121-478: Not to be confused with Glass . [REDACTED] Look up Glas or glas in Wiktionary, the free dictionary. Glas or GLAS may refer to: Organisations [ edit ] Hans Glas GmbH , a former German automotive company Glas (political party) , Croatian acronym of Građansko-liberalni savez , Civic Liberal Alliance Glas (publisher) ,
242-405: A glass (or vitreous solid) is a non-crystalline solid formed by rapid melt quenching . However, the term "glass" is often defined in a broader sense, to describe any non-crystalline ( amorphous ) solid that exhibits a glass transition when heated towards the liquid state. Glass is an amorphous solid . Although the atomic-scale structure of glass shares characteristics of the structure of
363-436: A supercooled liquid , glass exhibits all the mechanical properties of a solid. As in other amorphous solids , the atomic structure of a glass lacks the long-range periodicity observed in crystalline solids . Due to chemical bonding constraints, glasses do possess a high degree of short-range order with respect to local atomic polyhedra . The notion that glass flows to an appreciable extent over extended periods well below
484-809: A turquoise colour in glass, in contrast to copper(I) oxide (Cu 2 O) which gives a dull red-brown colour. Soda–lime sheet glass is typically used as a transparent glazing material, typically as windows in external walls of buildings. Float or rolled sheet glass products are cut to size either by scoring and snapping the material, laser cutting , water jets , or diamond-bladed saw. The glass may be thermally or chemically tempered (strengthened) for safety and bent or curved during heating. Surface coatings may be added for specific functions such as scratch resistance, blocking specific wavelengths of light (e.g. infrared or ultraviolet ), dirt-repellence (e.g. self-cleaning glass ), or switchable electrochromic coatings. Structural glazing systems represent one of
605-399: A Russian publishing house Arts and media [ edit ] Glas , former name of Glas Srpske , a Bosnian-Herzegovinian newspaper Glas (album) , an album by Nina Chuba Glas (book) , a 1974 book by Jacques Derrida Glas (film) , a 1958 Dutch documentary film Glas (TV channel) , Ukrainian satellite channel People [ edit ] Glas (surname) , including
726-485: A clear "ring" sound when struck. However, lead glass cannot withstand high temperatures well. Lead oxide also facilitates the solubility of other metal oxides and is used in coloured glass. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glass); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in vitreous enamels and glass solders . The high ionic radius of
847-426: A complicated and extensive syllabary. A considerable amount of Babylonian literature was translated from Sumerian originals, and the language of religion and law long continued to be the old agglutinative language of Sumer. Vocabularies, grammars, and interlinear translations were compiled for the use of students, as well as commentaries on the older texts and explanations of obscure words and phrases. The characters of
968-443: A green tint in thick sections. Manganese dioxide (MnO 2 ), which gives glass a purple colour, may be added to remove the green tint given by FeO. FeO and chromium(III) oxide (Cr 2 O 3 ) additives are used in the production of green bottles. Iron (III) oxide , on the other-hand, produces yellow or yellow-brown glass. Low concentrations (0.025 to 0.1%) of cobalt oxide (CoO) produce rich, deep blue cobalt glass . Chromium
1089-408: A human timescale. Silicon dioxide (SiO 2 ) is a common fundamental constituent of glass. Fused quartz is a glass made from chemically pure silica. It has very low thermal expansion and excellent resistance to thermal shock , being able to survive immersion in water while red hot, resists high temperatures (1000–1500 °C) and chemical weathering, and is very hard. It is also transparent to
1210-635: A language of the Zagros possibly related to the Hurro-Urartuan language family , is attested in personal names, rivers and mountains and in various crafts. Akkadian came to be the dominant language during the Akkadian Empire and the Assyrian empires, but Sumerian was retained for administrative, religious, literary and scientific purposes. Different varieties of Akkadian were used until
1331-405: A lighter alternative to traditional glass. Molecular liquids, electrolytes , molten salts , and aqueous solutions are mixtures of different molecules or ions that do not form a covalent network but interact only through weak van der Waals forces or transient hydrogen bonds . In a mixture of three or more ionic species of dissimilar size and shape, crystallization can be so difficult that
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#17327811185851452-438: A list of people with the name Eochaid Faebar Glas , a mythical High King of Ireland See also [ edit ] List of islands called Eilean Glas Doktor Glas , a 1905 novel by Hjalmar Söderberg Glass (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Glas . If an internal link led you here, you may wish to change
1573-561: A long period at a temperature just insufficient to cause fusion. In this way, the crystalline, devitrified material, known as Réaumur's glass porcelain is produced. Although generally transparent to visible light, glasses may be opaque to other wavelengths of light . While silicate glasses are generally opaque to infrared wavelengths with a transmission cut-off at 4 μm, heavy-metal fluoride and chalcogenide glasses are transparent to infrared wavelengths of 7 to 18 μm. The addition of metallic oxides results in different coloured glasses as
1694-482: A mass of hot semi-molten glass, inflating it into a bubble using a hollow blowpipe, and forming it into the required shape by blowing, swinging, rolling, or moulding. While hot, the glass can be worked using hand tools, cut with shears, and additional parts such as handles or feet attached by welding. Flat glass for windows and similar applications is formed by the float glass process, developed between 1953 and 1957 by Sir Alastair Pilkington and Kenneth Bickerstaff of
1815-453: A non-crystalline intergranular phase of grain boundaries . Glass-ceramics exhibit advantageous thermal, chemical, biological, and dielectric properties as compared to metals or organic polymers. The most commercially important property of glass-ceramics is their imperviousness to thermal shock. Thus, glass-ceramics have become extremely useful for countertop cooking and industrial processes. The negative thermal expansion coefficient (CTE) of
1936-488: A patient could not be cured physically, the Babylonian physicians often relied on exorcism to cleanse the patient from any curses . Esagil-kin-apli's Diagnostic Handbook was based on a logical set of axioms and assumptions, including the modern view that through the examination and inspection of the symptoms of a patient, it is possible to determine the patient's disease , its aetiology, its future development, and
