White Paper on Duration
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Wikipedia
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book end paper, conservation paper, laminated worktops, toilet tissue, or currency and security paper, or in a number of industrial and construction processes.
The paper making process developed in east Asia, probably China, at least as early as 105 CE, by the Han court eunuch Cai Lun, although the earliest archaeological fragments of paper derive from the 2nd century BCE in China. The modern pulp and paper industry is global, with China leading its production and the United States following.
The oldest known archaeological fragments of the immediate precursor to modern paper date to the 2nd century BCE in China. The pulp paper making process is ascribed to Cai Lun, a 2nd-century CE Han court eunuch.
It has been said that knowledge of paper making was passed to the Islamic world after the Battle of Talas in 751 CE when two Chinese paper makers were captured as prisoners. Although the veracity of this story is uncertain, paper started to be made in Samarkand soon after. In the 13th century, the knowledge and uses of paper spread from the Middle East to medieval Europe, where the first water-powered paper mills were built. Because paper was introduced to the West through the city of Baghdad, it was first called bag datikos. In the 19th century, industrialization greatly reduced the cost of manufacturing paper. In 1844, the Canadian inventor Charles Fenerty and the German inventor Friedrich Gottlob Keller independently developed processes for pulping wood fibres.
Before the industrialisation of paper production the most common fibre source was recycled fibres from used textiles, called rags. The rags were from hemp, linen and cotton. A process for removing printing inks from recycled paper was invented by German jurist Justus Claproth in 1774. Today this method is called deinking. It was not until the introduction of wood pulp in 1843 that paper production was not dependent on recycled materials from rag pickers.
Duration may refer to:
- The amount of time elapsed between two events
- Duration (music) – an amount of time or a particular time interval, often cited as one of the fundamental aspects of music
- Duration (philosophy) – a theory of time and consciousness first proposed by Henri Bergson
- Duration (project management) – the number of calendar periods for the completion of a project in project management
- Bond duration – the weighted average time until the various cash flows from a bond are received.