Questões

A Brief and Simplified Description of Papermaking

The paper we use today is created from individual wood fibers that are first suspended in water and then pressed and dried into sheets. The process of converting the wood to a suspension of wood fibers in water is known as pulp making, while the manufacture of the dried and pressed sheets of paper is formally termed papermaking. The process of making paper has undergone a steady evolution, and larger and more sophisticated equipment and better technology continue to improve it.

The Wood yard and Wood rooms

The process at Androscogging began with receiving wood in the form of chips or of logs 4 or 8 feet in length. From 6 AM to 10 PM a steady stream of trucks and railroad cars were weighted and unloaded. About 40 percent were suplied by independents who were paid by weight their logs. The mill also received wood chips from lumber mills in the area. The chips and logs were stored in mammoth piles with separate piles for wood of different species (such as pine, spruce, hemlock).

When needed, logs were floated in flumes......(1).....the wood yard.....(2).....one of the mill’s three wood rooms. There, bark was rubbed......(3)........in long, ribbed debarking drums by tumbling the logs against one another. The logs then fell into a chipper;......(4)......seconds a large log was reduced to a pile of chips approximately 1 inch by 1 inch by 1/4 inch.

The chips were stored in silos. There were separate silos for softwoods (spruce, fir, hemlock, and pine) and hardwoods (maple, oak, beech, and birch). This separate and temporary storage of chips permitted the controlled mixing of chips into the precise recipe for the grade of paper being produced.

The wood chips were then sorted through large, flat vibrating screens. Oversized chips were rechipped, and ones that were too small were collected for burning in the power house. (The mill provided approximately 20 percent of all its own steam and electricity needs from burning waste. An additional 50 percent of total electricity needs was produced by harnessing the river for hydroelectric power.)

Once drawn from the silo into the digesters, there was no stopping the flow of chips into paper. 

Pulpmaking

The pulp made at Androscoggin was of two types: Kraft pulp (produced chemically) and ground wood pulp (produced mechanically). Kraft pulp was far more important to the high quality white papers produced at Androscoggin, accounting for 80 percent of all the pulp used. Kraft pulp makes strong paper. (Kraft is German for strength. A German invented the Kraft pulp process in 1884.) A paper’s strength generally comes from the overlap and binding of long fibers of softwood; only chemically was it initially possible to separate long wood fibers for suspension in water. Hardwood fibers are generally smaller and thinner and help smooth the paper and make it less porous.

The ground wood pulping process was simpler and less expensive than the Kraft process. It took high quality spruce and fir logs and pressed them continuously against a revolving stone that broke apart the wood’s fibers. The fibers, however, were smaller than those produced by the Kraft process and, although used to make newsprint, were useful at Androscoggin in providing “fill” for the coated publication gloss papers of machines 2 and 3, as will be described later.

^(A)The chemical Kraft process worked by dissolving the lignin that bonds wood fibers together. ^(B) It did this in a tall pressure cooker, called a digester, by “cooking” the chips in a solution of caustic soda (NaOH) and sodium sulfide (Na²S), which was termed the “white liquor.” ^(C)The two digesters at Androscoggin were continuous digesters; chips and liquor went into the top, were cooked together as they slowly settled down to the bottom, and were drawn off the bottom after about three hours. ^(D) By this time, the white liquor had changed chemically to “black liquor’’; the digested chips were then separated from this black liquor. ^(E)

In what was known as the “cold blow” process, the hot, pressurized chips were gradually cooled and depressurized. A “cold liquor’’ (170°F) was introduced to the bottom of the digester and served both to cool and to transport the digested chips to a diffusion washer that washed and depressurized the chips. Because so much of the lignin bonding the fibers together had been removed, the wood fiber in the chips literally fell apart at this stage.

The black liquor from the digester entered a separate four-step recovery process. Over 95 percent of the black liquor could be reconstituted as white liquor, thereby saving on chemical costs and significantly lowering pollution. The four-step process involved (1) washing the black liquor from the cooked fiber to produce weak black liquor, (2) evaporating the weak black liquor to a thicker consistency, (3) combustion of this heavy black liquor with sodium sulfate (Na₂SO₄ ), and redissolving the smelt, yielding a “green liquor” (sodium carbonate + sodium sulfide), and (4) adding lime, which reacted with the green liquor to produce white liquor. The last step was known as causticization.

Meanwhile, the wood-fiber pulp was purged of impurities like bark and dirt by mechanical screening and by spinning the mixture in centrifugal cleaners. The pulp was then concentrated by removing water from it so that it could be stored and bleached more economically.

By this time, depending on the type of pulp being made, it had been between 3 1/2 and 5 hours since the chips had entered the pulp mill. 