2057-401: A plastic resin with glass fibres . It is made by melting glass and stretching the glass into fibres. These fibres are woven together into a cloth and left to set in a plastic resin. Fibreglass has the properties of being lightweight and corrosion resistant and is a good insulator enabling its use as building insulation material and for electronic housing for consumer products. Fibreglass
2178-554: A precursor to the Socratic method . The Ionian philosopher Thales was influenced by Babylonian cosmological ideas. Ancient Mesopotamians had ceremonies each month. The theme of the rituals and festivals for each month was determined by at least six important factors: Some songs were written for the gods but many were written to describe important events. Although music and songs amused kings , they were also enjoyed by ordinary people who liked to sing and dance in their homes or in
2299-761: A recent hypothesis, the Archimedes' screw may have been used by Sennacherib, King of Assyria, for the water systems at the Hanging Gardens of Babylon and Nineveh in the 7th century BC, although mainstream scholarship holds it to be a Greek invention of later times. Later, during the Parthian or Sasanian periods, the Baghdad Battery , which may have been the world's first battery, was created in Mesopotamia. The Ancient Mesopotamian religion
2420-462: A refractive index of 1.4 to 2.4, and an Abbe number (which characterises dispersion) of 15 to 100. The refractive index may be modified by high-density (refractive index increases) or low-density (refractive index decreases) additives. Glass transparency results from the absence of grain boundaries which diffusely scatter light in polycrystalline materials. Semi-opacity due to crystallization may be induced in many glasses by maintaining them for
2541-567: A sacred, ceremonial, literary, and scientific language in Mesopotamia until the 1st century AD. Libraries were extant in towns and temples during the Babylonian Empire. An old Sumerian proverb averred that "he who would excel in the school of the scribes must rise with the dawn." Women as well as men learned to read and write, and for the Semitic Babylonians, this involved knowledge of the extinct Sumerian language, and
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#17327811185852662-412: A spinning metal disk. Several alloys have been produced in layers with thicknesses exceeding 1 millimetre. These are known as bulk metallic glasses (BMG). Liquidmetal Technologies sells several zirconium -based BMGs. Batches of amorphous steel have also been produced that demonstrate mechanical properties far exceeding those found in conventional steel alloys. Experimental evidence indicates that
2783-435: A structural analogue of silica, fluoride , aluminate , phosphate , borate , and chalcogenide glasses) have physicochemical properties useful for their application in fibre-optic waveguides in communication networks and other specialised technological applications. Silica-free glasses may often have poor glass-forming tendencies. Novel techniques, including containerless processing by aerodynamic levitation (cooling
2904-413: A structurally metastable state with respect to its crystalline form, although in certain circumstances, for example in atactic polymers, there is no crystalline analogue of the amorphous phase. Glass is sometimes considered to be a liquid due to its lack of a first-order phase transition where certain thermodynamic variables such as volume , entropy and enthalpy are discontinuous through
3025-415: A table of Pythagorean triples and represents some of the most advanced mathematics prior to Greek mathematics. From Sumerian times, temple priesthoods had attempted to associate current events with certain positions of the planets and stars. This continued to Assyrian times, when Limmu lists were created as a year by year association of events with planetary positions, which, when they have survived to
3146-519: A vast mountainous region. Overland routes in Mesopotamia usually follow the Euphrates because the banks of the Tigris are frequently steep and difficult. The climate of the region is semi-arid with a vast desert expanse in the north which gives way to a 15,000-square-kilometre (5,800 sq mi) region of marshes, lagoons, mudflats, and reed banks in the south. In the extreme south, the Euphrates and
3267-521: A wider spectral range than ordinary glass, extending from the visible further into both the UV and IR ranges, and is sometimes used where transparency to these wavelengths is necessary. Fused quartz is used for high-temperature applications such as furnace tubes, lighting tubes, melting crucibles, etc. However, its high melting temperature (1723 °C) and viscosity make it difficult to work with. Therefore, normally, other substances (fluxes) are added to lower
3388-595: Is an-ki , which refers to the god An and the goddess Ki . Their son was Enlil, the air god. They believed that Enlil was the most powerful god. He was the chief god of the pantheon . The numerous civilizations of the area influenced the Abrahamic religions , especially the Hebrew Bible . Its cultural values and literary influence are especially evident in the Book of Genesis . Giorgio Buccellati believes that
3509-418: Is 3.25 × 10 /°C as compared to about 9 × 10 /°C for a typical soda–lime glass ). They are, therefore, less subject to stress caused by thermal expansion and thus less vulnerable to cracking from thermal shock . They are commonly used for e.g. labware , household cookware , and sealed beam car head lamps . The addition of lead(II) oxide into silicate glass lowers the melting point and viscosity of
3630-552: Is a common volcanic glass with high silica (SiO 2 ) content formed when felsic lava extruded from a volcano cools rapidly. Impactite is a form of glass formed by the impact of a meteorite , where Moldavite (found in central and eastern Europe), and Libyan desert glass (found in areas in the eastern Sahara , the deserts of eastern Libya and western Egypt ) are notable examples. Vitrification of quartz can also occur when lightning strikes sand , forming hollow, branching rootlike structures called fulgurites . Trinitite
3751-414: Is a composite product, although it is probable that some of the stories are artificially attached to the central figure. Mesopotamian mathematics and science was based on a sexagesimal (base 60) numeral system . This is the source of the 60-minute hour, the 24-hour day, and the 360- degree circle. The Sumerian calendar was lunisolar, with three seven-day weeks of a lunar month. This form of mathematics
