sisters, which later became the Order of Poor Clares after her death. The 19th-century Saint Gabriel of Our Lady of Sorrows was also born in Assisi. History Around 1000 BC a wave of immigrants settled in the upper Tiber valley as far as the Adriatic Sea, and also in the neighbourhood of Assisi. These were the Umbrians, living in small fortified settlements on high ground. From 450 BC these settlements were gradually taken over by the Etruscans. The Romans took control of central Italy after the Battle of Sentinum in 295 BC. They built the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basilica Of San Francesco D'Assisi
The Basilica of Saint Francis of Assisi ( it, Basilica di San Francesco d'Assisi; la, Basilica Sancti Francisci Assisiensis) is the mother church of the Roman Catholic Order of Friars Minor Conventual in Assisi, a town in the Umbria region in central Italy, where Saint Francis was born and died. It is a Papal minor basilica and one of the most important places of Christian pilgrimage in Italy. With its accompanying friary, Sacro Convento, the basilica is a distinctive landmark to those approaching Assisi. It has been a UNESCO World Heritage Site since 2000. The basilica, which was begun in 1228, is built into the side of a hill and comprises two churches (known as the Upper Church and the Lower Church) and a crypt, where the remains of the saint are interred. The interior of the Upper Church is an important early example of the Gothic style in Italy. The Upper and Lower Churches are decorated with frescoes by numerous late medieval painters from the Roman and Tuscan schools, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
School Of Athens
A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compulsory. In these systems, students progress through a series of schools. The names for these schools vary by country (discussed in the '' Regional terms'' section below) but generally include primary school for young children and secondary school for teenagers who have completed primary education. An institution where higher education is taught is commonly called a university college or university. In addition to these core schools, students in a given country may also attend schools before and after primary (elementary in the U.S.) and secondary (middle school in the U.S.) education. Kindergarten or preschool provide some schooling to very young children (typically ages 3–5). University, vocational school, college or seminary may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonatation
Carbonatation is a chemical reaction in which calcium hydroxide reacts with carbon dioxide and forms insoluble calcium carbonate: :Ca(OH)2CO2->CaCO3H_2O The process of forming a carbonate is sometimes referred to as "carbonation", although this term usually refers to the process of dissolving carbon dioxide in water. Concrete Carbonatation is a slow process that occurs in concrete where lime (CaO, or Ca(OH)2( aq)) in the cement reacts with carbon dioxide (CO2) from the air and forms calcium carbonate. The water in the pores of Portland cement concrete is normally alkaline with a pH in the range of 12.5 to 13.5. This highly alkaline environment is one in which the steel rebar is passivated and is protected from corrosion. According to the Pourbaix diagram for iron, the metal is passive when the pH is above 9.5.{{cite web , url=http://www.corrosion-doctors.org/Thermo/ironE-pH.htm , title=Pourbaix diagram of iron , publisher=Corrosion-doctors.org , date= , accessdate= ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinopia
Sinopia (also known as sinoper, named after the now Turkish city Sinop) is a dark reddish-brown natural earth pigment, whose reddish colour comes from hematite, a dehydrated form of iron oxide. It was widely used in Classical Antiquity and the Middle Ages for painting, and during the Renaissance it was often used on the rough initial layer of plaster for the underdrawing for a fresco. The word came to be used both for the pigment and for the preparatory drawing itself, which may be revealed when a fresco is stripped from its wall for transfer. During the Middle Ages sinopia in Latin and Italian came to mean simply a red ochre. It entered the English language as the word sinoper, meaning a red earth colour. Sinopia is a colour in various modern colour systems. Sinopia pigment From Ancient times through the Renaissance, the pigment was mined in Cappadocia, and exported to Europe through the port of Sinop, a Greek colony on the Black Sea. The pigment was valued for its quali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Hydroxide
Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed or slaked with water. It has many names including hydrated lime, caustic lime, builders' lime, slaked lime, cal, and pickling lime. Calcium hydroxide is used in many applications, including food preparation, where it has been identified as E number E526. Limewater, also called milk of lime, is the common name for a saturated solution of calcium hydroxide. Properties Calcium hydroxide is poorly soluble in water, with a retrograde solubility increasing from 0.66 g/L at 100 °C to 1.89 g/L at 0 °C. With a solubility product ''K''sp of 5.02 at 25 °C, its dissociation in water is large enough that its solutions are basic according to the following dissolution reaction: : Ca(OH)2 → Ca2+ + 2 OH− At ambient temperature, calcium hydroxide (portlandite) d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slaking (geology)
Slaking is the process in which earth materials disintegrate and crumble when exposed to moisture. The term can be applied to natural geologic formations, land modified by or for human use, or to the use of earth materials in manufacturing or industry. This process can often lead to erosion if the geologic area is not flat or vegetated. The slaking property does not necessarily have to be in the A horizon, with B horizon slaking only becoming a problem when the A horizon is disturbed or eroded away. Slaking occurs on soil aggregates and is correlated with the rate of wetting, the faster the wetting, the more slaking occurs. Preventing slaking As with most erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is d ... slaking can be prevented with re-vegetation of bare soil and limi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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