Robert Campin, now identified with the Master of Flémalle, was the first great master of Flemish and Early Netherlandish painting. Campin's identity and the attribution of the paintings in both the "Campin" and "Master of Flémalle" groupings have been a matter of controversy for decades. Campin was successful during his lifetime, thus his activities are well documented, but he did not sign or date his works, none can be securely connected with him. A corpus of work attached to the unidentified "Master of Flémalle", so named in the 19th century after three religious panels said to have come from a monastery in Flémalle, they are each assumed to be wings of triptychs or polyptychs, are the Virgin and Child with a Firescreen now in London, a panel fragment with the Thief on the Cross in Frankfurt, the Brussels version of the Mérode Altarpiece. Campin was active by 1406 as a master painter in Tournai, in today's Belgium, became that city's leading painter for 30 years, he had attained citizenship by 1410, may have studied under Jan van Eyck.
His fame had spread enough by 1419 that he led a profitable workshop. He became involved in the revolt of the Brotherhoods in the early 1420s, yet he maintained his standing and workshop until his death in 1444. The early Campin panels shows the influence of the International Gothic artists the Limbourg brothers and Melchior Broederlam, but display a more realistic observation than any earlier artists, which he achieved through innovations in the use of oil paints, he was successful in his lifetime, the recipient of a number of civic commissions. Campin taught Jacques Daret, he was a contemporary of Jan van Eyck, they met in 1427. Campin's best known work is the Mérode Altarpiece of c 1425-28. Campin first appears as settled in Tournai from the archives of 1405–6, as a free master of the guild of goldsmiths and painters, there has been a lot of speculation about his origin and birthplace, unknown, although he is sometimes listed as having been born in Valenciennes. In 1408 he had purchased the house.
In 1410 he bought into the full citizenship. Records show a large number of commissions from individuals and guilds, as well as from ecclesiastical and civic authorities. Campin purchased city bonds and invested in mortgages. Between 1423 and 1429, the city government was dominated by the guilds. Campin was the deputy dean of the guild of goldsmiths and painters in 1423/24 and 1425. In 1427 he represented the guild on the city council. After restoration of the oligarchy of full citizens, the leaders of the guild regime, including Robert Campin, were brought to court. Campin was ordered to pay the fine. Campin was married to Ysabel de Stocquain; the couple was childless. He had an affair with Laurence Polette, for which he was prosecuted in 1432 and sentenced to banishment for a year. Margaret of Burgundy, wife of the Count of Holland and sister of John the Fearless, Duke of Burgundy intervened on his behalf, this was reduced to a fine. Short time after the verdict Campin’s apprentices Rogier van der Weyden and Jacques Daret were accepted as masters into the guild of painters.
However, the dated Werl Altarpiece shows. He died in his adopted city of Tournai in 1444. Although indebted to late 14th-century manuscript illumination aesthetics, Campin displayed greater powers of realistic observation than any other painter before him, he was one of the first to experiment with the use of oil-based colours, in lieu of egg-based tempera, to achieve the brilliance of color typical for this period. Campin used the new technique to convey strong, rounded characters by modelling light and shade in compositions of complex perspectives, it remains a matter of debate how far the complex symbolism, accepted as existing in the work of Van Eyck exists in the work of Campin. Art historians have long been keen to trace the beginnings of the Northern Renaissance - with far less evidence to go on than in Italy. For a long time it was thought that Jan van Eyck was the first painter to make full use of the innovations apparent in manuscript illumination in panel painting. By the end of the 19th century it became clear, that Van Eyck was the contemporary of an artist who painted a number of works, including the Mérode Altarpiece.
Dated to about 1428, the altarpiece is permeated with loving attention to details and realism. Three other panels in a similar manner, supposed to come from the so-called abbey of Flémalle, are now in Frankfurt, it was argued that these works belong to one "Master of Flémalle", whose identity at that time could not be established. In the 20th century, several scholars suggested that the Master of Flémalle may be Robert Campin, documented as a master painter in Tournai from 1406; the argument turns around a paper mentioning two pupils entering his studio in 1427 - Jacques Daret and Rogelet de la Pasture. The latter was Rogier van der Weyden. A well-documented altarpiece by Daret shows striking similarities with the works of Master of Flémalle, as do early works by Rogier. Therefore, it is
The Werl Triptych
The Werl Triptych is a triptych altarpiece completed in Cologne in 1438, of which the center panel has been lost. The two remaining wings are now in the Prado in Madrid, it was long attributed to the Master of Flémalle, now believed to have been Robert Campin, although this identity is not universally accepted. Some art historians believe it may have been painted as a pastiche by either the workshop or a follower of Campin or the Master of Flémalle; the right wing depicts a seated, pious Saint Barbara, shown engrossed in her reading of a bound and gilded holy book, seated in front of a warm open fire which lights the room with a golden glow. The left wing has a donor portrait of Heinrich von Werl, who kneels in prayer in the company of John the Baptist facing the missing devotional center-panel scene, lost and unrecorded; the two extant panels are in Madrid and renowned for their complex treatment of both form. The panels became influential on other artists from the mid-15th until the early 16th century, after when Early Netherlandish painting fell out of favour until it was rediscovered in the early 19th century.