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3872-714: Is a glassy residue formed from the desert floor sand at the Trinity nuclear bomb test site. Edeowie glass , found in South Australia , is proposed to originate from Pleistocene grassland fires, lightning strikes, or hypervelocity impact by one or several asteroids or comets . Naturally occurring obsidian glass was used by Stone Age societies as it fractures along very sharp edges, making it ideal for cutting tools and weapons. Glassmaking dates back at least 6000 years, long before humans had discovered how to smelt iron. Archaeological evidence suggests that
3993-418: Is a very powerful colouring agent, yielding dark green. Sulphur combined with carbon and iron salts produces amber glass ranging from yellowish to almost black. A glass melt can also acquire an amber colour from a reducing combustion atmosphere. Cadmium sulfide produces imperial red , and combined with selenium can produce shades of yellow, orange, and red. Addition of copper(II) oxide (CuO) produces
4114-469: Is accurate to about six decimal digits, and is the closest possible three-place sexagesimal representation of √ 2 : The Babylonians were not interested in exact solutions, but rather approximations, and so they would commonly use linear interpolation to approximate intermediate values. One of the most famous tablets is the Plimpton 322 tablet , created around 1900–1600 BC, which gives
4235-449: Is achieved by homogenizing the raw materials mixture ( glass batch ), stirring the melt, and crushing and re-melting the first melt. The obtained glass is usually annealed to prevent breakage during processing. Colour in glass may be obtained by addition of homogenously distributed electrically charged ions (or colour centres ). While ordinary soda–lime glass appears colourless in thin section, iron(II) oxide (FeO) impurities produce
4356-597: Is compatible with ergodic axioms. Logic was employed to some extent in Babylonian astronomy and medicine. Babylonian thought had a considerable influence on early Ancient Greek and Hellenistic philosophy . In particular, the Babylonian text Dialogue of Pessimism contains similarities to the agonistic thought of the Sophists , the Heraclitean doctrine of dialectic , and the dialogs of Plato , as well as
4477-676: Is extensively used for fibreglass , used for making glass-reinforced plastics (boats, fishing rods, etc.), top-of-stove cookware, and halogen bulb glass. The addition of barium also increases the refractive index. Thorium oxide gives glass a high refractive index and low dispersion and was formerly used in producing high-quality lenses, but due to its radioactivity has been replaced by lanthanum oxide in modern eyeglasses. Iron can be incorporated into glass to absorb infrared radiation, for example in heat-absorbing filters for movie projectors, while cerium(IV) oxide can be used for glass that absorbs ultraviolet wavelengths. Fluorine lowers
4598-455: Is in widespread use in optical systems due to its ability to refract, reflect, and transmit light following geometrical optics . The most common and oldest applications of glass in optics are as lenses , windows , mirrors , and prisms . The key optical properties refractive index , dispersion , and transmission , of glass are strongly dependent on chemical composition and, to a lesser degree, its thermal history. Optical glass typically has
4719-489: Is incorrect, as once solidified, glass stops flowing. The sags and ripples observed in old glass were already there the day it was made; manufacturing processes used in the past produced sheets with imperfect surfaces and non-uniform thickness (the near-perfect float glass used today only became widespread in the 1960s). A 2017 study computed the rate of flow of the medieval glass used in Westminster Abbey from
4840-487: Is often transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window panes, tableware , and optics . Some common objects made of glass are named after the material, e.g. "glass" , " glasses ", " magnifying glass ". Glass is most often formed by rapid cooling ( quenching ) of the molten form. Some glasses such as volcanic glass are naturally occurring, and obsidian has been used to make arrowheads and knives since
4961-901: Is produced by forcing molten glass through a fine mesh by centripetal force and breaking the extruded glass fibres into short lengths using a stream of high-velocity air. The fibres are bonded with an adhesive spray and the resulting wool mat is cut and packed in rolls or panels. Besides common silica-based glasses many other inorganic and organic materials may also form glasses, including metals , aluminates , phosphates , borates , chalcogenides , fluorides , germanates (glasses based on GeO 2 ), tellurites (glasses based on TeO 2 ), antimonates (glasses based on Sb 2 O 3 ), arsenates (glasses based on As 2 O 3 ), titanates (glasses based on TiO 2 ), tantalates (glasses based on Ta 2 O 5 ), nitrates , carbonates , plastics , acrylic , and many other substances. Some of these glasses (e.g. Germanium dioxide (GeO 2 , Germania), in many respects
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5082-461: Is stronger than most metals, with a theoretical tensile strength for pure, flawless glass estimated at 14 to 35 gigapascals (2,000,000 to 5,100,000 psi) due to its ability to undergo reversible compression without fracture. However, the presence of scratches, bubbles, and other microscopic flaws lead to a typical range of 14 to 175 megapascals (2,000 to 25,400 psi) in most commercial glasses. Several processes such as toughening can increase
5203-408: Is sufficiently rapid (relative to the characteristic crystallization time) then crystallization is prevented and instead, the disordered atomic configuration of the supercooled liquid is frozen into the solid state at T g . The tendency for a material to form a glass while quenched is called glass-forming ability. This ability can be predicted by the rigidity theory . Generally, a glass exists in
5324-476: Is the site of the earliest developments of the Neolithic Revolution from around 10,000 BC. It has been identified as having "inspired some of the most important developments in human history, including the invention of the wheel , the planting of the first cereal crops , the development of cursive script, mathematics , astronomy , and agriculture ". It is recognised as the cradle of some of
5445-436: Is transparent, easily formed, and most suitable for window glass and tableware. However, it has a high thermal expansion and poor resistance to heat. Soda–lime glass is typically used for windows , bottles , light bulbs , and jars . Borosilicate glasses (e.g. Pyrex , Duran ) typically contain 5–13% boron trioxide (B 2 O 3 ). Borosilicate glasses have fairly low coefficients of thermal expansion (7740 Pyrex CTE
