My Science School

In some relationships, one organism ends up deriving all the benefits, and the other is not harmed or helped. The remora (or suckerfish) attaches itself to the host fish, usually a shark or a large fish, with its mouth. The shark unwittingly provides protection, transportation and food scraps from prey. The remora merrily enjoys all the benefits of this association.

Then there are the parasites. A parasite associates with its host and uses the host’s resources to flourish and reproduce, harming the host in the process. The adult tapeworm is a parasite that lives in vertebrate intestines. It takes up nutrients from the food, depriving the host of essential nutrients. Ticks, fleas and head lice are also parasites.

 

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Oxpeckers are birds that eat ticks, flies and other insects from cattle and other grazing mammals. The oxpecker receives nourishment, and the animal that it grooms receives pest control. Oxpeckers are birds that are commonly found on the sub-Saharan African savanna. They can often be seen sitting on buffalo, giraffes, impalas, and other large mammals. In addition to parasite and pest removal, oxpeckers will also alert the herd to the presence of predators by giving a loud warning call.

Despite their vampiric tendencies, the oxpecker does have qualities that benefit its mammalian hosts.  As well as eating ticks and other external parasites, the oxpecker acts as a watchman for the mammals on which it happens to be situated. When danger approaches, a hissing call warns its host to a potential and nearby predatory threat thus allowing the host ample opportunity to either fight or flee.

 

 

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Clownfish live within the protective tentacles of the sea anemone. In return, the sea anemone receives cleaning and protection.

Sea anemones are attached to rocks in their aquatic habitats and catch prey by stunning them with their poisonous tentacles. Clownfish are immune to the anemone’s poison and actually live within its tentacles. Clownfish clean the anemone’s tentacles keeping them free from parasites. They also act as bait by luring fish and other prey within striking distance of the anemone. The sea anemone provides protection for the clownfish, as potential predators stay away from its stinging tentacles.

 

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Some ant species herd aphids in order to have a constant supply of honeydew that the aphids produce. In exchange, the aphids are protected by the ants from other insect predators. Some ant species farm aphids and other insects that feed on sap. The ants herd the aphids along the plant, protecting them from potential predators and moving them to prime locations for acquiring sap. The ants then stimulate the aphids to produce honeydew droplets by stroking them with their antennae. In this symbiotic relationship, the ants are provided with a constant food source, while the aphids receive protection, and shelter.

The bullhorn acacia tree that is native to Mexico, has leaves which lack essential bitter compounds that protect a tree from grazing animals or insects. Ants which live within the hollowed-out horns of the tree (called the bullhorn acacia ants) mount a speedy attack against any animal or insect that tries to harm the tree. The ants are rewarded for their services by the tree with food. In such ‘symbiotic’ relationships, two organisms of different species have intertwined lifestyles.

 

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Insects and animals play a vital role in the pollination of flowering plants. While the pollinator receives nectar or fruit from the plant, it also collects and transfers pollen in the process. Flowering plants rely heavily on insects and other animals for pollination. Bees and other insects are lured to plants by the fragrance secreted from their flowers. When the insects collect nectar, they become covered in pollen. As the insects travel from plant to plant, they deposit the pollen from one plant to another. Other animals also participate in a symbolic relationship with plants. Birds and mammals eat fruit and distribute the seeds to other locations where the seeds can germinate.

 

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Training improves performance by building up endurance, strength, flexibility and speed. This is done by improving the techniques used in a particular sport, strengthening the muscles used, improving athletes’ understanding of how their bodies are performing and giving them confidence to try even harder. There are lots of training methods, and variety can help to prevent boredom setting in.

Motor-performance fitness is defined as the ability of the neuromuscular system to perform specific tasks. Test items used to assess motor-performance fitness include chin-ups, sit-ups, the 50-yard dash, the standing long jump, and the shuttle run (a timed run in which the participant dashes back and forth between two points). The primary physical characteristics measured by these tests are the strength and endurance of the skeletal muscles and the speed or power of the legs. These traits are important for success in many types of athletics. Muscular strength and endurance are also related to some aspects of health.

There is disagreement among experts about the relative importance of health-related and motor-performance physical fitness. While both types of fitness are obviously desirable, their relative values should be determined by an individual’s personal fitness objectives. If success in athletic events is of primary importance, motor-performance fitness should be emphasized. If concern about health is paramount, health-related fitness should be the focus. Different types of fitness may be important not only to different individuals but also to the same individual at different times. The 16-year-old competing on a school athletic team is likely to focus on motor performance. The typical middle-aged individual is not as likely to be concerned about athletic success, emphasizing instead health and appearance. One further point should be made: to a great extent, motor-performance physical fitness is determined by genetic potential. The person who can run fast at 10 years of age will be fast at age 17; although training may enhance racing performance, it will not appreciably change the individual’s genetically determined running speed. On the other hand, characteristics of health-related physical fitness, while also partly determined by inheritance, are much more profoundly influenced by exercise habits.