From an inscription in the left wing, the panels are known to have been commissioned by Heinrich von Werl, provincial head of Cologne during 1438. He is shown in the left wing kneeling in devotion alongside Saint John the Baptist; this panel contains a number of elements indebted to Jan van Eyck, notably the convex mirror in the midground, which as with the 1434 Arnolfini Marriage, reflects the scene back at the viewer. Although the center panel is lost with no surviving copies, inventory records or descriptions, it has been speculated that it was set in the same room occupied by Saint Barbara; this is given the abrupt end of the lines of the beams of the roof and the frames of the window, as well as the direction of the falling light. The center panel may have formed the setting for a Virgo inter Virgines. Given that there is no surviving evidence of the triptych's influence on Cologne art until the middle of the century, it was the triptych was until positioned either in private or in an inaccessible place in the church large enough to hold a number of altarpieces.
However it became influential from the mid-15th century. Of the two panels, that of Barbara, although flawed in some anatomical respects, is richer in detail and considered the superior piece; the woman in this panel can be identified as Saint Barbara from the tower visible beyond the open window to her top left. A popular saint in the Middle Ages, she was a Christian martyr believed to have lived in the 3rd century. According to hagiography, her wealthy pagan father Dioscorus, seeking to preserve her from unwelcome suitors, imprisoned her in a tower. Captive Barbara let in a priest who baptised her, an act for which she was hunted and beheaded by her father, she became a popular subject for artists of Campin's generation. Jan van Eyck left a detailed but unfinished 1437 oak panel which focuses on the complex architectural details of an imagined Gothic tower; the artist depicts Barbara imprisoned in her tower, but engrossed in her reading of a book with her back against a large open fireplace.
Her brown hair is unbound and falling to her shoulders. She is seated on a wooden bench draped with deep red velvet cushions, she wears a sumptuous green dress lined with heavy angular folds. Yet Barbara's figure is weakly rendered – her shoulders and knees are anatomically unrealistic; the panel's strength comes from her well-described clothing and the detailed objects placed around her, most of which are shaped and contrasted by the two sources of light falling on their golden and polished surfaces. The fireplace emits a warm reddish glow, which contrasts with the hard light falling from the window and the unseen middle panel to the left; the ledge of the fireplace holds a glass flask while the chimney place contains a sconce holding an extinguished candle holder. A detailed sculpture of the Trinity is shown above the fireplace; the room is from a contemporary middle-class rather than biblical setting, contains many of the same details found in the center panel of the c 1425–28 Mérode Altarpiece attributed to Robert Campin.
These include the latticed and shuttered window, the reading Virgin seated on a long bench, the tilted iris in a vase on a table to her side. Writers Peter and Linda Murray note that the treatment in the work is better arranged and far more assured in its use of perspective; the perspective from which the room is viewed is unusually steep and positions the viewer as if he is on a higher floor to the Virgin and looking down at her. It has been identified as influenced by van Eyck's Washington Annunciation painted just a few years earlier; the painting contains a number of vanishing points stretching from the lower right hand to the open window serve to emphasise the panel's depth. The steep angle of the panel from the viewer's point of view is achieved through the tilt of the bench, side board, line of the fireplace, shutters of the window. According to Walther Ingo, the dramatic angle of these elements serves to demote the figure of St Barbara to secondary importance to an examination of the anatomy of the space itself.