5566-421: Is uncertain. The Babylonian development of methods for predicting the motions of the planets is considered to be a major episode in the history of astronomy . The only Greek-Babylonian astronomer known to have supported a heliocentric model of planetary motion was Seleucus of Seleucia (b. 190 BC). Seleucus is known from the writings of Plutarch . He supported Aristarchus of Samos' heliocentric theory where
5687-561: The Akkadian Empire . The early second millennium BC saw the polarization of Mesopotamian society into Assyria in the north and Babylonia in the south. From 900 to 612 BC, the Neo-Assyrian Empire asserted control over much of the ancient Near East. Subsequently, the Babylonians, who had long been overshadowed by Assyria, seized power , dominating the region for a century as the final independent Mesopotamian realm until
5808-674: The Earth rotated around its own axis which in turn revolved around the Sun . According to Plutarch , Seleucus even proved the heliocentric system, but it is not known what arguments he used, except that he correctly theorized on tides as a result of the Moon's attraction. Babylonian astronomy served as the basis for much of Greek , classical Indian , Sassanian, Byzantine , Syrian , medieval Islamic , Central Asian , and Western European astronomy. The oldest Babylonian texts on medicine date back to
5929-613: The Jazira , is the area between the Euphrates and the Tigris from their sources down to Baghdad . Lower Mesopotamia is the area from Baghdad to the Persian Gulf and includes Kuwait and parts of western Iran. In modern academic usage, the term Mesopotamia often also has a chronological connotation. It is usually used to designate the area until the Muslim conquests , with names like Syria , Jazira , and Iraq being used to describe
6050-524: The Late Bronze Age , there was a rapid growth in glassmaking technology in Egypt and Western Asia . Archaeological finds from this period include coloured glass ingots , vessels, and beads. Much early glass production relied on grinding techniques borrowed from stoneworking , such as grinding and carving glass in a cold state. The term glass has its origins in the late Roman Empire , in
6171-650: The Old Babylonian period in the first half of the 2nd millennium BC . The most extensive Babylonian medical text, however, is the Diagnostic Handbook written by the ummânū , or chief scholar, Esagil-kin-apli of Borsippa , during the reign of the Babylonian king Adad-apla-iddina (1069–1046 BC). Along with contemporary Egyptian medicine , the Babylonians introduced the concepts of diagnosis , prognosis , physical examination , enemas , and prescriptions . The Diagnostic Handbook introduced
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#17327811185856292-535: The Renaissance period in Europe, the use of large stained glass windows became much less prevalent, although stained glass had a major revival with Gothic Revival architecture in the 19th century. During the 13th century, the island of Murano , Venice , became a centre for glass making, building on medieval techniques to produce colourful ornamental pieces in large quantities. Murano glass makers developed
6413-537: The Roman glass making centre at Trier (located in current-day Germany) where the late-Latin term glesum originated, likely from a Germanic word for a transparent , lustrous substance. Glass objects have been recovered across the Roman Empire in domestic, funerary , and industrial contexts, as well as trade items in marketplaces in distant provinces. Examples of Roman glass have been found outside of
6534-1270: The Stone Age . Archaeological evidence suggests glassmaking dates back to at least 3600 BC in Mesopotamia , Egypt , or Syria . The earliest known glass objects were beads , perhaps created accidentally during metalworking or the production of faience , which is a form of pottery using lead glazes. Due to its ease of formability into any shape, glass has been traditionally used for vessels, such as bowls , vases , bottles , jars and drinking glasses. Soda–lime glass , containing around 70% silica , accounts for around 90% of modern manufactured glass. Glass can be coloured by adding metal salts or painted and printed with vitreous enamels , leading to its use in stained glass windows and other glass art objects. The refractive , reflective and transmission properties of glass make glass suitable for manufacturing optical lenses , prisms , and optoelectronics materials. Extruded glass fibres have applications as optical fibres in communications networks, thermal insulating material when matted as glass wool to trap air, or in glass-fibre reinforced plastic ( fibreglass ). The standard definition of
6655-465: The dielectric constant of glass. Fluorine is highly electronegative and lowers the polarizability of the material. Fluoride silicate glasses are used in the manufacture of integrated circuits as an insulator. Glass-ceramic materials contain both non-crystalline glass and crystalline ceramic phases. They are formed by controlled nucleation and partial crystallisation of a base glass by heat treatment. Crystalline grains are often embedded within
6776-436: The glass batch preparation and mixing, the raw materials are transported to the furnace. Soda–lime glass for mass production is melted in glass-melting furnaces . Smaller-scale furnaces for speciality glasses include electric melters, pot furnaces, and day tanks. After melting, homogenization and refining (removal of bubbles), the glass is formed . This may be achieved manually by glassblowing , which involves gathering
6897-438: The marketplaces . Songs were sung to children who passed them on to their children. Thus songs were passed on through many generations as an oral tradition until writing was more universal. These songs provided a means of passing on through the centuries highly important information about historical events. Hunting was popular among Assyrian kings. Boxing and wrestling feature frequently in art, and some form of polo
7018-407: The É , a temple dedicated to the goddess Inanna at Uruk, from a building labeled as Temple C by its excavators. The early logographic system of cuneiform script took many years to master. Thus, only a limited number of individuals were hired as scribes to be trained in its use. It was not until the widespread use of a syllabic script was adopted under Sargon's rule that significant portions of
7139-701: The (two) rivers") comes from the ancient Greek root words μέσος ( mesos , 'middle') and ποταμός ( potamos , 'river') and translates to '(land) between rivers', likely being a calque of the older Aramaic term, with the Aramaic term itself likely being a calque of the Akkadian birit narim . It is used throughout the Greek Septuagint ( c. 250 BC ) to translate the Hebrew and Aramaic equivalent Naharaim . An even earlier Greek usage of
