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99-536: It was designed by Lohan Associates (now Goettsch Partners) and developed by John Buck Company. The UBS Tower was the first large multi-tenant tower to be constructed in Chicago for six years since 1993. The tower's main lobby's glass wall was a first in the United States. The 40-foot (12 m) wall was made out of 5' x 5' glass panes attached to a system of medallions and cable. This cable system

198-405: 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

297-436: 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

396-809: 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

495-647: A bell when struck. In the 20th century, mass-produced glass work including artistic glass vessels was sometimes known as factory glass . Starting in the Middle Ages , glass became more widely produced and used for windows in buildings. Stained glass became common for windows in cathedrals and grand civic buildings. The invention of plate glass and the Bessemer process allowed for glass to be used in larger segments, to support more structural loads, and to be produced at larger scales. A striking example of this

594-485: 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

693-434: A facade engineering and curtain wall design company, designed and installed the first ever cable net glass wall in the United States at the lobby area of One North Wacker in downtown Chicago. The cable net strategy developed effectively minimized the sightlines of the steel support structure supporting the glass, allowing architect Goettsch Partners to achieve maximum transparency with a series of 15 meter glass facades that wrap

792-443: 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

891-408: 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

990-405: 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

1089-561: 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

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1188-482: 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

1287-453: 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

1386-401: 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

1485-622: A range of traditional and contemporary American cuisine as well as other cuisine featured from around the world on a rotating basis. In March 2002, the building was recognized as "Development of the Year” at the 14th Annual Greater Chicago Commercial Real Estate Awards. Glass Glass is an amorphous ( non-crystalline ) solid. Because it 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

1584-462: 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

1683-412: 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

1782-435: 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

1881-413: 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

1980-521: 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

2079-470: A wider use of colored glass, led to cheap glassware in the 1930s, which later became known as Depression glass. As the types of acids used in this process are extremely hazardous, abrasive methods gained popularity. Knitted glass is a technique developed in 2006 by artist Carol Milne , incorporating knitting , lost-wax casting , mold-making , and kiln-casting . It produces works that look knitted, though they are made entirely of glass. In 2015,

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2178-418: 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

2277-552: Is René Roubícek's "Object" 1960 , a blown and hot-worked piece of 52.2 cm (20.6 in) shown at the "Design in an Age of Adversity" exhibition at the Corning Museum of Glass in 2005. A chiselled and bonded plate glass tower by Henry Richardson serves as the memorial to the Connecticut victims of the 9/11 terrorist attacks. In 2021, the artist Guillaume Bottazzi created a three-metre high glass sculpture on

2376-552: 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

2475-714: 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

2574-418: 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

2673-449: 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

2772-676: 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

2871-455: 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

2970-489: 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

3069-434: Is known as studio glass . Some of the earliest and most practical works of glass art were glass vessels. Goblets and pitchers were popular as glassblowing developed as an art form. Many early methods of etching, painting, and forming glass were honed on these vessels. For instance, the millefiori technique dates back at least to Rome . More recently, lead glass or crystal glass were used to make vessels that rang like

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3168-468: Is not so. We have the touch. My son Rudolf has more than I have, because he is my son, and the touch increases in every generation. The only way to become a glass modeler of skill, I have often said to people, is to get a good great-grandfather who loved glass; then he is to have a son with like tastes; he is to be your grandfather. He in turn will have a son who must, as your father, be passionately fond of glass. You, as his son, can then try your hand, and it

3267-422: Is often part of the artwork. Techniques used include stained glass , carving (wheel carving, engraving, or acid etching), frosting, enameling , and gilding (including Angel gilding ). An artist may combine techniques through masking or silkscreening . Glass panels or walls may also be complemented by running water or dynamic lights. The earliest glass art paperweights were produced as utilitarian objects in

3366-901: 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

3465-461: 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

3564-408: 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

3663-436: 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

3762-491: Is worked with a diamond saw, or copper wheels embedded with abrasives and polished to give gleaming facets; the technique used in creating Waterford crystal . Fine paperweights were originally made by skilled workers in the glass factories in Europe and the United States during the classic period (1845-1870.) Since the late 1930s, a small number of very skilled artists have used this art form to express themselves, using mostly

3861-466: Is your own fault if you do not succeed. But, if you do not have such ancestors, it is not your fault. My grandfather was the most widely known glassworker in Bohemia. Over the course of their collected lives Leopold and Rudolf crafted as many as ten thousand glass marine invertebrate models plus the 4,400 botanical ones that are Glass Flowers. The rumor of secret methods is partly owed to the fact that

3960-532: The Glass sea creatures and their younger botanical cousins the Glass Flowers , scientifically accurate models of marine invertebrates and various plant specimens crafted by famed Bohemian lampworkers Leopold and Rudolf Blaschka from 1863 to 1936. The Glass Flowers are a unique collection made for and located only at Harvard Museum of Natural History , while the glass invertebrates are located in collections