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The cells of the raw fruit or vegetable are tightly packed and are held rigidly together by a carbohydrate called pectin which forms a strong bond with the walls of the cells and cements the cell together. As the fruit ripens, enzymes in the cells dissolve the pectin. When this happens the cells are no longer tightly bound to each other and the fruit becomes soft to the touch. Heating also dissolves the pectin. That is why vegetables and fruit become soft when cooked.

Rather than focusing on the ripeness of fruit to try and manipulate your diet into being healthier, consider the many other factors that can affect the quality and nutritive value of your food, such as whether a fruit is in season, or if it has been frozen. Some other factors to think about include the fruit’s time to market, as well as the temperature and humidity it has been exposed to during the shipping process. Eating ripe fruit is almost always more enjoyable, from a taste perspective, and it should have the same or a greater effect on your health as eating an under ripe fruit.

 

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Mountaineers find it time-consuming and difficult to brew a good cup of tea or cook food, especially as they climb higher. You just can’t make your usual cup that cheers on the top of Mount Everest.

Water normally starts boiling when it reaches a temperature of 100  (or 212 ). But this is true only if you are at sea level. As you go higher, due to a fall in the atmospheric pressure, water starts boiling at a lower temperature. (70  or 158  on the summit of Mount Everest!)

This heat is not enough to extract the best flavour from the tea leaves. Cooking in a saucepan or pressure cooker also takes much longer on mountain tops.

 

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In India currency notes are made up of pulp-containing cotton and balsam with special dyes to make the currency notes that should be resilient, durable, with quality to resist from wear and tear and not to be faked easily.

The materials used in the making of Indian currency notes have been starch paper blended with the textile fibers. While making currencies, these papers are instilled with gelatin to give strength to the currencies.

Chinese were the first to make currency notes and in ancient times Chinese currencies were made up of paper with mulberry bark and currently Japan has been using this fiber to make Japanese Yen currencies. Making of Indian currency notes is processed at Hoshangabad Security Paper Mill in Madhya Pradesh.

Banknotes also consist of a watermark and thread compromising of fluorescent, magnetic, metallic and micro print elements.

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Paper can be made from almost any kind of plant fibre. In some parts of the world, banana stalks and sugar-cane stems made fine, strong paper. On the whole, the longer fibres, the stronger paper. Paper money is folded, pushed into wallets and pocket, and passed from hand to hand. It needs to be very strong. A special paper is made that may contain cotton fiber (which come from cotton plants) or linen fiber (from flax plants).

Paper is made out of leaves and other plant fibers; you can find it in most art supply stores. Money is made with cotton fibers because they are stronger. The reason tress are used to make paper is that they provide the most fiber per square acre. There is not enough other fiber in the world to meet the demand for paper. Cotton was used for hundreds of years until the demand for paper was too much to keep up. Cotton rags were imported from other countries to try to keep up with demand until the 1800’s when somebody figured out how to get the fiber out of the trees by “digesting” them. The first paper we find in history was made from rice around 100 AD in China. Cigarette paper is still made with rice. All plants have cellulose fibers, leaves just don’t have as many fibers as wood.

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Paper was first made 2000 years ago in China. It was made from pulped rags and old fishing nets, drained on a sieve made of bamboo! Paper may not immediately seem to be an ideal building material, but it is light and cheap, and allows a certain amount of light to pass through it. It is ideal for use with bamboo, which is also very light. Paper has been used in China and Japan for centuries to make screens and internal sliding walls in houses. Although these are not soundproof, they are very attractive and easily replaced if damaged.

Paper making is one of the inventions by Chinese. 105 A.D. is often cited as the year in which papermaking was invented. In that year, historical records show that the invention of paper was reported to the Eastern Han Emperor Ho-di by Ts'ai Lun, an official of the Imperial Court. Recent archaeological investigations, however, place the actual invention of papermaking some 200 years earlier. Ts'ai Lun broke the bark of a mulberry tree into fibres and pounded them into a sheet. Later it was discovered that the quality of paper could be much improved with the addition of rags hemp and old fish nets to the pulp. The paper was soon widely used in China and spread to the rest of world through the Silk Road. An official history written some centuries later explained: In ancient times writing was generally on bamboo or on pieces of silk, which were then called it. But silk being expensive and bamboo heavy, these twoich materials were not convenient. Then Tsai Lun thought of using tree bark hemp, rags, and fish nets. In 105 he made a report to the emperor on the process of paper making, and received high praise for his ability. From this time paper has been in use everywhere and is called the "paper of Marquis Tsai."