7260-510: The 10th century onwards, glass was employed in stained glass windows of churches and cathedrals , with famous examples at Chartres Cathedral and the Basilica of Saint-Denis . By the 14th century, architects were designing buildings with walls of stained glass such as Sainte-Chapelle , Paris, (1203–1248) and the East end of Gloucester Cathedral . With the change in architectural style during
7381-461: The 1930s, which later became known as Depression glass . In the 1950s, Pilkington Bros. , England , developed the float glass process, producing high-quality distortion-free flat sheets of glass by floating on molten tin . Modern multi-story buildings are frequently constructed with curtain walls made almost entirely of glass. Laminated glass has been widely applied to vehicles for windscreens. Optical glass for spectacles has been used since
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#17327811185857502-432: The 1st century BC and 3rd century AD, including Adiabene , Osroene , and Hatra . The regional toponym Mesopotamia ( / ˌ m ɛ s ə p ə ˈ t eɪ m i ə / , Ancient Greek : Μεσοποταμία '[land] between rivers'; Arabic : بِلَاد ٱلرَّافِدَيْن Bilād ar-Rāfidayn or بَيْن ٱلنَّهْرَيْن Bayn an-Nahrayn ; Persian : میانرودان miyân rudân ; Syriac : ܒܝܬ ܢܗܪ̈ܝܢ Beth Nahrain "(land) between
7623-540: The 8,000-year-old remains of early farmers found at an ancient graveyard in Germany . They compared the genetic signatures to those of modern populations and found similarities with the DNA of people living in today's Turkey and Iraq . The earliest language written in Mesopotamia was Sumerian , an agglutinative language isolate . Along with Sumerian, Semitic languages were also spoken in early Mesopotamia. Subartuan ,
7744-473: The Mesopotamian population became literate. Massive archives of texts were recovered from the archaeological contexts of Old Babylonian scribal schools, through which literacy was disseminated. Akkadian gradually replaced Sumerian as the spoken language of Mesopotamia somewhere around the turn of the 3rd and the 2nd millennium BC. The exact dating being a matter of debate. Sumerian continued to be used as
7865-687: The Middle Ages. The production of lenses has become increasingly proficient, aiding astronomers as well as having other applications in medicine and science. Glass is also employed as the aperture cover in many solar energy collectors. In the 21st century, glass manufacturers have developed different brands of chemically strengthened glass for widespread application in touchscreens for smartphones , tablet computers , and many other types of information appliances . These include Gorilla Glass , developed and manufactured by Corning , AGC Inc. 's Dragontrail and Schott AG 's Xensation. Glass
7986-543: The Pb ion renders it highly immobile and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda–lime glass (10 vs 10 Ω⋅cm, DC at 250 °C). Aluminosilicate glass typically contains 5–10% alumina (Al 2 O 3 ). Aluminosilicate glass tends to be more difficult to melt and shape compared to borosilicate compositions but has excellent thermal resistance and durability. Aluminosilicate glass
8107-472: The Tigris unite and empty into the Persian Gulf . The arid environment ranges from the northern areas of rain-fed agriculture to the south where irrigation of agriculture is essential. This irrigation is aided by a high water table and by melting snows from the high peaks of the northern Zagros Mountains and from the Armenian Highlands, the source of the Tigris and Euphrates Rivers that give
8228-533: The UK's Pilkington Brothers, who created a continuous ribbon of glass using a molten tin bath on which the molten glass flows unhindered under the influence of gravity. The top surface of the glass is subjected to nitrogen under pressure to obtain a polished finish. Container glass for common bottles and jars is formed by blowing and pressing methods. This glass is often slightly modified chemically (with more alumina and calcium oxide) for greater water resistance. Once
8349-719: The action of water, making it an ideal material for the manufacture of containers for foodstuffs and most chemicals. Nevertheless, although usually highly resistant to chemical attack, glass will corrode or dissolve under some conditions. The materials that make up a particular glass composition affect how quickly the glass corrodes. Glasses containing a high proportion of alkali or alkaline earth elements are more susceptible to corrosion than other glass compositions. The density of glass varies with chemical composition with values ranging from 2.2 grams per cubic centimetre (2,200 kg/m ) for fused silica to 7.2 grams per cubic centimetre (7,200 kg/m ) for dense flint glass. Glass
8470-623: The ancient history of lower Mesopotamia—commenced in the early-third millennium BC with cuneiform records of early dynastic kings. This entire history ends with either the arrival of the Achaemenid Empire in the late 6th century BC or with the Muslim conquest and the establishment of the Caliphate in the late 7th century AD, from which point the region came to be known as Iraq . In the long span of this period, Mesopotamia housed some of
8591-410: The chances of the patient's recovery. Esagil-kin-apli discovered a variety of illnesses and diseases and described their symptoms in his Diagnostic Handbook . These include the symptoms for many varieties of epilepsy and related ailments along with their diagnosis and prognosis. Some treatments used were likely based off the known characteristics of the ingredients used. The others were based on
8712-729: The city of Eridu , the Akkadian kingdoms, the Third Dynasty of Ur , and the various Assyrian empires. Some of the important historical Mesopotamian leaders were Ur-Nammu (king of Ur), Sargon of Akkad (who established the Akkadian Empire), Hammurabi (who established the Old Babylonian state), Ashur-uballit I and Tiglath-Pileser I (who established the Assyrian Empire). Scientists analysed DNA from
8833-411: The cost factor has a low priority. In the laboratory mostly pure chemicals are used. Care must be taken that the raw materials have not reacted with moisture or other chemicals in the environment (such as alkali or alkaline earth metal oxides and hydroxides, or boron oxide ), or that the impurities are quantified (loss on ignition). Evaporation losses during glass melting should be considered during
8954-427: The crystalline ceramic phase can be balanced with the positive CTE of the glassy phase. At a certain point (~70% crystalline) the glass-ceramic has a net CTE near zero. This type of glass-ceramic exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °C. Fibreglass (also called glass fibre reinforced plastic, GRP) is a composite material made by reinforcing
9075-614: The cultural mix. Periodic breakdowns in the cultural system have occurred for a number of reasons. The demands for labor has from time to time led to population increases that push the limits of the ecological carrying capacity , and should a period of climatic instability ensue, collapsing central government and declining populations can occur. Alternatively, military vulnerability to invasion from marginal hill tribes or nomadic pastoralists has led to periods of trade collapse and neglect of irrigation systems. Equally, centripetal tendencies amongst city-states have meant that central authority over
