glass
The term glass scientifically on any solid material has a crystalline structure does not show a glass transition when heated towards the liquid composition.
More types of glass commonly used through the ages, and especially in our time is used in windows and crockery drinking industry is a glass of lime soda, which consists of 75% of the silica oxide Alsodiomuoksid calcium and a number of additives Alokhry.zjaj is a substance amorphous solid at temperatures cooled and liquid temperature at high temperature brittle transparent.
historical overview
The beginning of the discovery of glass
There was a group of sailors on the beach of sand containing silica material and Shahu set fire accidentally found the glossy transparent liquid, and this was the beginning of the discovery of glass.
The porcelain decorated, as the oldest type was manufactured from glass, was a melting surfaces of sand with soda or caustic potash granules, this was the porcelain used to make beads, engravings and small ornaments in ancient times, and in the second millennium BC, the first real receptacles of glass appeared , the Romans were able to pour the glass windows, without sufficient serenity, did not increase its use for the admission of light, without exposure to the weather conditions. The glass flows in the form of a flat board, perhaps conducted by the rolling process is hot, so that it becomes thinner thicker. In spite of the presence of glass in a small number of old churches, dating to the seventh century, but the widening panels of transparent glass, it did not become common only in the seventeenth century.
Glass production
It took vitrification processes (glass) old industry into small frames for windows, for the installation of this glass (coronary) or (Normandy) on them, and has been retained by some (bull's eye) distinctive in its center, as a different use of the penis. The alternative process for the production of (broad glass) was based on the swing of the ball, even swells and turns into a cylindrical shape, with a length of about one and a half meters, a diameter of about 45 cm. Then the parties still make their roller length, then resurfacing in an oven Mnasp.taatdmn first processes for the production of glass: Pour a slab of glass and then Derflth and polished, or inflatable ball of the glass, and then recycled in the spindle movement on the rod tip with attribution on the surface of the cool smooth even flatten the form of a tablet or take the form of the disc, and polished by flame and soften the surface. Cups and industry are the introduction of the glass ball, which is still molten in the mold and recycled it shall take the form template, and then cooled. After removing the party cup is ready.
The last method has been, along with other sophisticated way it depends on mechanization, in use until the early twentieth century, when the two methods was reached two other important issues:
Way Petersburg
Method (Vurko) in 1904 and the way (Pittsburgh) in 1926 and relies both methods to pull a strip of glass vertically from the glass furnace, through sintering furnace (annealing) by dolphins asbestos managed engines, the maintenance of the tape from the upper tip Once coolness to the point enough, after several feet of the top of the oven. The annealing process allows the glass cools slowly specified rate, and is slowly cooling is necessary to avoid the stresses arising from the rapid surface cooling. It features a glass output Bchwevih, and its surfaces polished hardwood, with some distortion or defects.
I was getting on the glass polished slab above methods, the Bderflh molten glass from the furnace, in the form of a continuous tape, but it was wrong glass plates, having marks (scars) to its surface, as a result of contact between the glass and dolphins. So it was imperative to remove these signs Baltgelekh and refinement in order to obtain two surfaces parallel to the glass plate to achieve visual completeness (good optical properties) of the final product. And, of course, fails to exhaust an estimated 20% of the grinding, polishing operations, as it was difficult in the past boyfriends glass of air bubbles.
Buoyancy method
Since the advent of flotation process at the hands of the company (Pilkington) British in 1959, it has become the primary method used in the entire world for the manufacture of flat glass, and had to be before it, pour any flat slab of glass, then Derflth and polished to get rid of the warp and not to the equator.
The buoyancy depends on moving the strip of glass widths up to 33 meters out of the melting furnace method, and then be floated on the surface of the bath (bath) of molten tin. And retains the tape in an atmosphere is controlled chemical composition, at elevated temperature, for a period of time sufficient to flush positions irregular, and even become Alstin two levels and parallel. Featuring the surface of the resulting glass full Balastewae, as a result of the equator similar to the surface of the molten tin bath.
Being strip cooling with a driven cross-tin molten bath, until it becomes hardened surfaces enough for the passage of the tape through the sintering stage, without leaving dolphins marks (scars) on the bottom surface of the bar, featuring glass output in this way regularly fish and shine its surfaces, without the need for grinding or refine.