All the Kraft pulp was then bleached. Bleaching took between 5 and 6 hours. It consisted of a three-step process in which (1) a mix of chlorine (Cl₂ ) and chlorine dioxide (CIO₂ ) was introduced to the pulp and the pulp was washed; (2) a patented mix of sodium hydroxide (NaOH), liquid oxygen, and hydrogen peroxide (H₂ O₂ ) was then added to the pulp and the pulp was again washed; and (3) chlorine dioxide (ClO₂ ) was introduced and the pulp washed a final time. The result was like fluffy cream of wheat. By this time the pulp was nearly ready to be made into paper.

From the bleachery, the stock of pulp was held for a short time in storage (a maximum of 16 hours) and then proceeded through a series of blending operations that permitted a string of additives (for example, filler clay, resins, brighteners, alum, dyes) to be mixed into the pulp according to the recipe for the paper grade being produced. Here, too, “broke” (paper wastes from the mill itself) was recycled into the pulp. The pulp was then once again cleaned and blended into an even consistency before moving to the papermaking machine itself.

It made a difference whether the broke was of coated or uncoated paper, and whether it was white or colored. White, uncoated paper could be recycled immediately. Colored, uncoated paper had to be rebleached. Coated papers, because of the clays in them, could not be reclaimed.

TEXT

    A library tradition is being refashioned to emphasize early literacy and better prepare young children for school, and drawing many new fans in the process.

    Among parents of the under-5 set, spots for story time have become as coveted as seats for a hot Broadway show like “Hamilton.” Lines stretch down the block at some branches, with tickets given out on a first-come-first-served basis because there is not enough room to accommodate all of the children who show up.

    Workers at the 67th Street Library on the Upper East Side of Manhattan turn away at least 10 people from every reading. They have been so overwhelmed by the rush at story time — held in the branch’s largest room, on the third floor — that once the space is full, they close the door and shut down the elevator. “It is so crowded and so popular, it’s insane,” Jacqueline Schector, a librarian, said.

    Story time is drawing capacity crowds at public libraries across New York and across the country at a time when, more than ever, educators are emphasizing the importance of early literacy in preparing children for school and for developing critical thinking skills. The demand crosses economic lines, with parents at all income levels vying to get in.

    Many libraries have refashioned the traditional readings to include enrichment activities such as counting numbers and naming colors, as well as music and dance. And many parents have made story time a fixture in their family routines alongside school pickups and playground outings — and, for those who employ nannies, a nonnegotiable requirement of the job.

    In New York, demand for story time has surged across the city’s three library systems — the New York Public Library, the Brooklyn Public Library, and the Queens Library — and has posed logistical challenges for some branches, particularly those in small or cramped buildings. Citywide, story time attendance rose to 510,367 people in fiscal year 2015, up nearly 28 percent from 399,751 in fiscal 2013.

    “The secret’s out,” said Lucy Yates, 44, an opera coach with two sons who goes to story time at the Fort Washington Library every week.

    Stroller-pushing parents and nannies begin to line up for story time outside some branches an hour before doors open. To prevent overcrowding, tickets are given out at the New Amsterdam and Webster branches, both in Manhattan, the Parkchester branch in the Bronx, and a half-dozen branches in Brooklyn, including in Park Slope, Kensington and Bay Ridge.

    The 67th Street branch keeps adding story times — there are now six a week — and holds sessions outdoors in the summer, when crowds can swell to 200 people.

    In Queens, 41 library branches are scheduled to add weekend hours this month, and many will undoubtedly include weekend story times. As Joanne King, a spokeswoman for the library explained, parents have been begging for them and “every story time is full, every time we have one.”

    Long a library staple, story time has typically been an informal reading to a small group of boys and girls sitting in a circle. Today’s story times involve carefully planned lessons by specially trained librarians that emphasize education as much as entertainment, and often include suggestions for parents and caregivers about how to reinforce what children have learned, library officials said.

    Libraries around the country have expanded story time and other children’s programs in recent years, attracting a new generation of patrons in an age when online offerings sometimes make trips to the book stacks unnecessary. Sari Feldman, president of the American Library Association, said such early-literacy efforts are part of a larger transformation libraries are undergoing to become active learning centers for their communities by offering services like classes in English as a second language, computer skills and career counseling.

    Ms. Feldman said the increased demand for story time was a product, in part, of more than a decade of work by the library association and others to encourage libraries to play a larger role in preparing young children for school. In 2004, as part of that effort, the association developed a curriculum, “Every Child Ready to Read,” that she said is now used by thousands of libraries.

    The New York Public Library is adding 45 children’s librarians to support story time and other programs, some of which are run in partnership with the city government. It has also designated 20 of its 88 neighborhood branches, including the Fort Washington Library, as “enhanced literary sites.” As such, they will double their story time sessions, to an average of four a week, and distribute 15,000 “family literacy kits” that include a book and a schedule of story times.

    “It is clear that reading and being exposed to books early in life are critical factors in student success,” Anthony W. Marx, president of the New York Public Library, said. “The library is playing an increasingly important role in strengthening early literacy in this city, expanding efforts to bring reading to children and their families through quality, free story times, curated literacy programs, after-school programs and more.”

