glass

Glass Glass is a hard, non-crystalline and solid material normally fragile and transparent common in our daily life. It is made of about 75% of sand (silicates), soda ash and limestone and can fuse together at high temperature; then they are cooled rapidly, not having enough time to form a crystalline regular structure and forming a rigid structure. Depending on the final use and application the composition of the glass and cooling rate will vary to achieve the adequate properties for the specific application. Glass is used for architecture application, illumination, electrical transmission, instruments for scientific research, optical instruments, domestic tools and even textiles. · Properties and characteristics -Solid and hard material -Fragile and easily breakable into sharp pieces -Transparent to visible light -Inert and biologically inactive material -100% recyclable

History

· The glass in antiquity

The first objects made of glass were beads, and necklaces. The theory was that Asian artisans established the manufacture of glass in Egypt. the production of glass flourished in Egypt and Mesopotamia in 1200 B.C. and later almost ceased completely, during several centuries.

In the first one mentioned (Egypt) the glass was clear, coloring of blue and green. During the Hellenistic times, Egypt became the main supplier of glass objects from the royal courts. However, it was in the Phoenician coast where it developed the important discovery of glassblowing in the first century. BC During the Roman glassmaking spread throughout the Empire from Rome to Germany.

· The glass in the Middle Ages

In the north of Europe and Britain, it continued producing utilitarian objects made of glass. The Waldglas, common glass type (in German, 'Glass Forest') continued to be producing in Europe until the modern era. However, the most important production of this material during the Middle Ages were the glass mosaics in the Mediterranean Europe and the windows in the north. In the sixth century document refers to windows in churches, although the first date from the eleventh century preserved. The art of glass manufacturing declined at the end of the Renaissance but recovered again in the nineteenth century.

The glass in the Islamic country flourished in the Middle East between VIII and XIV century. The ancient tradition of Sasanian glass grinding was continued by Muslim artisans who made pottery decorated in high relief, many with animal motifs, and high quality clear glass, with wheel-carved designs. In Egypt comes the discovery of glazed with bright colors, metallic effects, both in ceramic and glass.

<span style="font-family: 'Comic Sans MS',cursive;">· From the Renaissance to the eighteenth century

<span style="font-family: 'Comic Sans MS',cursive;">Although the glass was already been made in Venice since the tenth century. The most important contribution was the development of Venetian glass hard.

<span style="font-family: 'Comic Sans MS',cursive;">All the European glass manufacturers, attempted to copy the techniques, material and furnishings.

<span style="font-family: 'Comic Sans MS',cursive;">The Italian influence declined in the seventeenth century, the emergence in Germany and England, new methods for the manufacture of glass

<span style="font-family: 'Comic Sans MS',cursive;">Type of Glasses

<span style="font-family: 'Comic Sans MS',cursive;">Because of their chemical, physical, and in particular optical properties make them suitable for applications such as flat glass, container glass, optics and optoelectronics material, laboratory equipment, thermal insulator (glass wool), reinforcement materials (glass-reinforced plastic, glass fiber reinforced concrete), and glass art (art glass, studio glass).

<span style="font-family: 'Comic Sans MS',cursive;">· Commercial glass: <span style="font-family: 'Comic Sans MS',cursive;">This is the most common commercial glass and less expensive. A low percentage of other materials can be added for specific properties such as coloring. <span style="font-family: 'Comic Sans MS',cursive;">- It has light transmission appropriate to be use in flat glass in windows

<span style="font-family: 'Comic Sans MS',cursive;">- It has a smooth and nonporous surface allows to be easily cleaned

<span style="font-family: 'Comic Sans MS',cursive;">-Does not allow light at a wavelength of UV light to pass.

<span style="font-family: 'Comic Sans MS',cursive;">-The disadvantage of soda-lime glass is that is not resistant to high temperatures and sudden thermal changes. Some of the use of soda-lime glass is primarily used for bottles, jars, everyday drinking glasses, and window glass.

<span style="font-family: 'Comic Sans MS',cursive;">· Lead glass:

<span style="font-family: 'Comic Sans MS',cursive;">- In moderate amounts lead increases durability;

<span style="font-family: 'Comic Sans MS',cursive;">- In high amounts it lowers the melting point and decreases the hardness giving a soft surface;

<span style="font-family: 'Comic Sans MS',cursive;">- In addition it has a high refractive index giving high brilliance glass.

<span style="font-family: 'Comic Sans MS',cursive;">These two last properties make it appropriate for decorating purposes.