9196-421: The cycles of the moon. They divided the year into two seasons: summer and winter. The origins of astronomy as well as astrology date from this time. During the 8th and 7th centuries BC, Babylonian astronomers developed a new approach to astronomy. They began studying philosophy dealing with the ideal nature of the early universe and began employing an internal logic within their predictive planetary systems. This
9317-683: The desired form is obtained, glass is usually annealed for the removal of stresses and to increase the glass's hardness and durability. Surface treatments, coatings or lamination may follow to improve the chemical durability ( glass container coatings , glass container internal treatment ), strength ( toughened glass , bulletproof glass , windshields ), or optical properties ( insulated glazing , anti-reflective coating ). New chemical glass compositions or new treatment techniques can be initially investigated in small-scale laboratory experiments. The raw materials for laboratory-scale glass melts are often different from those used in mass production because
9438-783: The eastern regions of Mesopotamia fell to the Sassanid Persians . The division of the region between the Roman Byzantine Empire from 395 AD and the Sassanid Empire lasted until the 7th century Muslim conquest of Persia of the Sasanian Empire and the Muslim conquest of the Levant from the Byzantines. A number of primarily neo-Assyrian and Christian native Mesopotamian states existed between
9559-478: The end of the Neo-Babylonian period. Old Aramaic , which had already become common in Mesopotamia, then became the official provincial administration language of first the Neo-Assyrian Empire , and then the Achaemenid Empire : the official lect is called Imperial Aramaic . Akkadian fell into disuse, but both it and Sumerian were still used in temples for some centuries. The last Akkadian texts date from
9680-466: The exceptionally clear colourless glass cristallo , so called for its resemblance to natural crystal, which was extensively used for windows, mirrors, ships' lanterns, and lenses. In the 13th, 14th, and 15th centuries, enamelling and gilding on glass vessels were perfected in Egypt and Syria. Towards the end of the 17th century, Bohemia became an important region for glass production, remaining so until
9801-459: The first true synthetic glass was made in Lebanon and the coastal north Syria , Mesopotamia or ancient Egypt . The earliest known glass objects, of the mid-third millennium BC, were beads , perhaps initially created as accidental by-products of metalworking ( slags ) or during the production of faience , a pre-glass vitreous material made by a process similar to glazing . Early glass
9922-754: The former Roman Empire in China , the Baltics , the Middle East , and India . The Romans perfected cameo glass , produced by etching and carving through fused layers of different colours to produce a design in relief on the glass object. In post-classical West Africa, Benin was a manufacturer of glass and glass beads. Glass was used extensively in Europe during the Middle Ages . Anglo-Saxon glass has been found across England during archaeological excavations of both settlement and cemetery sites. From
10043-555: The glass and melt phases. Important polymer glasses include amorphous and glassy pharmaceutical compounds. These are useful because the solubility of the compound is greatly increased when it is amorphous compared to the same crystalline composition. Many emerging pharmaceuticals are practically insoluble in their crystalline forms. Many polymer thermoplastics familiar to everyday use are glasses. For many applications, like glass bottles or eyewear , polymer glasses ( acrylic glass , polycarbonate or polyethylene terephthalate ) are
10164-493: The glass transition range. The glass transition may be described as analogous to a second-order phase transition where the intensive thermodynamic variables such as the thermal expansivity and heat capacity are discontinuous. However, the equilibrium theory of phase transformations does not hold for glass, and hence the glass transition cannot be classed as one of the classical equilibrium phase transformations in solids. Glass can form naturally from volcanic magma. Obsidian
10285-406: The glass transition temperature is not supported by empirical research or theoretical analysis (see viscosity in solids ). Though atomic motion at glass surfaces can be observed, and viscosity on the order of 10 –10 Pa s can be measured in glass, such a high value reinforces the fact that glass would not change shape appreciably over even large periods of time. For melt quenching, if the cooling
10406-465: The late 1st century AD. Early in Mesopotamia's history, around the mid-4th millennium BC, cuneiform was invented for the Sumerian language. Cuneiform literally means "wedge-shaped", due to the triangular tip of the stylus used for impressing signs on wet clay. The standardized form of each cuneiform sign appears to have been developed from pictograms . The earliest texts, 7 archaic tablets, come from
10527-415: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Glas&oldid=1241543461 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Glass Glass is an amorphous ( non-crystalline ) solid. Because it
10648-458: The liquid can easily be supercooled into a glass. Examples include LiCl: R H 2 O (a solution of lithium chloride salt and water molecules) in the composition range 4< R <8. sugar glass , or Ca 0.4 K 0.6 (NO 3 ) 1.4 . Glass electrolytes in the form of Ba-doped Li-glass and Ba-doped Na-glass have been proposed as solutions to problems identified with organic liquid electrolytes used in modern lithium-ion battery cells. Following
10769-481: The melt whilst it floats on a gas stream) or splat quenching (pressing the melt between two metal anvils or rollers), may be used to increase the cooling rate or to reduce crystal nucleation triggers. In the past, small batches of amorphous metals with high surface area configurations (ribbons, wires, films, etc.) have been produced through the implementation of extremely rapid rates of cooling. Amorphous metal wires have been produced by sputtering molten metal onto
10890-433: The melt. The high density of lead glass (silica + lead oxide (PbO) + potassium oxide (K 2 O) + soda (Na 2 O) + zinc oxide (ZnO) + alumina) results in a high electron density, and hence high refractive index, making the look of glassware more brilliant and causing noticeably more specular reflection and increased optical dispersion . Lead glass has a high elasticity, making the glassware more workable and giving rise to