After seven years of hard work later, and after 14 months of operation is successful factory built industrial full size, costing a hundred thousand pounds, every month from this month, the first glass panels successful appeared, and then manufactured in this way, Butkhan 6 mm. This fish has been determined by an automatic manner, as a result of natural forces acting on the lava buoyancy, which is a good phenomenon, it needs 50% of high-quality glass market, to this fish.
But to take full advantage of the method of buoyancy, require control and control in the tape thickness of the product, which is given by the company (Pilkington) interest, to be managed, two years after the emergence of this method of producing glass thickness of 3 mm was achieved by stretching the tape gently, and in a way is controlled where, so that negated the existence of any distortions in the resulting panels.
And then be able to grow thicker slabs during the next three years, by reducing elongation suffered by the molten glass in the bathroom of buoyancy, even given increased thickness, has a range of fish currently available from 4 mm to 25 mm from the appropriate glass for construction purposes, and thickness of 2.5 mm for other purposes. [1]
Glass industry for Muslims
Muslims took care of the medieval glass industry and developed; and after he learned the methods of manufacture of the countries conquered, such as Egypt and Syria, Iraq, Iran, and it was because of their need to glassware used in perfumes, drugs, and lighting, and drinking, and others.
The glass consists of a mixture of sand (silica), potash and soda, where smelted together even turn into a liquid and well mixed. When cooled to the degree of flexibility, there is a ratio of the viscosity, which facilitates the formation. It is a glass by a long metal tube with a wooden Mbasm to protect the worker from the tube, where temperatures dipped into the liquid and raises the tip piece pain molten glass. The worker blow glass tube block and converted into a small bubble first and grow with continued blowing. And then form the bubble as the manufacturer wants, it makes them a bottle or a jug or cylinder or otherwise.
The decoration is implemented in different ways, including pressure on pots way is still soft, as well as tweezers manner, or in a way, "addendum" They are past the filaments of glass on the walls of the pots, a soft, or paste holder of glass that Lena is still, and may be colored and is so other ways.
The old Muslims making many types of glassware; Vouseltna these different forms of group dating back to the second or third century AH. This glassware dating back to the third century, this Cruet made Romania the way back to the second century the era of the Abbasid state, but so much has been decorated in a way, "addendum" in Fatimid Egypt during the fifth century, and the pitcher is due to the third century of the State Abbasid, as we received this vase Mamluk era. Vohtha magnificent has supplied colorful thread made of glass, but this bottle Once upon Hull polygon and carried out the template and decorated her neck by adding glass filaments which is from the eighth century.
This is part of a vase Fatimid era, has been decorated with Kufic writing with the opposite objects due to the fifth century AH, but this bottle and it is those Almekhalh rock crystal, it has Zachrvata machining and rinsing in Fatimid Egypt during the fifth century. The crystal glass is coupled to Khaltth heavy elements such as cobalt and is characterized by high density.
These are some of the glass weights allocated to the perfume or medical fluid from the second century of the Umayyad era, and making the Muslim Arabs balances and cymbals of the glass also, this is equivalent to the weight of the balance of pounds due to the year 129 for Migration. This is the weight fils early Umayyad period, but these cymbals it is the era of "Dear God," the Fatimid caliph, and the weight of the reign of Sultan Bey in 893 of migration.
Muslims also excelled in making Almhkawat; and so to illuminate the mosques, houses and so on, have been mentioned in the Holy Qur'an: God is the Light of the heavens and the earth, such as light Km_kah the lamp in a bottle} [Nur: 35], and we got a number of Almhkawat Mamluk Camouflaged age enamel and decorative have copies as well as the decorative plants. These niche as the Sultan of "good" has Muht enamel, and decorated with Quranic writings of cursive and floral decoration very creative. This is also from the reign of Sultan "good", it has been decorated with floral motifs only minutes with skill and mastery.
The name of this niche Prince "Haikho" legs of the Mamluk Sultan al-Nasir "Mohammed bin Kalawoon", and includes with its beautiful cursive writing "RNC Grail" which refers to the function of sommelier; where is the "functional Alrnok" feature of the Mamluk era attributes.
