沥青 – 也称为沥青或焦油 – 是一种黑色,油性,粘稠形式的石油,是分解植物的天然存在的有机副产物。它具有防水和易燃性,至少在过去的4万年中,这种非凡的天然物质已被人类用于各种任务和工具。现代世界中使用了许多加工类型的沥青,设计用于铺设街道和屋顶房屋,以及柴油或其他瓦斯油的添加剂。沥青的发音是英国英语中的“BICH-eh-men”和北美的“by-TOO-men”。天然沥青是最厚的石油形式,由83%的碳,10%的氢和较少量的氧,氮,硫和其他元素组成。它是一种低分子量的天然聚合物,具有显着的随温度变化而变化的能力:在较低温度下,它是刚性和脆性的,在室温下它是柔性的,在较高温度下沥青流动。沥青沉积物在世界各地自然发生 – 最着名的是特立尼达的沥青湖和加利福尼亚的La Brea Tar Pit,但在死海,委内瑞拉,瑞士和加拿大阿尔伯塔省东北部都有大量沉积物。这些沉积物的化学成分和稠度差异很大。在一些地方,沥青自然地从陆地来源挤出,而在另一些地方,它出现在可以硬化成土堆的液体池中,还有一些从水下渗出,从沙滩和岩石海岸线上冲刷成沥青。在远古时代,沥青被用于大量的东西:作为密封剂或粘合剂,如建筑砂浆,香料,以及在盆,建筑物或人体皮肤上的装饰颜料和纹理。该材料还可用于防水独木舟和其他水上运输,以及在古埃及新王国末期的木乃伊化过程中。

英国谢菲尔德大学论文代写:沥青

Bitumen – also known as bitumen or tar – is a black, oily, viscous form of petroleum that is a naturally occurring organic by-product of the decomposition of plants. It is waterproof and flammable, and at least for the past 40,000 years, this extraordinary natural substance has been used by humans for a variety of tasks and tools. Many processing types of bitumen are used in the modern world, designed to lay street and roof houses, as well as additives for diesel or other gas oils. The pronunciation of asphalt is “BICH-eh-men” in British English and “by-TOO-men” in North America. Natural asphalt is the thickest form of petroleum consisting of 83% carbon, 10% hydrogen and lesser amounts of oxygen, nitrogen, sulfur and other elements. It is a low molecular weight natural polymer with significant ability to change with temperature: it is rigid and brittle at lower temperatures, it is flexible at room temperature, and asphalt at higher temperatures flow. Asphalt deposits occur naturally around the world – most notably the asphalt lakes of Trinidad and La Brea Tar Pit of California, but with large deposits in the Dead Sea, Venezuela, Switzerland and northeastern Alberta, Canada. The chemical composition and consistency of these deposits vary widely. In some places, bitumen naturally extrudes from land sources, while in others it appears in liquid pools that can harden into mounds, and some seep out from underwater, scouring asphalt from beaches and rocky shorelines. . In ancient times, bitumen was used in a large number of things: as a sealant or binder, such as building mortar, spices, and decorative pigments and textures on pots, buildings or human skin. The material can also be used for waterproof canoes and other water transport, as well as during the mummification of the late New Kingdom of Egypt.

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