Saturday, June 1, 2019

paper :: essays research papers

Paper has a long history, beginning with the ancient Egyptians and go on to the present day. For thousands of years, hand-made methods dominated and then, during the 19th century, paper production became industrialised. Originally intended purely for writing and printing purposes, a wide variety of paper grades and uses atomic number 18 now available to the consumer Of all the writing and drawing materials that people have employed down the ages, paper is the most widely used around the world. Its be derives from papyrus the material used by the ancient Egyptians, Greeks and Romans. Papyrus, however, is only one of the predecessors of paper that together are known by the generic term tapa and are mostly made from the inner bark of paper mulberry, fig and daphne.Tapa has been found extensively in nearly all cultures along the equatorial belt and is made by what is possibly the oldest papermaking technique one still practised in some parts of the Himalayas and South East Asia. I ndeed, recent archaeologic excavations in China have revealed some of the oldest tapa paper ever found which shows that paper was being produced in China before western records began.The tapa technique involves cooked bast, which is flattened with a wooden hammer to form a thin, fibrous layer and then dissolved in a vat with wet to make a pulp. A screen consisting of a wooden frame with a fabric base is then laid in a piss or big basin and floats with the fabric just under the surface of the water. The papermaker then pours the quantity of pulp needed to make one sheet into this be adrift mould and spreads it evenly, by hand, across the surface. The screen is then carefully lifted out of the water, allowed to drain off and a sheet of paper forms on the wire. at one time the water has dripped off, the screen is placed in the sun or near a fire to dry. When dry, the sheet easily peels off and, apart from possible smoothing, requires no further treatment. This technique has two ba sic drawbacks. Firstly, a separate screen is needed for each new sheet, and is only available for use again afterwards the last sheet has dried. And secondly, an increase in production can soon lead to a shortage of raw material, since fresh bast is not endlessly available everywhere in the required quantity.The fibres normally used for textiles, like flax and hemp, also served as substitutes for bast.

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