...during the early 2nd century AD, possibly as early as the year 105 A.D., by the Han court eunuch Cai Lun, although the earliest archaeological fragments of paper derive from the 2nd century BC in China. The modern pulp and paper industry is global, with China leading production and the United States behind it.To make pulp from wood, a chemical pulping process separates lignin from cellulose fibers. This is accomplished by dissolving lignin in a cooking liquor, so that it may be washed from the cellulose fibers. This preserves the length of the cellulose fibers. Paper made from chemical pulps are also known as wood-free papers–not to be confused with tree-free paper. This is because they do not contain lignin, which deteriorates over time. The pulp can also be bleached to produce white paper, but this consumes 5% of the fibers. Chemical pulping processes are not used to make paper made from cotton, which is already 90% cellulose. The microscopic structure of paper: Micrograph of paper autofluorescing under ultraviolet illumination. The individual fibres in this sample are around 10 µm in diameter. There are three main chemical pulping processes. The sulfite process dates back to the 1840s, and it was the dominant process before the second world war. The kraft process, invented in the 1870s and first used in the 1890s, is now the most commonly practiced strategy. One advantage is a chemical...
Are You Proud To Be An American?
It is a great privilige to be an American. We have many rights and freedoms that other countries don't have. Most of us have grown up taking these freedoms for granted.We need to remember how fortunate we are to be American citizens.
In the United States, there is free public school education. Children can come from a poorer background and still go to school and get a good eduation. In some some countries, if you are a certain gender, race, or religion, you can't go to school.
Our military helps protect our borders. The service men and womenhelp set up governments in war torn countries. They represent the United States of America to other nations. They are the symbol of what America stands for. The military made up of almost all volunteers and their service guarantees our safety and freedom.
Religious freedom is another one of our great privileges. We don't all have to be one religion. We respect there are differences in our beliefs. Many countries persecute people of different religions and force them into their country's religion. if you have different beliefs you must worship in secret.
Our country has a Constitution that protectsour freedom and rights. The second amendment allows us to speak out against our government.in other countries you could be thrown in jail or killed for speaking out.
America celebrates peoples' differences. We have cultural diversity. Immigrants have come and settled in different regions of the country to take advantage of our rights and freedoms. Some people look at America as the Land of Oppurtunity. They believe they can find a better job and a better life for their family.
I am proud to live in the United States if my parents didn't want me to attend a private school, I could still attend a public school and get a good education. I can choose whether I want to be in the military or not . Our religious freedom allows me to worship in any religion. Our...