4059-524: 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

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4158-581: The Mediated Matter group and Glass Lab at MIT produced a prototype 3D printer that could print with glass, through their G3DP project. This printer allowed creators to vary optical properties and thickness of their pieces. The first works that they printed were a series of artistic vessels, which were included in the Cooper Hewitt 's Beauty exhibit in 2016. Glass printing is theoretically possible at large and small physical scales and has

4257-482: 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

4356-537: 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

4455-554: The Smith Museum of Stained Glass Windows , located in Chicago's Navy Pier , opened as the first museum in America dedicated solely to stained glass windows. The museum features works by Louis Comfort Tiffany and John Lafarge , and is open daily free to the public. The UK's National Glass Centre is located in the city of Sunderland, Tyne and Wear . Among the finest - and arguably the most detailed - examples of glass art are

4554-463: The Venetian Lagoon , (also known as Venetian glass) is the result of hundreds of years of refinement and invention. Murano is still held as the birthplace of modern glass art. Apart from shaping the hot glass, the three main traditional decorative techniques used on formed pieces in recent centuries are enamelled glass , engraved glass and cut glass . The first two are very ancient, but

4653-465: 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

4752-436: 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

4851-419: The lampwork figures of Stanislav Brychta , are generally called art glass. By the 1970s, there were good designs for smaller furnaces, and in the United States, this gave rise to the "studio glass" movement of glassblowers who blew their glass outside of factories, often in their own studios. This coincided with a move towards smaller production runs of particular styles. This movement spread to other parts of

4950-510: 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

5049-461: 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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5148-926: The Chrysler Museum in Norfolk, Virginia , the Museum of Glass in Tacoma, the Metropolitan Museum of Art, the Toledo Museum of Art , and Corning Museum of Glass , in Corning, NY , which houses the world's largest collection of glass art and history, with more than 45,000 objects in its collection. The Museum of Fine Arts in Boston features a 42.5 feet (13.0 m) tall glass sculpture, Lime Green Icicle Tower , by Dale Chihuly. In February 2000

5247-687: 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

5346-543: 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

5445-533: 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

5544-719: 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

5643-483: The body of the wearer. They are partly or entirely made of glass with extreme attention to fit and flexibility. The result is usually delicate, and not intended for regular use. Several of the most common techniques for producing glass art include: blowing , kiln-casting, fusing, slumping, pâté-de-verre, flame-working, hot-sculpting and cold-working. Cold work includes traditional stained glass work as well as other methods of shaping glass at room temperature. Cut glass

5742-565: The capacity for mass production. However, as of 2016 production still requires hand-tuning, and has mainly been used for one-off sculptures. Methods to make patterns on glass include caneworking such as murrine , engraving, enameling , millefiori , flamework , and gilding . Methods used to combine glass elements and work glass into final forms include lampworking . Historical collections of glass art can be found in general museums. Modern works of glass art can be seen in dedicated glass museums and museums of contemporary art. These include

5841-501: The classic period. The first uses of glass were in beads and other small pieces of jewelry and decoration. Beads and jewelry are still among the most common uses of glass in art and can be worked without a furnace . It later became fashionable to wear functional jewelry with glass elements, such as pocket watches and monocles. Starting in the late 20th century, glass couture refers to the creation of exclusive custom-fitted clothing made from sculpted glass. These are made to order for

5940-456: The classic techniques of millefiori and lampwork. Art is sometimes etched into glass via the use of acid, caustic, or abrasive substances. Traditionally this was done after the glass was blown or cast. In the 1920s a new mould-etch process was invented, 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

6039-411: 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

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6138-427: 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

6237-683: 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

6336-466: 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

6435-459: 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

6534-695: 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

6633-555: 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

6732-493: 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

6831-406: 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

6930-505: The highest per square foot of any building in the Chicago Metropolitan Area at an average of over $ 25 per square foot on a triple net basis, grossing up to over $ 40 per square foot. The building amenities also include a two-story underground garage for senior executives, One North Kitchen and Bar, a Conference Center, Fitness Center and Convenience Store. The building also has a cafeteria on the 30th floor, which serves

7029-424: The late 1960s and early 70s, artists such as Francis Whittemore, Paul Stankard , his former assistant Jim D'Onofrio, Chris Buzzini, Delmo and daughter Debbie Tarsitano, Victor Trabucco and sons, Gordon Smith, Rick Ayotte and his daughter Melissa, the father and son team of Bob and Ray Banford, and Ken Rosenfeld began breaking new ground and were able to produce fine paperweights rivaling anything produced in

7128-458: 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

7227-622: 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 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