    For its part, the Queens Library plans to expand a “Kick Off to Kindergarten” program that attracted more than 180 families for a series of workshops last year. Library officials said that more than three-quarters of the children who enrolled, many of whom spoke a language other than English at home, developed measurable classroom skills.

From: www.nytimes.com/2015/11/02

                                      What causes hunger?

      The world produces enough to feed the entire global population of 7 billion people. And yet, one person in eight on the planet goes to bed hungry each night. In some countries, one child in three is underweight. Why does hunger exist? There are many reasons for the presence of hunger in the world and they are often interconnected. Here are six that we think are important.  

      Poverty trap

      People living in poverty cannot afford nutritious food for themselves and their families. This makes them weaker and less able to earn the money that would help them escape poverty and hunger. This is not just a day-to-day problem: when children are chronically malnourished, or ‘stunted’, it can affect their future income, condemning them to a life of poverty and hunger. In developing countries, farmers often cannot afford seeds, so they cannot plant the crops that would provide for their families. They may have to cultivate crops without the tools and fertilizers they need. Others have no land or water or education. In short, the poor are hungry and their hunger traps them in poverty. 

      Lack of investment in agriculture

      Too many developing countries lack key agricultural infrastructure, such as enough roads, warehouses and irrigation. The results are high transport costs, lack of storage facilities and unreliable water supplies. All conspire to limit agricultural yields and access to food. Investments in improving land management, using water more efficiently and making more resistant seed types available can bring big improvements. Research by the UN Food and Agriculture Organization shows that investment in agriculture is five times more effective in reducing poverty and hunger than investment in any other sector. 

      Climate and weather

      Natural disasters such as floods, tropical storms and long periods of drought are on the increase – with calamitous consequences for the hungry poor in developing countries. Drought is one of the most common causes of food shortages in the world. In 2011, recurrent drought caused crop failures and heavy livestock losses in parts of Ethiopia, Somalia and Kenya. In 2012 there was a similar situation in the Sahel region of West Africa. In many countries, climate change is exacerbating  already adverse natural conditions. Increasingly, the world’s fertile farmland is under threat from erosion, salination and desertification. Deforestation by human hands accelerates the erosion of land which could be used for growing food.

      War and displacement

      Across the globe, conflicts consistently disrupt farming and food production. Fighting also forces millions of people to flee their homes, leading to hunger emergencies as the displaced find themselves without the means to feed themselves. The conflict in Syria is a recent example. In war, food sometimes becomes a weapon. Soldiers will starve opponents into submission by seizing or destroying food and livestock and systematically wrecking local markets. Fields are often mined and water wells contaminated, forcing farmers to abandon their land. Ongoing conflict in Somalia and the has contributed significantly to the level of hunger in the two countries. By comparison, hunger is on the retreat in more peaceful parts of Africa such as Ghana and Rwanda.  

      Unstable markets

      In recent years, the price of food products has been very unstable. Roller-coaster food prices make it difficult for the poorest people to access nutritious food consistently. The poor need access to adequate food all year round. Price spikes may temporarily put food out of reach, which can have lasting consequences for small children. When prices rise, consumers often shift to cheaper, less-nutritious foods, heightening the risks of micronutrient deficiencies and other forms of malnutrition.  

      Food wastage

      One third of all food produced (1.3 billion tons) is never consumed. This food wastage represents a missed opportunity to improve global food security in a world where one in 8 is hungry. Producing this food also uses up precious natural resources that we need to feed the planet. Each year, food that is produced but not eaten guzzles up a volume of water equivalent to the annual flow of Russia’s Volga River. Producing this food also adds 3.3 billion tons of greenhouse gases to the atmosphere, with consequences for the climate and, ultimately, for food production. 

Read the text below to answer the question:

ICEBERG A68a

   An enormous iceberg that is heading toward the island of South Georgia in the southern Atlantic Ocean has broken up into three large chunks. Scientists from NASA have been tracking the berg - dubbed A68a - for several weeks. It actually calved from the Larsen C ice shelf in 2017 and has been floating northwards ever since. In recent weeks, a fast-moving stream of water known as the Southern Antarctic Circumpolar Current Front has put the chunks on a trajectory that means they could run aground off the coast of South Georgia. Scientists say the three fragments are roughly 2,600 square kilometres in size. The submerged part of one chunk is 106 metres at its thickest point.

   The sheer bulk of the three iceberg chunks poses a serious threat to the wildlife of South Georgia. There could be an environmental catastrophe waiting to happen. If the three mini icebergs collide with the seabed, they could obstruct penguins and seals from foraging for fish. They could also block the route between penguin colonies and their feeding grounds during the breeding season. Scientists worry the underside of the fragments could grind the seabed near South Georgia and disrupt delicate underwater ecosystems. This could be exacerbated by the introduction of a mass of fresh water to the ecosystems as the stationary fragments melt over the summer months. 

Available at: https://breakingnewsenglish.com/2012/201229-iceberg-a68a.html Accessed on January 5th 2021.