11011-619: The melting temperature and simplify glass processing. Sodium carbonate (Na 2 CO 3 , "soda") is a common additive and acts to lower the glass-transition temperature. However, sodium silicate is water-soluble , so lime (CaO, calcium oxide , generally obtained from limestone ), along with magnesium oxide (MgO), and aluminium oxide (Al 2 O 3 ), are commonly added to improve chemical durability. Soda–lime glasses (Na 2 O) + lime (CaO) + magnesia (MgO) + alumina (Al 2 O 3 ) account for over 75% of manufactured glass, containing about 70 to 74% silica by weight. Soda–lime–silicate glass
11132-410: The metallic ions will absorb wavelengths of light corresponding to specific colours. In the manufacturing process, glasses can be poured, formed, extruded and moulded into forms ranging from flat sheets to highly intricate shapes. The finished product is brittle but can be laminated or tempered to enhance durability. Glass is typically inert, resistant to chemical attack, and can mostly withstand
11253-472: The methods of therapy and aetiology and the use of empiricism , logic , and rationality in diagnosis, prognosis and therapy. The text contains a list of medical symptoms and often detailed empirical observations along with logical rules used in combining observed symptoms on the body of a patient with its diagnosis and prognosis. The symptoms and diseases of a patient were treated through therapeutic means such as bandages , creams and pills . If
11374-670: The modern era. In 539 BC, Mesopotamia was conquered by the Achaemenid Empire . The area was next conquered by Alexander the Great in 332 BC. After his death, it became part of the Greek Seleucid Empire . Around 150 BC, Mesopotamia was under the control of the Parthian Empire . It became a battleground between the Romans and Parthians, with western parts of the region coming under ephemeral Roman control. In 226 AD,
11495-409: The most significant architectural innovations of modern times, where glass buildings now often dominate the skylines of many modern cities . These systems use stainless steel fittings countersunk into recesses in the corners of the glass panels allowing strengthened panes to appear unsupported creating a flush exterior. Structural glazing systems have their roots in iron and glass conservatories of
11616-530: The name Mesopotamia is evident from The Anabasis of Alexander , which was written in the late 2nd century AD but specifically refers to sources from the time of Alexander the Great . In the Anabasis , Mesopotamia was used to designate the land east of the Euphrates in north Syria . The Akkadian term biritum/birit narim corresponded to a similar geographical concept. Later, the term Mesopotamia
11737-530: The nineteenth century Mesopotamia Mesopotamia is a historical region of West Asia situated within the Tigris–Euphrates river system , in the northern part of the Fertile Crescent . Today, Mesopotamia is known as present-day Iraq . In the broader sense, the historical region of Mesopotamia also includes parts of present-day Iran , Turkey , Syria and Kuwait . Mesopotamia
11858-420: The origins of philosophy can be traced back to early Mesopotamian wisdom , which embodied certain philosophies of life, particularly ethics , in the forms of dialectic , dialogues , epic poetry , folklore , hymns , lyrics , prose works, and proverbs . Babylonian reason and rationality developed beyond empirical observation. Babylonian thought was also based on an open-systems ontology which
11979-402: The present day, allow accurate associations of relative with absolute dating for establishing the history of Mesopotamia. The Babylonian astronomers were very adept at mathematics and could predict eclipses and solstices . Scholars thought that everything had some purpose in astronomy. Most of these related to religion and omens. Mesopotamian astronomers worked out a 12-month calendar based on
12100-425: The region after that date. It has been argued that these later euphemisms are Eurocentric terms attributed to the region in the midst of various 19th-century Western encroachments. Mesopotamia encompasses the land between the Euphrates and Tigris rivers, both of which have their headwaters in the neighboring Armenian highlands . Both rivers are fed by numerous tributaries, and the entire river system drains
12221-441: The region its name. The usefulness of irrigation depends upon the ability to mobilize sufficient labor for the construction and maintenance of canals, and this, from the earliest period, has assisted the development of urban settlements and centralized systems of political authority. Agriculture throughout the region has been supplemented by nomadic pastoralism, where tent-dwelling nomads herded sheep and goats (and later camels) from
12342-461: The river pastures in the dry summer months, out into seasonal grazing lands on the desert fringe in the wet winter season. The area is generally lacking in building stone, precious metals, and timber, and so historically has relied upon long-distance trade of agricultural products to secure these items from outlying areas. In the marshlands to the south of the area, a complex water-borne fishing culture has existed since prehistoric times and has added to
12463-424: The selection of the raw materials, e.g., sodium selenite may be preferred over easily evaporating selenium dioxide (SeO 2 ). Also, more readily reacting raw materials may be preferred over relatively inert ones, such as aluminium hydroxide (Al(OH) 3 ) over alumina (Al 2 O 3 ). Usually, the melts are carried out in platinum crucibles to reduce contamination from the crucible material. Glass homogeneity
12584-603: The start of the 20th century. By the 17th century, glass in the Venetian tradition was also being produced in England . In about 1675, George Ravenscroft invented lead crystal glass, with cut glass becoming fashionable in the 18th century. Ornamental glass objects became an important art medium during the Art Nouveau period in the late 19th century. Throughout the 20th century, new mass production techniques led to
12705-469: The strength of glass. Carefully drawn flawless glass fibres can be produced with a strength of up to 11.5 gigapascals (1,670,000 psi). The observation that old windows are sometimes found to be thicker at the bottom than at the top is often offered as supporting evidence for the view that glass flows over a timescale of centuries, the assumption being that the glass has exhibited the liquid property of flowing from one shape to another. This assumption
12826-538: The syllabary were all arranged and named, and elaborate lists were drawn up. Many Babylonian literary works are still studied today. One of the most famous of these was the Epic of Gilgamesh , in twelve books, translated from the original Sumerian by a certain Sîn-lēqi-unninni , and arranged upon an astronomical principle. Each division contains the story of a single adventure in the career of Gilgamesh . The whole story