The donor, Heinrich von Werl, is named in the Latin inscription on the left wing, which translates as. Von Werl was a member of the Minorites order in Osnabrück, he moved to Cologne in 1430 to study at the university, where he receiv
A mouth mirror or dentist's mirror is an instrument used in dentistry. The head of the mirror is round, the most common sizes used are the No. 4 Ø and No. 5. A No. 2 is sometimes used when a smaller mirror is needed, such as when working on back teeth with a dental dam in place. The mouth mirror has a wide range of uses. Three of its most important functions are allowing indirect vision by the dentist, reflecting light onto desired surfaces, retraction of soft tissues. There exists 2 different norms of the thread; the US norm have a taper thread and is used in the United States, Canada and South Korea. Indirect vision is needed in certain locations of the mouth where visibility is difficult or impossible; the posterior surfaces of the anterior maxillary teeth is a notable area where mouth mirrors are used. Other areas of the mouth can be viewed more with the mouth mirror though it would be possible to see them if the dentist or dental hygienist adjusted their body into a poor position. Without the mouth mirror, poor body positioning would occur daily and lead to chronic postural problems of the back and neck.
There are other areas of the mouth where lighting is difficult with overhead dentists' lights. In these instances, the mouth mirror is used to reflect light onto those surfaces; this is useful if the mirror is being used for indirect vision of an obscure area. Additionally, the mouth mirror is used to retract tissues, such as the tongue or cheeks, to gain better visualization of the teeth. Dentist's mirrors are commonly used by engineers to allow vision in tight spaces and around corners in equipment, they are a common tool in optics and laser labs as well. Summit, James B. J. William Robbins, Richard S. Schwartz. "Fundamentals of Operative Dentistry: A Contemporary Approach." 2nd edition. Carol Stream, Quintessence Publishing Co, Inc, 2001. ISBN 0-86715-382-2
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, compulsory. In these systems, students progress through a series of schools; the names for these schools vary by country but include primary school for young children and secondary school for teenagers who have completed primary education. An institution where higher education is taught, is called a university college or university, but these higher education institutions are not compulsory. In addition to these core schools, students in a given country may attend schools before and after primary and secondary education. Kindergarten or pre-school provide some schooling to young children. University, vocational school, college or seminary may be available after secondary school. A school may be dedicated to one particular field, such as a school of economics or a school of dance. Alternative schools may provide nontraditional curriculum and methods.
There are non-government schools, called private schools. Private schools may be required. Other private schools can be religious, such as Christian schools, hawzas and others. Schools for adults include institutions of corporate training, military education and training and business schools. In home schooling and online schools and learning take place outside a traditional school building. Schools are organized in several different organizational models, including departmental, small learning communities, academies and schools-within-a-school; the word school derives from Greek σχολή meaning "leisure" and "that in which leisure is employed", but "a group to whom lectures were given, school". The concept of grouping students together in a centralized location for learning has existed since Classical antiquity. Formal schools have existed at least since ancient Greece, ancient Rome ancient India, ancient China; the Byzantine Empire had an established schooling system beginning at the primary level.
According to Traditions and Encounters, the founding of the primary education system began in 425 AD and "... military personnel had at least a primary education...". The sometimes efficient and large government of the Empire meant that educated citizens were a must. Although Byzantium lost much of the grandeur of Roman culture and extravagance in the process of surviving, the Empire emphasized efficiency in its war manuals; the Byzantine education system continued until the empire's collapse in 1453 AD. In Western Europe a considerable number of cathedral schools were founded during the Early Middle Ages in order to teach future clergy and administrators, with the oldest still existing, continuously operated, cathedral schools being The King's School, King's School, Rochester, St Peter's School and Thetford Grammar School. Beginning in the 5th century CE monastic schools were established throughout Western Europe, teaching both religious and secular subjects. Islam was another culture. Emphasis was put on knowledge, which required a systematic way of teaching and spreading knowledge, purpose-built structures.
At first, mosques combined both religious performance and learning activities, but by the 9th century, the madrassa was introduced, a school, built independently from the mosque, such as al-Qarawiyyin, founded in 859 CE. They were the first to make the Madrassa system a public domain under the control of the Caliph. Under the Ottomans, the towns of Bursa and Edirne became the main centers of learning; the Ottoman system of Külliye, a building complex containing a mosque, a hospital and public kitchen and dining areas, revolutionized the education system, making learning accessible to a wider public through its free meals, health care and sometimes free accommodation. In Europe, universities emerged during the 12th century. During the Middle Ages and much of the Early Modern period, the main purpose of schools was to teach the Latin language; this led to the term grammar school, which in the United States informally refers to a primary school, but in the United Kingdom means a school that selects entrants based on ability or aptitude.