In few years, the Chinese began to use paper for writing. Around 600 A.D. woodblock printing was invented and by 740 A.D., The first printed newspaper was seen in China.

To the east, papermaking moved to Korea, where production of paper began as early as the 6th century AD. Pulp was prepared from the fibers of hemp, rattan, mulberry, bamboo, rice straw, and seaweed. According to tradition, a Korean monk named Don-cho brought papermaking to Japan by sharing his knowledge at the Imperial Palace in approximately AD 610, sixty years after Buddhism was introduced in Japan.

Along the Silk Road, we learned that paper was introduced to Xinjiang area very early according to the archaeological records. The paper found at Kaochang, Loulan, Kusha, Kotan, and Dunhuang sites dated as early as the 2nd century. The technique eventually reached Tibet around 650 A.D. and then to India after 645 A.D. By the time Hsuan Tsang from China arrived to India in 671 A.D., paper was already widely used there.

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Cardboard is really just very thick paper. The machine that makes it is slightly different because the card is not wound onto a reel at the end, but cut up into sheets. For making strong, light boxes, corrugated cardboard is often used. This has paper pressed into a ridged shape sandwiched between two outer sheets.

We’ll discuss how strong cardboard boxes are, and why they are important for being able to carry anything.

The truth is, they seem disproportionally strong, and many are able to hold up to anything from 30 to 80 pounds, depending on both size, and quality, but if you get a double-walled cardboard box, you can minimally put about 60 pounds in there, up to 150 pounds in item weight. That’s huge!

How does this work? Cardboard is a single corrugated sheet, and a single wall one is made from kraft paper and glue, and three sheets are essentially stuck together with an adhesive of cornstarch, and then folded into the shape of a box, and from there assembled.  This might seem so simple, but it allows for a strong container.

So, how does it get the strength that it does? The secret is the construction of it, which is easier to understand when you equate it to normal construction processes.  You can imagine something being created? With pillars, beams, and the like, you’ll notice that those tend to be much smaller than the rest of the building, but they are capable of adding valuable and necessary support to a structure that would otherwise collapse.  Those small parts are what keep it together.

The corrugated parts of this are what help with strength, and the middle, in turn, acts as a type of support that allows for strength to be utilized to the outer sheets as well. Standard steel I beam, for example, is simple, but it has a design that allows for lots of support. The same is for cardboard.  The small corrugated areas are essentially tiny I-beams, and it works in the same way a bridge does, where it uses truss structure to bring more strength to both the interior and the exterior walls, so you’ll get double walled cardboard that’s much stronger than others.

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Nowadays most paper is made from specially grown trees. These trees are usually softwoods, grown in the cooler parts of the world where little else can thrive. Fir, pine, spruce, larch and cedar trees are all used. The trees do not have to be very tall or straight, as they do for timber. Almost all parts of the tree, except the bark, can be ground up into fibres for papermaking.

Most plant materials also contain nonfibrous elements or cells, and these also are found in pulp and paper. The nonfibrous cells are less desirable for papermaking than fibres but, mixed with fibre, are of value in filling in the sheet. It is probably true that paper of a sort can be produced from any natural plant. The requirements of paper quality and economic considerations, however, limit the sources of supply.

Pulped forest tree trunks (boles) are by far the predominant source of papermaking fibre. The bole of a tree consists essentially of fibres with a minimum of nonfibrous elements, such as pith and parenchyma cells.

Forests of the world contain a great number of species, which may be divided into two groups: coniferous trees, usually called softwoods, and deciduous trees, or hardwoods. Softwood cellulose fibres measure from about 2 to 4 millimetres (0.08 to 0.16 inch) in length, and hardwood fibres range from about 0.5 to 1.5 millimetres (0.02 to 0.06 inch). The greater length of softwood fibres contributes strength to paper; the shorter hardwood fibres fill in the sheet and give it opacity and a smooth surface.

Since cellulose fibre is a major constituent of the stems of plants, a vast number of plants represent potential sources of paper; many of these have been pulped experimentally. A rather substantial number of plant sources have been used commercially, at least on a small scale and at various times and places. Indeed, the use of cereal straws for paper predates the use of wood pulp and is widely practiced today throughout the world, although on a relatively small scale of production. Because many parts of the world are deficient in forests, the development of the paper industry in these areas appears to depend to a considerable degree upon the use of annual plants and agricultural fibres.

Nonwoody plant stems differ from wood in containing less total cellulose, less lignin, and more of other materials. This means that pulps of high cellulose content (high purity) are produced in relatively low yield, whereas pulps of high yield contain high proportions of other materials. Papers made from these pulps without admixture of other fibre tend to be dense and stiff, with low tear resistance and low opacity.

