Many newsprint , toilet paper and facial tissue grades commonly contain percent deinked pulp and in many other grades, such as lightweight coated for offset and printing and writing papers for office and home use, DIP makes up a substantial proportion of the furnish. The pulping liquor is easily recovered by distillation. The reason for using a solvent is to make the lignin more soluble in the cooking liquor. Most common used solvents are methanol , ethanol , formic acid and acetic acid often in combination with water.
Research is under way to develop biopulping biological pulping , similar to chemical pulping but using certain species of fungi that are able to break down the unwanted lignin, but not the cellulose fibres. This could have major environmental benefits in reducing the pollution associated with chemical pulping. The pulp is bleached using chlorine dioxide stage followed by neutralization and calcium hypochlorite. The oxidizing agent in either case oxidizes and destroys the dyes formed from the tannins of the wood and accentuated reinforced by sulfides present in it.
Steam exploded fibre is a pulping and extraction technique that has been applied to wood and other fibrous organic material. The pulp produced up to this point in the process can be bleached to produce a white paper product.
The chemicals used to bleach pulp have been a source of environmental concern, and recently the pulp industry has been using alternatives to chlorine , such as chlorine dioxide , oxygen , ozone and hydrogen peroxide. Non-wood pulp made from rags, or from linters short fibers discarded by the textile industry , is still manufactured today mostly as a pricey product perceived as being of better quality, especially for the art market and so-called "archival" paper.
The modern source fiber is most often cotton, with a much higher value given to paper made from linen, hemp, abaca , kozo or other fibers. Today, some people and groups [ citation needed ] advocate using field crop fibre or agricultural residues instead of wood fibre as being more sustainable. There is enough straw to meet much of North America's book, magazine, catalogue and copy paper needs. Agricultural-based paper does not come from tree farms.
Some agricultural residue pulps take less time to cook than wood pulps. That means agricultural-based paper uses less energy, less water and fewer chemicals. Pulp made from wheat and flax straw has half the ecological footprint of pulp made from forests. Hemp paper is a possible replacement, but processing infrastructure, storage costs and the low usability percentage of the plant means it is not a ready substitute.
However, wood is also a renewable resource, with about 90 percent of pulp coming from plantations or reforested areas. Nonwovens are in some applications alternatives to paper made from wood pulp, like filter paper or tea bags.
Market pulp is any variety of pulp that is produced in one location, dried and shipped to another location for further processing. In it accounted for about 55 million metric tons of market pulp. Air dry pulp is the most common form to sell pulp. This is pulp dried to about 10 percent moisture content. The reason to leave 10 percent moisture in the pulp is that this minimizes the fibre to fibre bonding and makes it easier to disperse the pulp in water for further processing to paper.
Roll pulp or reel pulp is the most common delivery form of pulp to non traditional pulp markets. Fluff pulp is normally shipped on rolls reels. This pulp is dried to 5—6 percent moisture content.
At the customer this is going to a comminution process to prepare for further processing. Some pulps are flash dried. This is done by pressing the pulp to about 50 percent moisture content and then let it fall through silos that are 15—17 m high. Gas fired hot air is the normal heat source. The temperature is well above the char point of cellulose , but large amount of moisture in the fibre wall and lumen prevents the fibres from being incinerated.
It is often not dried down to 10 percent moisture air dry. The bales are not as densely packed as air dry pulp. The major environmental impacts of producing wood pulp come from its impact on forest sources and from its waste products. The impact of logging to provide the raw material for wood pulp is an area of intense debate.
Modern logging practices, using forest management seek to provide a reliable, renewable source of raw materials for pulp mills. The practice of clear cutting is a particularly sensitive issue since it is a very visible effect of logging. Reforestation , the planting of tree seedlings on logged areas, has also been criticized for decreasing biodiversity because reforested areas are monocultures. Logging of old growth forests accounts for less than 10 percent of wood pulp,  but is one of the most controversial issues.
The process effluents are treated in a biological effluent treatment plant , which guarantees that the effluents are not toxic in the recipient. Mechanical pulp is not a major cause for environmental concern since most of the organic material is retained in the pulp, and the chemicals used hydrogen peroxide and sodium dithionite produce benign byproducts water and sodium sulfate finally , respectively.
Chemical pulp mills, especially kraft mills, are energy self-sufficient and very nearly closed cycle with respect to inorganic chemicals. Bleaching with chlorine produces large amounts of organochlorine compounds, including dioxins. The kraft pulping reaction in particular releases foul-smelling compounds. The hydrogen sulfide reagent that degrades lignin structure also causes some demethylation to produce methanethiol , dimethyl sulfide and dimethyl disulfide. These same compounds are released during many forms of microbial decay, including the internal microbial action in Camembert cheese , although the kraft process is a chemical one and does not involve any microbial degradation.
Talking about these topics can help you figure out how to approach searching for and finding good sources. We also know how and when to refer you for a follow-up appointment with the Reference Assistance and Instruction department. You Get What You Give: Reflections on the Dissertation Writing Retreat May 25, Creating a Culture of Writing: University of Louisville Writing Center.
How are the papers I'm asked to write in my major different from those in English , , and courses? I want to get started writing early, but how do I begin? How do I get started writing a personal statement? I have a lot to say, but how can I organize my thoughts? How can I learn how to write in a new genre for example, personal statement, resume, or literature review? Academic journals add credibility and professionalism to a paper.
They work well for both humanities and scientific papers. Another great way to access academic papers is Google Scholar. It is a search tool that finds scholarly articles—academic journals, patents, theses, court proceedings, and more. Google Scholar displays how many times an academic piece of literature was cited, which is a rough numerical indicator of how influential the research was.
Google Scholar also has link under each posting to help you find related articles. Some fields such as the humanities prefer their students use books for sources rather than websites, since books typically contain more detailed information and perhaps more in-depth thinking than websites do.
Books can be found on your school or public library website. Type in keywords related to your topic in the search field, and see what kinds of literature comes up. Write down the call number of the book so that you can find it within your library. Google has another service, Google Books, that will help you find books related to your topic. Just type your research topic into the field and Google Books will provide you with a list of relevant books.
Once you click on a book you like, Google Books will give you a preview of the book and information related to buying the book or finding it in your library.
Another reason why Wikipedia should not be cited in an academic research paper is that it aims to be like an encyclopedia–a source of reference information, not scholarly research or primary or secondary sources. One must delineate between general reference for general knowledge and scholarly sources for in-depth knowledge and research.
You may get lucky and get great sources, or you may get stuck with less credible sites that leave your professor wondering where you got such information. Learning how to evaluate sources for research paper writing is a key .
Finding Sources--explanation Using sources to support your ideas is one characteristic of the research paper that sets it apart from personal and creative writing. Sources come in many forms, such as magazine and journal articles, books, newspapers, videos, films, computer discussion groups, surveys, or interviews. The standard bibliography resource for students from high school to graduate school has been Kate Turabian's Manual for Writers of Research Papers, Theses, and Dissertations, which is an adaptation of the Chicago Style Manual. When listing sources in a bibliography at the end of a research paper, precision and.
Collecting sources for a research paper can sometimes be a daunting task. When beginning your research, it’s often a good idea to begin with common search engines, like Google, and general descriptions like you can find on Wikipedia. Print sources are the most traditional form of research paper sources. Books, journals, newspapers, magazines and textbooks are all print resources that typically are found in libraries and bookstores.