12947-550: The symbolic qualities. Mesopotamian people invented many technologies including metal and copper-working, glass and lamp making, textile weaving, flood control , water storage, and irrigation. They were also one of the first Bronze Age societies in the world. They developed from copper, bronze, and gold on to iron. Palaces were decorated with hundreds of kilograms of these very expensive metals. Also, copper, bronze, and iron were used for armor as well as for different weapons such as swords, daggers, spears, and maces . According to
13068-460: The system Al-Fe-Si may undergo a first-order transition to an amorphous form (dubbed "q-glass") on rapid cooling from the melt. Transmission electron microscopy (TEM) images indicate that q-glass nucleates from the melt as discrete particles with uniform spherical growth in all directions. While x-ray diffraction reveals the isotropic nature of q-glass, a nucleation barrier exists implying an interfacial discontinuity (or internal surface) between
13189-418: The volume of the frustum of a cone or a square pyramid was incorrectly taken as the product of the height and half the sum of the bases. Also, there was a recent discovery in which a tablet used π as 25/8 (3.125 instead of 3.14159~). The Babylonians are also known for the Babylonian mile, which was a measure of distance equal to about seven modern miles (11 km). This measurement for distances eventually
13310-704: The whole region, when imposed, has tended to be ephemeral, and localism has fragmented power into tribal or smaller regional units. These trends have continued to the present day in Iraq. The prehistory of the Ancient Near East begins in the Lower Paleolithic period. Therein, writing emerged with a pictographic script, Proto-cuneiform , in the Uruk IV period ( c. late 4th millennium BC ). The documented record of actual historical events—and
13431-451: The widespread availability of glass in much larger amounts, making it practical as a building material and enabling new applications of glass. In the 1920s a mould -etch process was developed, in which art was etched directly into the mould so that each cast piece emerged from the mould with the image already on the surface of the glass. This reduced manufacturing costs and, combined with a wider use of coloured glass, led to cheap glassware in
13552-427: The world's earliest civilizations. The Sumerians and Akkadians , each originating from different areas, dominated Mesopotamia from the beginning of recorded history ( c. 3100 BC ) to the fall of Babylon in 539 BC. The rise of empires, beginning with Sargon of Akkad around 2350 BC, characterized the subsequent 2,000 years of Mesopotamian history, marked by the succession of kingdoms and empires such as
13673-812: The world's most ancient highly developed, and socially complex states. The region was one of the four riverine civilizations where writing was invented, along with the Nile valley in Ancient Egypt , the Indus Valley civilization in the Indian subcontinent , and the Yellow River in Ancient China . Mesopotamia housed historically important cities such as Uruk , Nippur , Nineveh , Assur and Babylon , as well as major territorial states such as
13794-402: The year 1268. The study found that the room temperature viscosity of this glass was roughly 10 Pa · s which is about 10 times less viscous than a previous estimate made in 1998, which focused on soda-lime silicate glass. Even with this lower viscosity, the study authors calculated that the maximum flow rate of medieval glass is 1 nm per billion years, making it impossible to observe in
13915-482: Was an important contribution to astronomy and the philosophy of science and some scholars have thus referred to this new approach as the first scientific revolution. This new approach to astronomy was adopted and further developed in Greek and Hellenistic astronomy. In Seleucid and Parthian times, the astronomical reports were thoroughly scientific. How much earlier their advanced knowledge and methods were developed
14036-500: Was converted to a time-mile used for measuring the travel of the Sun, therefore, representing time. The roots of algebra can be traced to the ancient Babylonia who developed an advanced arithmetical system with which they were able to do calculations in an algorithmic fashion. The Babylonian clay tablet YBC 7289 ( c. 1800 –1600 BC) gives an approximation of √ 2 in four sexagesimal figures, 1 24 51 10 , which
14157-412: Was instrumental in early map-making . The Babylonians also had theorems on how to measure the area of several shapes and solids. They measured the circumference of a circle as three times the diameter and the area as one-twelfth the square of the circumference, which would be correct if π were fixed at 3. The volume of a cylinder was taken as the product of the area of the base and the height; however,
14278-630: Was more generally applied to all the lands between the Euphrates and the Tigris , thereby incorporating not only parts of Syria but also almost all of Iraq and southeastern Turkey . The neighbouring steppes to the west of the Euphrates and the western part of the Zagros Mountains are also often included under the wider term Mesopotamia . A further distinction is usually made between Northern or Upper Mesopotamia and Southern or Lower Mesopotamia . Upper Mesopotamia, also known as
14399-517: Was originally used in the United Kingdom and United States during World War II to manufacture radomes . Uses of fibreglass include building and construction materials, boat hulls, car body parts, and aerospace composite materials. Glass-fibre wool is an excellent thermal and sound insulation material, commonly used in buildings (e.g. attic and cavity wall insulation ), and plumbing (e.g. pipe insulation ), and soundproofing . It
14520-496: Was rarely transparent and often contained impurities and imperfections, and is technically faience rather than true glass, which did not appear until the 15th century BC. However, red-orange glass beads excavated from the Indus Valley Civilization dated before 1700 BC (possibly as early as 1900 BC) predate sustained glass production, which appeared around 1600 BC in Mesopotamia and 1500 BC in Egypt. During
14641-450: Was the first recorded. Mesopotamians believed that the world was a flat disc, surrounded by a huge, holed space, and above that, heaven . They believed that water was everywhere, the top, bottom and sides, and that the universe was born from this enormous sea. Mesopotamian religion was polytheistic . Although the beliefs described above were held in common among Mesopotamians, there were regional variations. The Sumerian word for universe
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