Category Science

What is the revolution of the fibre optics?

Telephone cables carrying messages at the speed of light have given a new lease of life to telecommunications. The amount of information now transmitted – telex, fax and computer data as well as telephone calls – was straining the copper-cable system to the limit. Fibre optic cables, with thir high capacity, small size and freedom from electrical interference, are the key to development.

The first uses of optical fibres was in medicine in 1955, for lightning up parts of the inside of the body. The light loss through the fibres was at first too great for many other uses. But in 1966, Dr Charles Kao and Dr George Hockham, two scientists working in Britain at the Standard Telecommunications Laboratories, discovered that the loss was due to impurities in the glass. By 1970, due to impurities in the glass, Corning Glass, had produced fibre optics good enough to transmit telephone signals.

Fibre-optic cables are now gradually replacing copper ones between exchanges. The first transatlantic fibre optic cable, TAT-8 – jointly laid by American, French and British companies – began service in 1988, its capacity of around 40,000 simultaneous telephone calls is three times as great as the seven existing copper transatlantic cables put together.

 

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Starting seeds and rooting cuttings

  • Make seed holes with chopsticks

Instead of buying a dibber — the wooden garden tool used to poke seed holes in the soil — use a chopstick or pencil instead. You’ll get the same holes for free. Another choice is a full-sized pair of folding nail clippers, the blunt arm of which you can poke into the soil and twist. When the time comes to transplant seedlings, use the same arm of the clippers to work a seedling and its rootball from the soil.

  • No dibbing (or watering) required

An alternative to dibbing holes into the soil of a seed tray is to wet the soil, lay the seeds on the surface then cover them with another thin layer of soil. Cover the tray with a tight layer of plastic wrap and your job is done. Condensation on the wrap will drip down to keep the seeds moist until germination.

  •  Spice jars as seed sowers

Before sowing seeds directly into a seedbed, put them in an empty dried herb or spice jar — the kind with a perforated plastic top. Then shake the seeds out over the seedbed or along a row.

  • Sowing tiny seeds

Seeds of impatiens, lobelia, carrots, lettuce and a few other flowers and vegetables are so miniscule that they are difficult to sow evenly. To remedy the problem and make seedlings easier to thin out once they sprout, combine the seeds with fine dry sand and add the mix to an empty salt shaker. This will put some space between tiny seeds.

  •  Make your own plant markers

To label your seeds tray by tray so you won’t risk confusing your specially chosen tomato varieties, turn empty yogurt pots, cottage-cheese tubs or other white plastic containers into plant markers. Cut strips from the plastic, trim the ends to a point and use an indelible felt-tip marker to write the plant name (variety included) on each. Stick the strips into the edge of the trays as soon as you plant seeds so you’ll know which plant is which from the start.

  •  Paper-cup seed starters

Small paper drinking cups make excellent seed starters. They’re the right size, you can easily poke a drainage hole in the bottom and they’re easily cut apart when it comes time to plant your seedlings. Note that we specify paper cups: polystyrene cups may sit in landfill until your great-great-grandchildren have come and gone.

  • Dry-cleaning bag humidifier

To provide the humidity needed to root a tray of cuttings, lay a dry-cleaning bag over the cuttings, making sure that it doesn’t touch the plants. (Paddle-pop sticks or pencils can serve as ‘tent poles’.) Clip the bag to the rim of the seed tray with clothes pegs or small bulldog clips.

  •  Root rose cuttings under glass

An easy way to root a cutting from your favourite rosebush is to snip off a 10-15-cm piece of a stem that has flowered and plant it in good soil in a pot. Then cover it with a large glass jar to create a mini-greenhouse.

  • Willow-tea rooting preparation

Soak a handful of chopstick-sized fresh willow twigs in water to make a solution of natural plant-rooting hormone tea. Cut 6-8 twigs from a willow (any species), then split them. Cut twigs into 7-cm pieces and steep them in a bucket filled with 9-12cm water for 24 hours. Use the tea either to water just-planted cuttings or as an overnight soaker for the base of cuttings.

  •  A rolling seed tray

Recycle an abandoned, old toy cart into a seed tray on wheels. Poke holes in the cart bottom with a screw-hole punch and hammer, then fill the cart with coconut fibre peat pots or expandable peat pellets, labelling as you go.

  •  Potatoes as transporters

When moving plant cuttings to another location, you can use a potato as a carrier. Simply slice a large potato in half crossways, poke three 2cm-deep holes in each cut side with a chopstick or pencil, then insert the cuttings, which should stay moist for about 3-4 hours.

Credit: Reader’s Digest

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WHY DO COMPANIES ADVERTISE?

Companies use all forms of media to advertise their products and services. advertising began simply as a way of telling people about a product, but it is now much more sophisticated. It is used to present the image of a company in a certain way and also to target a particular audience that the company feels it can attract. In this way, the company associates itself with a certain lifestyle. Advertising is a huge business, with large companies investing huge sums of money in anything from sports sponsorship to putting their logo on the side of a milk carton.