Following this, the school curriculum has broadened to include literacy in the vernacular language as well as technical, artistic and practical subjects. Obligatory school attendance became common in parts of Europe during the 18th century. In Denmark-Norway, this was introduced as early as in 1739-1741, the primary end being to increase the literacy of the almue, i.e. the "regular people". Many of the earlier public schools in the United States and elsewhere were one-room schools where a single teacher taught seven grades of boys and girls in the same classroom. Beginning in the 1920s, one-room schools were consolidated into multiple classroom facilities with transportation provided by kid hacks and school buses; the use of the term school varies by country, as do the names of the various levels of education within the country
Concentrated solar power
Concentrated solar power systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight, or solar thermal energy, onto a small area. Electricity is generated when the concentrated light is converted to heat, which drives a heat engine connected to an electrical power generator or powers a thermochemical reaction. CSP had a world's total installed capacity of 4,815 MW in 2016, up from 354 MW in 2005; as of 2017, Spain accounted for half of the world's capacity, at 2,300 MW, making this country the world leader in CSP. The United States follows with 1,740 MW. Interest is notable in North Africa and the Middle East, as well as India and China; the global market has been dominated by parabolic-trough plants, which accounted for 90% of CSP plants at one point. The largest CSP projects in the world are the Ivanpah Solar Power Facility in the United States and the Mojave Solar Project in the United States. In most cases, CSP technologies cannot compete on price with photovoltaic solar panels, which have experienced huge growth in recent years due to falling prices and much smaller operating costs.
CSP needs large amount of direct solar radiation, its energy generation falls with cloud cover. This is in contrast with photovoltaics, which can produce electricity from diffuse radiation. However, the advantage of CSP over PV is that as a thermal technology, running a conventional thermal power block, a CSP plant can store the heat of solar energy in molten salts, which enables these plants to continue to generate electricity whenever it is needed, whether day or night; this makes CSP a dispatchable form of solar. This is valuable in places where there is a high penetration of PV, such as California because an evening peak is being exacerbated as PV ramps down at sunset. CSP has other uses than electricity. Researchers are investigating solar thermal reactors for the production of solar fuels, making solar a transportable form of energy in the future; these researchers use the solar heat of CSP as a catalyst for thermochemistry to break apart molecules of H2O, to create hydrogen from solar energy with no carbon emissions.
By splitting both H2O and CO2, other much-used hydrocarbons – for example, the jet fuel used to fly commercial airplanes – could be created with solar energy rather than from fossil fuels. In 2017, CSP represented less than 2% of worldwide installed capacity of solar electricity plants. However, in recent years falling prices of CSP plants are making this technology competitive with other base-load power plants using fossil and nuclear fuel in high moisture and dusty atmosphere at sea level, such as the United Arab Emirates. Base-load CSP tariff in the dry Atacama region of Chile reached below ¢5.0/kWh in 2017 auctions. A legend has it that Archimedes used a "burning glass" to concentrate sunlight on the invading Roman fleet and repel them from Syracuse. In 1973 a Greek scientist, Dr. Ioannis Sakkas, curious about whether Archimedes could have destroyed the Roman fleet in 212 BC, lined up nearly 60 Greek sailors, each holding an oblong mirror tipped to catch the sun's rays and direct them at a tar-covered plywood silhouette 49 m away.
The ship caught fire after a few minutes. In 1866, Auguste Mouchout used a parabolic trough to producе steam for the first solar steam engine; the first patent for a solar collector was obtained by the Italian Alessandro Battaglia in Genoa, Italy, in 1886. Over the following years, invеntors such as John Ericsson and Frank Shuman developed concentrating solar-powered dеvices for irrigation, refrigеration, locomоtion. In 1913 Shuman finished a 55 HP parabolic solar thermal energy station in Maadi, Egypt for irrigation; the first solar-power system using a mirror dish was built by Dr. R. H. Goddard, well known for his research on liquid-fueled rockets and wrote an article in 1929 in which he asserted that all the previous obstacles had been addressed. Professor Giovanni Francia designed and built the first concentrated-solar plant, which entered into operation in Sant'Ilario, near Genoa, Italy in 1968; this plant had the architecture of today's power tower plants with a solar receiver in the center of a field of solar collectors.
The plant was able to produce 1 MW with superheated steam at 100 bar and 500 °C. The 10 MW Solar One power tower was developed in Southern California in 1981. Solar One was converted into Solar Two in 1995, implementing a new design with a molten salt mixture as the receiver working fluid and as a storage medium; the molten salt approach proved effective, Solar Two operated until it was decommissioned in 1999. The parabolic-trough technology of the nearby Solar Energy Generating Systems, begun in 1984, was more workable; the 354 MW SEGS was the largest solar power plant in the world, until 2014. No commercial concentrated solar was constructed from 1990 when SEGS was completed until 2006 when the Compact linear Fresnel reflector system at Liddell Power Station in Australia was built. Few other plants were built with this design although the 5 MW Kimberlina Solar Thermal Energy Plant opened in 2009. In 2007, 75 MW Nevada Solar One was built, a trough design and the first large plant since SEGS.
