Two major pollutants and highly dangerous Santiago , these pollutants are highly dangerous, they are the asphalt used for roads and patching, the other agent are subject to wear tires rub the wrong inflation or low speeds or have many vehicles in the fleet. Both agents have a characteristic in common use in the manufacture of petroleum products and rubber.
Chemical composition of asphalt and tires:
El asfalto es un material viscoso, pegajoso y de color negro, usado como aglomerante en mezclas asfálticas para la construcción de carreteras o autopistas . También es utilizado en impermeabilizantes . Está presente en el petróleo crudo y compuesto casi por completo de bitumen . Su nombre recuerda el Lago Asfaltites (el Mar Muerto), en la cuenca del río Jordán .
Además del sitio mencionado, se encuentra en estado natural formando una mezcla compleja de hidrocarburos sólidos en lagunas de algunas cuencas oil, as in the lake of Guanoco , the largest asphalt lake in the world ( Sucre State, Venezuela ) with 4 km ² and 75 million barrels of natural bitumen. Next in size and importance asphalt lake La Brea, on the island of Trinidad .
Despite the easy operation and excellent natural asphalt, is usually not exploited long since, obtained from the oil refinery byproduct solid in the "cracking" or fragmentation that occurs in the distillation towers, it is much economical to obtain in this way. It is similar to the procurement of gas, which is also a most undesirable byproduct in the process of obtaining gasoline and other petroleum products.
A tire, also known as cover in some regions, is a piece of toroidal rubber placed in wheels of various vehicles and machines. Its main function is to allow adequate contact for adhesion and friction with the pavement, allowing the start, braking and guidance.
The tires generally have reinforcing threads that. Depending on the orientation of these threads, are classified as bias or radial . The radial type is the standard for almost all modern cars.
The tire recycling is one of the first order problems for the environment . Today the industry have been renovated to significant advances in the process of new tire, achieving excellent rubber compounds that are reflected in the increased use of housing or helmet. But the secret in the renewed or recycling of the tires still up 80% of the care that is given in the first period of use. The main care they should seek in a new tire for this to have a renewed or optimal recycling are right pressure, good application and not exceed the load limits for which it was designed.
Tires and Rubber is the main compound.
rubber is a polymer of elastic hydrocarbon emerges as a milky emulsion (known as latex ) in the sap of various plants, but can also be produced synthetically. The main commercial source of latex are Euphorbiaceae, Hevea brasiliensis (Euphorbiaceae). Other plants containing latex, fig, euphorbias and the common dandelion. These have not been the main source of rubber, but when Germany was divided during World War II , made attempts to use such sources, before it was supplanted by the development of synthetic rubber.
Instead of origin, the central and southern America, rubber has been collected for a long time. Mesoamerican civilizations used rubber mostly from Castilla elastic. The ancient Mesoamerican ball game had where they used rubber bullets, and Pre-Columbian rubber balls were found (always in sites that were flooded with freshwater), the oldest about the year 1600 BC According to Bernal Díaz del Castillo, the English conquerors were amazed both by the great leaps that managed to balls rubber of the Aztecs , who wondered if the balls were enchanted by evil spirits.
The Maya also made a type of rubber shoe by dipping their feet into a latex mixture. The rubber was used in other contexts, such as strips to hold stone and metal tools to wooden handles, and padded handles of tools. While the ancient Mesoamerican were not vulcanization, they developed organic methods of treating the rubber with similar results, mixing the raw latex with various saps and juices of other vines, particularly Ipomoea alba .
In Brazil, the natives understood the use of rubber to make fabric waterproof. One story says that the first European to return to Portugal from Brazil with samples of such a sticker waterproof fabric, so impressed the people who were tried for witchcraft.
When samples of rubber first arrived in England was observed that a piece of material was good to erase pen writing on paper. This was the origin of the English name of the shoe material (rubber). Pieces of this material are still used for this purpose, and known as 'rubbers' (rubbers) in England, thanks also to the Americans, for whom a rubber is a condom (usually made of latex). (Americans call the piece rubber eraser.) Rubber tree initially grew only in South America, but after repeated efforts were successfully cultivated in Southeast Asian where it is now widely cultivated. More than half of the rubber used today is synthetic, but still there are several million tons of natural rubber annually.
Hypoallergenic rubber can be made from Guayule.
Recent experiments to create synthetic rubber led to the creation of Silly Putty ® (a silicone made for the amusement of children.) Natural rubber is often vulcanized , a process by which the rubber is heated and sulfur is added to improve its strength and elasticity. The vulcanization process greatly improved the durability and utility of rubber from the year 1830 . Some people use rubber as material for making clothing, perhaps on the basis that this type of clothing as a "second skin."
conclusion we can detect that the paving of the great Santiago has its environmental cost, the big culprit here is that passengers have a system of good quality, because if there were car users would walk in passenger transport is the subway or buses.
Here
contribution of the proper use of the encyclopedia http://es.wikipedia.org/wiki/Portada
Pablo Ramírez Torrejón (PD)
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