<span style="font-family: 'Comic Sans MS',cursive;">· Borosilicate glass: <span style="font-family: 'Comic Sans MS',cursive;">Boron gives greater resistance to thermal changes and chemical corrosion. <span style="font-family: 'Comic Sans MS',cursive;">It is suitable for industrial chemical process plants, in laboratories, in the pharmaceutical industry, in bulbs for high-powered lamps, etc. Borosilicate glass is also used in the home for cooking plates and other heat-resistant products. It is used for domestic kitchens and chemistry laboratories. <span style="font-family: 'Comic Sans MS',cursive;">· Glass art:

<span style="font-family: 'Comic Sans MS',cursive;">From the 19th century, glass started to become significant branches of the decorative arts, like colored vases and similar piece.

<span style="font-family: 'Comic Sans MS',cursive;">· Recently develops:

<span style="font-family: 'Comic Sans MS',cursive;">-Safety glass constructed of two pieces of plate glass join by a plastic to prevent the glass from scattering when broken.

<span style="font-family: 'Comic Sans MS',cursive;">-Fiberglass made from molten glass formed into continuous filaments that is used for fabrics or electrical insulation.

<span style="font-family: 'Comic Sans MS',cursive;">-Foam by trapping gas bubbles in glass.

<span style="font-family: 'Comic Sans MS',cursive;">Production <span style="font-family: 'Comic Sans MS',cursive;">There are several ways of doing glass here we mention three of them: <span style="font-family: 'Comic Sans MS',cursive;">1. Sand (SiO2 silica) <span style="font-family: 'Comic Sans MS',cursive;">In its pure form it exists as a polymer, (SiO2)n.

<span style="font-family: 'Comic Sans MS',cursive;">2. Soda ash (sodium carbonate Na2CO3) <span style="font-family: 'Comic Sans MS',cursive;">Normally SiO2 softens up to 2000°C, where it starts to degrade (at 1713°C most of the molecules can already move freely). Adding soda will lower the melting point to 1000°C making it more manageable. <span style="font-family: 'Comic Sans MS',cursive;">3. Limestone (calcium carbonate or CaCo3) or dolomite (MgCO3) <span style="font-family: 'Comic Sans MS',cursive;">Also known as lime, calcium carbonate is found naturally as limestone, marble, or chalk. The soda makes the glass water-soluble, soft and not very durable. Therefore lime is added increasing the hardness and chemical durability and providing insolubility of the materials.

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<span style="font-family: 'Comic Sans MS',cursive; font-size: 16pt; line-height: 115%;">Paragraph. <span style="font-family: 'Comic Sans MS',cursive;">The use of glass in architecture in Caracas.

<span style="font-family: 'Comic Sans MS',cursive;">As we know glass <span style="background-color: #ffff00; font-family: 'Comic Sans MS',cursive;">has been used in architecture for a long time. <span style="font-family: 'Comic Sans MS',cursive;"> <span style="background-color: #ffff00; font-family: 'Comic Sans MS',cursive;"> Nowadays <span style="font-family: 'Comic Sans MS',cursive;">, we can see the different uses of it in architecture. Let’s take as an example the case of Caracas. <span style="font-family: 'Comic Sans MS',cursive;">Today the use of glass in Caracas is varied; it can be found in buildings, homes, churches, shopping malls and in other different projects to cover the entire facade or maybe just to let light get into the space. <span style="font-family: 'Comic Sans MS',cursive;">In this way, we could see the Torre Polar where glass has been used over the all facade unlike the Hotel Gran Meliá Caracas where it is used just to give that little entry of light that the space needs. <span style="background-color: #ffff00; font-family: 'Comic Sans MS',cursive;">Also, it is possible to analyze the use of glass in the Centro Comercial Millennium Mall or Quinta Mi Cerrito where the sense of its use is just to give beauty to the project in combination with other materials, unlike El Cubo Negro, that uses Curtain-Walls in all its facades as the only material. <span style="font-family: 'Comic Sans MS',cursive;">Finally, we can see that glass in Caracas’s architecture has been used in many different ways, in different senses and combinations that makes each project unique.



Hotel Gran Meliá de Caracas



<span style="display: block; font-family: 'Comic Sans MS',cursive; text-align: center;">Quinta Mi Cerrito



<span style="display: block; font-family: 'Comic Sans MS',cursive; text-align: center;">Centro Comercial Millennium Mall

<span style="display: block; font-family: 'Comic Sans MS',cursive; text-align: center;">Cubo Negro de Caracas



<span style="display: block; font-family: 'Comic Sans MS',cursive; text-align: center;">Torre Polar