Between 2009 and 2013, Spain built over standardized in 50 MW blocks. Due to the success of Solar Two, a commercial power plant, called Solar Tres Power Tower, was buil
The Arnolfini Portrait is a 1434 oil painting on oak panel by the Early Netherlandish painter Jan van Eyck. It forms a full-length double portrait, believed to depict the Italian merchant Giovanni di Nicolao Arnolfini and his wife in their home in the Flemish city of Bruges, it is considered one of the most original and complex paintings in Western art, because of its beauty, complex iconography, geometric orthogonal perspective, expansion of the picture space with the use of a mirror. According to Ernst Gombrich "in its own way it was as new and revolutionary as Donatello's or Masaccio's work in Italy. A simple corner of the real world had been fixed on to a panel as if by magic... For the first time in history the artist became the perfect eye-witness in the truest sense of the term"; the portrait has been considered by Erwin Panofsky and some other art historians as a unique form of marriage contract, recorded as a painting. Signed and dated by van Eyck in 1434, it is, with the Ghent Altarpiece by the same artist and his brother Hubert, the oldest famous panel painting to have been executed in oils rather than in tempera.
The painting was bought by the National Gallery in London in 1842. Van Eyck used the technique of applying layer after layer of thin translucent glazes to create a painting with an intensity of both tone and colour; the glowing colours help to highlight the realism, to show the material wealth and opulence of Arnolfini's world. Van Eyck took advantage of the longer drying time of oil paint, compared to tempera, to blend colours by painting wet-in-wet to achieve subtle variations in light and shade to heighten the illusion of three-dimensional forms; the medium of oil paint permitted van Eyck to capture surface appearance and distinguish textures precisely. He rendered the effects of both direct and diffuse light by showing the light from the window on the left reflected by various surfaces, it has been suggested that he used a magnifying glass in order to paint the minute details such as the individual highlights on each of the amber beads hanging beside the mirror. The illusionism of the painting was remarkable for its time, in part for the rendering of detail, but for the use of light to evoke space in an interior, for "its utterly convincing depiction of a room, as well of the people who inhabit it".
Whatever meaning is given to the scene and its details, there has been much debate on this, according to Craig Harbison the painting "is the only fifteenth-century Northern panel to survive in which the artist's contemporaries are shown engaged in some sort of action in a contemporary interior. It is indeed tempting to call this the first genre painting – a painting of everyday life – of modern times"; the painting is in good condition, though with small losses of original paint and damages, which have been retouched. Infrared reflectograms of the painting show many small alterations, or pentimenti, in the underdrawing: to both faces, to the mirror, to other elements; the couple are shown in an upstairs room with a chest and a bed in it during early summer as indicated by the fruit on the cherry tree outside the window. The room functioned as a reception room, as it was the fashion in France and Burgundy where beds in reception rooms were used as seating, for example, when a mother with a new baby received visitors.
The window has six interior wooden shutters, but only the top opening has glass, with clear bulls-eye pieces set in blue and green stained glass. The two figures are richly dressed; the furs may be the expensive sable for him and ermine or miniver for her. He wears a hat of plaited straw dyed black, as worn in the summer at the time, his tabard was more purple than it may be intended to be silk velvet. Underneath he wears a doublet of patterned material silk damask, her dress has elaborate dagging on the sleeves, a long train. Her blue underdress is trimmed with white fur. Although the woman's plain gold necklace and the rings that both wear are the only jewellery visible, both outfits would have been enormously expensive, appreciated as such by a contemporary viewer. There may be an element of restraint in their clothes befitting their merchant status – portraits of aristocrats tend to show gold chains and more decorated cloth, although "the restrained colours of the man's clothing correspond to those favoured by Duke Phillip of Burgundy".
The interior of the room has other signs of wealth. It would have had a mechanism with pulley and chains above, to lower it for managing the candles; the convex mirror at the back, in a wooden frame with scenes of The Passion painted behind glass, is shown larger than such mirrors could be made at this date – another discreet departure from realism by van Eyck. There is no sign of a fireplace, nor anywhere obvious to put one; the oranges casually placed to the left are a sign of wealth. Further signs of luxury are the elaborate bed-hangings and the carvings on the chair and bench against the back wall the small Orien