7326-481: 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

7425-433: 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

7524-619: 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

7623-410: 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

7722-437: The mid 1800s in Europe. Modern artists have elevated the craft to fine art. Glass art paperweights, can incorporate several glass techniques but the most common techniques found are millefiori and lampwork—both techniques that had been around long before the advent of paperweights. In paperweights, the millefiori or sculptural lampwork elements are encapsulated in clear solid crystal creating a completely solid sculptural form. In

7821-550: The mid 20th century there was a resurgence of interest in paperweight making and several artist sought to relearn the craft. In the US, Charles Kaziun started in 1940 to produce buttons, paperweights, inkwells and other bottles, using lampwork of elegant simplicity. In Scotland, the pioneering work of Paul Ysart from the 1930s onward preceded a new generation of artists such as William Manson, Peter McDougall, Peter Holmes and John Deacons. A further impetus to reviving interest in paperweights

7920-409: 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

8019-438: The nineteenth century Glass art Glass art refers to individual works of art that are substantially or wholly made of glass . It ranges in size from monumental works and installation pieces to wall hangings and windows, to works of art made in studios and factories, including glass jewelry and tableware. As a decorative and functional medium, glass was extensively developed in Egypt and Assyria . Glassblowing

8118-666: The perimeter of the lobby space in over 1,500 square meters of glass. Artwork throughout the building is drawn from the UBS PaineWebber Collection of contemporary art pieces and from the UBS Global Asset Management collection of architectural relics. Roy Lichtenstein 's sculpture, Archaic Head, is displayed on the 38th floor near Louis Sullivan's elevator gate, claimed from the old Chicago Stock Exchange. With 1,754,000 sq ft (163,000 m) of floorspace, UBS Tower's rents are among

8217-922: 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

8316-424: 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

8415-603: 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

8514-469: 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

8613-460: 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

8712-569: The third an English invention, around 1730. From the late 19th century a number of other techniques have been added. The turn of the 19th century was the height of the old art glass movement while the factory glass blowers were being replaced by mechanical bottle blowing and continuous window glass. Great ateliers like Tiffany , Lalique , Daum , Gallé , the Corning schools in upper New York state, and Steuben Glass Works took glass art to new levels. The modern use of glass as an artistic medium

8811-451: 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

8910-403: The world as well. Examples of 20th-century studio glass: Combining many of the above techniques, but focusing on art represented in the glass rather than its shape, glass panels or walls can reach tremendous sizes. These may be installed as walls or on top of walls, or hung from a ceiling. Large panels can be found as part of outdoor installation pieces or for interior use. Dedicated lighting

9009-543: The world over. Given the unmatched anatomical flawlessness of both, many believe that the Blaschkas had a secret method of lampworking which they never revealed. This, however, is not true, as Leopold himself noted in an 1889 letter to Mary Lee Ware (the patron sponsor of the Glass Flowers): Many people think that we have some secret apparatus by which we can squeeze glass suddenly into these forms, but it

9108-402: 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

9207-645: The “Domaine des Diamants Blancs”, in the extension of the Mallet-Stevens garden which adjoins the Villa Cavrois . Examples of 21st century glass sculpture: In the early 20th century, most glass production happened in factories. Even individual glassblowers making their own personalized designs would do their work in those large shared buildings. The idea of "art glass", small decorative works made of art, often with designs or objects inside, flourished. Pieces produced in small production runs, such as

9306-474: Was the Crystal Palace in 1851, one of the first buildings to use glass as a primary structural material. In the 20th century, glass became used for tables and shelves, for internal walls, and even for floors. Some of the best known glass sculptures are statuesque or monumental works created by artists Livio Seguso, Karen LaMonte , and Stanislav Libenský and Jaroslava Brychtová . Another example

9405-517: 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

9504-461: Was perhaps invented in the 1st century BC, and featured heavily in Roman glass , which was highly developed with forms such as the cage cup for a luxury market. Islamic glass was the most sophisticated of the early Middle Ages . Then the builders of the great Norman and Gothic cathedrals of Europe took the art of glass to new heights with the use of stained glass windows as a major architectural and decorative element. Glass from Murano , in

9603-556: 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

9702-509: Was tested at pressures above 150 psf, or a wind speed of nearly 250 mph. The glass itself is also noteworthy: an optical interference anti-reflective glass (designed by Schott AG ) with an unusually low surface reflectivity of 1% is used. This imbues the lobby with an almost transparent appearance. Exterior landscaping was designed by the Berkeley, California-based firm, Peter Walker and Partners Landscape Architecture Inc. Enclos,

9801-455: Was the publication of Evangiline Bergstrom's book, Old Glass Paperweights , the first of a new genre. A number of small studios appeared in the middle 20th century, particularly in the US. These may have several to some dozens of workers with various levels of skill cooperating to produce their own distinctive "line". Notable examples are Lundberg Studios, Orient and Flume, Correia Art Glass, St.Clair, Lotton, and Parabelle Glass. Starting in

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