Muslim Arabs used the glass in the windows decoration as well; as proficient in the stained glass industry in plaster. The industry is going through several stages; the beginning of drawing on the decorative plaster units, then the discharge phase begins punching any of these units to be Tashagaha glass. And finally begin installing various pieces of glass sizes and colors from behind the stage and prove the liquid plaster.
What this method inherited continues to produce our decorative panels diverse forms of light radiate from a state of joy and fascination, is apparent in the windows of various Islamic buildings. As it used by the churches in Egypt, also for decorating and making beautiful colored windows. Muslims also used glass mosaic decorations in the work; and this clearly shows in the Umayyad Mosque in Damascus, which includes decorations exquisite landscapes, is a mosaic of this mosque, the oldest form of mosaic glass after the Islamic Dome of the Rock.
Glass structure
Glass industry
As in other solid materials are not crystalline, the ionic composition of the glass - not the atomic structure because the glass contains no atoms - that does not contain any corresponding to a transition, but due to the characteristics of chemical bonding, the glass may possess some degree of short-term rate of regularity to the atomic polygons positional nearby but they do not continue in the glass on the long term.
Glass makes heating way to high temperatures even get a pasty state of the alloy and then are molding the paste operation, according to the shape you want to get it, and there are many factors that must be considered, but this is the general way. Where the glass maker mixing specific amounts of sand, lime, soda and other items to give to some of the properties of glass own. And other components can be composed of aluminum oxide and white arsenic. The mixture is heated in an oven until it becomes sticky mass of thick liquid. The formation of small blocks becomes easy Takhadd from the oven and when cool becomes glass body formed in them. Millions of tons of sand are used each year for the manufacture of glass. However, there are special types of glass manufactured without using the sand Mtalega.uan many ways, such as drag-and-rolling mill and other types of industries vary depending on the clay soil whenever manufacturer speed up the heating was fragile, so you must slow down the heating process to bear and to be solid
Types of Glass
Glass can be divided in terms of chemical composition into three types:
Glass soda and lime: constitutes more than 90% of the glass used: It contains sodium salts of sodium carbonate and a high percentage.
Glass leaden crystal: a glass iridescent, high-density and has a high light refractive index, is used in the antiques and accessories industry and the Pleiades and how old is used to preserve food and drink Due to the interaction of the lead with food longer in use for the threat to human health.
Quartz (silica glass): It contains silica by 96%, making it the need to high temperatures to be manufactured, is characterized by high resistance to temperature, which makes it suitable for the manufacture of thermometers and furnaces.
As it can be broken glass also in terms of physical therapy into two types:
Plasticized glass:
Tempered glass: where is heated to a certain temperature and then cooled rapidly by exposing the glass surface to air currents Pard.l is a distinguished from ordinary annealed glass, including the following:
- * Tempered glass can withstand mechanical shocks more than the average bear to 5-7 times stained glass. When the glass break down as a result of severe shock, it turns into a large number of small fragments that do not injure or hurt anyone (that's why this so-called glass Tempered safety glass). Unlike Tempered Glass, the ordinary glass shattered when they broke into sharp fragments hurtful extremely harmful.
- * As Tempered glass can withstand a big difference between the scores of internal and external temperatures, up to 300 degrees Celsius, while these differences do not exceed 70 degrees Celsius in the ordinary annealed glass, thereby exposing it to break directly.
It is common methods for the manufacture of glass are mixing a large amount of sand with small amounts of lime and soda, and then heated to a high temperature of more than Al 1100 ° C, until it becomes a high liquid paste viscosity, it is then machined mechanical, manual methods, and then cooled to be glass.
And it is a soda-lime glass (flat glass): It is most commonly used glass, which accounts for more than the 90% of the total glass used in the world. The borosilicate glass which is called glass Albaerks and Alkimuks It contains silica (80%) and alkali (4%) and alumina (2%) and boric oxide (13%). This is what gives it a hardness that more than three times the normal flat glass.
The molten glass silica quartz It contains silica by (96%) and is characterized by its resistance to shock, but it was too expensive.
The most important characteristic of the glass in terms of its manufacture is to his wife, which depends on the temperature, so a pure silica glass high Wife and requires very high temperatures to get rid of bubbles in it.