The morphology (form and structure) of the cells of annual plants also differs considerably from wood. Whereas the nonfibrous (parenchyma) cells of coniferous wood constitute a minor proportion of the wood substance, in annual plants this cell type is a major constituent. As hardwoods also often contain considerable amounts of nonfibrous cells, there is a closer resemblance between hardwood pulps and pulps from annual plants.

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A dandy roll has raised patterns on it. As it presses onto the wet paper at the end of the wire, it leaves impressions called watermarks. If you hold a piece of paper up to the light, you may see a pattern or wording left by a dandy roll.

A wire-covered cylinder located toward the end of the forming section of a papermaking machine that is used to squeeze excess water out of the wet paper furnish and even out the formation of the paper web. Raised designs woven into the dandy roll wire are used to add wove finish or laid finish texture to the paper, as well as a watermark.

The dandy roll was invented in 1826 in England by John Marshall, a maker of molds for watermarking handmade paper. After the invention of the papermaking machine (Fourdrinier brother), he developed the dandy roll technique as a means of watermarking machine-made paper. (Watermarks, Laid Finish, and Wove Finish.)

The dandy roll improves quality on Fourdrinier wire machines up to 1,000 m/min. The key feature is the patented self-supporting honeycomb with a large open surface. The honeycomb is easy to clean and prevents undesirable ring marks in the paper due to its special design. The dandy roll works by being immersed into the free suspension and lightly wrapped by the wire. By unwinding the dandy roll wire on the top side of the web, the latter is smoothed. The intake pressure causes the stock water to penetrate the dandy roll fabric into the interior of the dandy roll. The flow is thus oriented in such a way that freely floating fibers in the suspension reach the fabric and are deflocculated there. The combined steam-water spray tube, the simple adjusting unit, quick retraction and heated chamfers are some of the other tried and tested features of the well-engineered dandy roll device.

Water that is centrifuged out of the dandy roll into the outlet is securely caught with a drop collection device, which can easily be retrofitted onto the dandy rolls of other manufacturers.

Paper is a dried, compressed mat of plant fibers—nothing more, nothing less. It's a bit like clothing you can write on. No, really! Clothes are made by weaving together yarns such as cotton and wool spun from natural fibers. Paper is more like the fabric we call felt, made without the weaving stage by pressing together cellulose fibers extracted from plants and trees so they knit and fuse to form a strong, solid, but still very flexible mat.

Most paper pulp is made from trees (mainly fast-growing, evergreen conifers), though it can also be made from bamboo, cotton, hemp, jute, and a wide range of other plant materials. Smooth papers used for magazines or packaging often have materials such as china clay added so they print with a more colorful, glossy finish.

Here's the basic idea: you take a plant, bash it about to release the fibers, and mix it with water to get a soggy suspension of fibers called pulp (or stock). Then spread the pulp out on a wire mesh so the fibers knit and bond together, squeeze the water away, dry out your pulp, and what you've got is paper! Paper is really easy to make by hand (try it for yourself) but people use so much of it that most is now made by giant machines. Whichever method is used, there are essentially two stages: getting the pulp ready and then forming it and drying it into finished sheets or rolls.

Papermaking by hand

The raw plant material is placed in a large vessel filled with water and literally beaten to a pulp to make a thick suspension of fibers called half-stuff. This is formed into sheets of paper using a very basic frame made of two parts: a metal mesh called a mold that sits inside a wooden frame known as a deckle (a bit like a picture frame). The mold and deckle are dipped into the half stuff and gently agitated so an even coating forms on top, with most of the water (and some of the pulp) draining through. The deckle is then removed from the mold and the soggy mat of paper is placed on a sheet of felt. This process is repeated to make a number of interleaved sheets of paper and felt, which are then placed inside a screw-operated press and squeezed under immense pressure to squash out virtually all the remaining water. After that, the sheets of paper are taken out and hung up to dry.

Papermaking by machine

Although some expensive papers are still crafted by hand, most are churned out quickly, efficiently, and automatically by gigantic machines. Pulp is prepared for papermaking machines either mechanically or chemically. The mechanical method (generally used to make lower-grades of paper) is called the ground-wood process, because the pulp was originally made by using huge stones to grind up logs. Nowadays, pulp is prepared by giant machines that cut, wash, chop, beat, and blend wood, rags, or other raw materials into a soggy mass of fibers. In the chemical method, known as the Kraft process (from the German word for "strength," because it produces strong paper), plant materials are boiled up in strong alkalis such as sodium sulfide or sodium hydroxide to produce fibers. At this point, loading materials (surface coatings such as clays), dyes (to make colored paper), and sizes (to strengthen and waterproof and prevent inks from spreading) can be added to the mixture to change the properties of the finished paper (sometimes they're added later).

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