And this thing makes it pure silica glass industry is very costly. So, for reasons of scientific needs to be weakened in order to facilitate silica glass manufactured economically. From our experience, it is clear that the alkaline metal oxides are the best way to achieve this.
And the secret lies in that that each atom Silicon linked only four atoms of oxygen and that any atoms additional oxygen works disrupting the formation of coherent and strong component of silicone - oxygen - silicon, so it has become easy to change the installation of silica glass and make it more mobile, using oxides of alkali metals.
These oxides and alkaline melting of the most important factors used in the glass industry, minerals, and more of these oxides are used soda, which is the cheapest price, has been used other oxides of alkaline metals for this purpose (such as Albotaciomwalleciom ... etc).
There are types of glass used in industries such as glass microwave sensitive to light.
Albersbks [edit]
Is Mkthor (polymer) Methyl Methacrylate, its trade name (in the US) is "to Osaat," There is also a brand name is another "Blixi Glass." Featuring Alblixi Glass excellent optical properties, which are suitable for the manufacture of glasses and Aladsatuadsat cameras. As used in optical ads in the streets, and makes them heavy duty shocks glass so fit for Auto Insurance.
Safety glass [edit]
Accompanied Alttoraltknulogi and permanently so-called factors of safety that will protect workers and the work that one glass, hazardous substance and the results of their use have proved dangerous, especially that glass is generally broken into large, sharp cutting parties capable of harming a person howsoever put the accident, so it was the end of the safety glass It is to reduce the gravity of the glass and make it crashed in the form of a small, soft parts is sharp and detached without being strewn around the scene.
The safety glass is made in one of two ways, put to its creditors, "plastic" thin layer between two sheets Zjagiyn, or strengthening glass plates processed by thermal shock. It was the French chemist Edouard Benedict first to make safety glass, so while riding in 1909 chip Alceleoleod between two sheets of glass. Safety glass has been used in the vast interfaces and in a wide range in the automotive world, where the traffic accidents claiming many lives because of the glass.
The discovery of safety glass
Fells French scientist Benedict error bottle containing a substance collodion, a substance used to heal wounds and photography, from the shelf to the earth, the world and noted that the bottle had been shattered, but remained one piece and did not disintegrate, Vdhish the result, it noted moreover that the material collodion left after evaporated thin crust on the glass, she kept him entwined with some of some of that.
Read this world later that a large number of injuries occur due to volatilization of fragments of the front car glass on impact accident occurs, and the cars were at the time at the beginning of the past, remembered his mistake and material collodion, FALVEY a panacea, Since then, came into existence glass Secretary, stainless for breaking and crashing.
Budget vehicles in the glass
There are elements and chemical compounds necessary balance in the glass manufacturing process known forms and types according to use, including:
1. Lime: is a form of calcium carbonate stone mixture is added to the glass and after grinding to give some of the properties of glass. It uses calcium and dolomitic lime in large quantities with sand and calcium carbonate.
2. Lead oxide is one of the main components of glass types Zrani which is characterized by a high coefficient of refraction of light, usually include a large proportion of potash (Glass gives luster and shine at the same time is resistant to electricity and heat).
3. boric oxide reduces the degree Wife silica without increasing the heat relaxes, with the addition of a small amount of corundum maintains the transparency of the glass, and makes it more resistant to temperature (Albaerks), which are used in bakeries tools and devices laboratory Alonanwib industry for its ability to resist industry sudden temperature changes and unsustainable chemicals.
4. alumina and lime: This mixture is used by a large margin in the glass with (10%) of boric oxide, and a little alkali industry fiberglass.
Some approximation we can say that the glass is suitable mix of sand (silica) with some chemical additives and certain thermal conditions we get those pasty material that cools to give us a glass, and the glass of the most useful material in the world. It is made mainly of silica sand, soda and lime.
You can get different properties of the glass according to the method of preparation and its components where the glass can be constituted so that is extracted in the form of very fine yarns used in optical fiber manufacturing, or can be formed of pasty case and earns pliancy to pour into molds to give it the final shape as a mirror of the telescope weighing up several tons and it can be increased hardness or cruelty to become stronger than steel and more fragile than paper with the possibility of getting it many colors and shapes.
Mineral glass in the future service
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