Companies use advertisements as part of a marketing program to increase sales of their products and services. Advertising plays a different role at different stages of the marketing process — helping to raise awareness of a product or service, generating leads for a sales force or selling directly. Companies with retail outlets use advertising to make consumers aware of product availability and increase sales through the outlets.

Awareness

Companies use advertising to make customers and prospects aware of the features and benefits of their products. If customers are not aware of your product, they will not consider it when they next make a purchasing decision for the type of product you offer. Advertising puts your product into the consumer’s set of choices.

Brand Preference

Advertising can build a preference for your product over competitors’ offerings. Your advertising messages must reflect the information that customers feel is important when choosing a product. It must also stress the quality of your product. By advertising regularly, you can reinforce the brand messages so that your product becomes first choice when the consumer next makes a purchase.

Direct Sales

Use direct response advertising to sell products directly to customers. The advertisement includes details of the product and its price together with a telephone number or website address where customers can order the product.

Retail Development

Advertising details of retailers or distributors that stock your products builds sales by driving traffic to the outlets. The advertisements can provide information on retail outlets or promote special offers available at those outlets. This type of advertising can also help you promote your products to distributors and retailers.

Lead Generation

If you market products and services through a sales force, you can use advertisements to generate leads for the team to follow up. Include a response mechanism in the advertisement such as a reply coupon, telephone number or email address so that customers can register their details in return for an incentive offer. Examples of incentives include free copies of special reports for business customers or gifts for consumers.

Reputation

When a prospect is selecting a supplier for a major purchase, company reputation is an important factor in the decision. Use advertising to build a positive perception of your company. Reputation or corporate advertising communicates messages about factors such as your company’s achievements, financial stability, market success and innovation record.

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WHAT IS MASS MEDIA?

Certain forms of media, particularly television and newspapers, are able to communicate to thousands or even millions of people at the same time. These mass media can have a very powerful influence on their audience, and often reflect the particular view-point of the media-owner.

Think about this for a second: whenever you want to hear your favorite song, watch your favorite show, or see the latest current events, where do you go? You more than likely turn on your television, radio, or computer. The source that the majority of the general public uses to get their news and information from is considered mass media.

Mass media means technology that is intended to reach a mass audience. It is the primary means of communication used to reach the vast majority of the general public. The most common platforms for mass media are newspapers, magazines, radio, television, and the Internet. The general public typically relies on the mass media to provide information regarding political issues, social issues, entertainment, and news in pop culture.

The mass media has evolved significantly over time. Have you ever wondered how the latest news and information was communicated in the past? Well, before there was the Internet, television, or the radio, there was the newspaper. The newspaper was the original platform for mass media. For a long period of time, the public relied on writers and journalists for the local newspapers to provide them with the latest news in current events.

Centuries later, in the 1890s, came the invention of the radio. The radio would soon supersede the newspaper as the most pertinent source for mass media. Families would gather around the radio and listen to their favorite radio station programs to hear the latest news regarding politics, social issues, and entertainment.

Later on down the line came the invention of the television. The television would soon replace the radio for the most effective platform to reach the general public. Today, the Internet is the most relevant form of mass media and has become a major tool for news outlets. Since the evolution of the Internet, the general public is now able to access those same news outlets in an instant with just a click of a mouse, instead of having to wait for scheduled programs.

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HOW IS INFORMATION SENT AROUND THE WORLD?

In the modem world, we can access information in ways that could only be dreamt about just 50 years ago. Information can travel around the world via television, radio, telephone and computer networks, all of them connected by satellite or cable links. Modern communication systems, or media, allow almost anyone to transmit and receive verbal, visual and written information wherever they are in the world.

Optical communications networks provide the underlying high-capacity, ubiquitous connectivity that underpins the global Internet Characterizes the growth of communication and computing between 1986 and 2007, based on a broad collection of data. Around the year 2000, Internet traffic took over from voice telephone as the single largest communication format for information. Now Internet traffic dominates completely. All of the long-distance communications on the Internet are over optical fiber.

Major advances in transmission techniques and technologies have allowed network providers to provide extremely cost-effective network upgrades that have kept pace with the extraordinary appetite for broadband Internet services. That growth, as exemplified in has driven network bandwidth demands by a factor of 100 over the last 10 years. That increase has been enabled by realizing the full potential of wavelength division multiplexing (WDM) that has resulted in fibers carrying as many as 100 separate wavelengths. In addition, the capacity per wavelength in commercially deployed terrestrial networks has increased from a maximum of 10 gigabits per second (Gb/s) per wavelength when the first edition of Harnessing Light was published in 1998, to 100 Gb/s today. As a result, per fiber transmission capacities in terrestrial systems today as high as 5-10 terabits per second (Tb/s) are possible. Transoceanic capacities have lagged somewhat behind terrestrial values because the long amplifier-only distances and the desire to extend the amplifier spacing have made upgrading to per wavelength capacities above 10 Gb/s problematic. Nevertheless, transoceanic per fiber capacities of approximately 1 Tb/s are typical. For the future there are expectations that this growth will continue as more video content calls for bandwidth and that there is a need for another factor-of-100 growth in the coming 10 years as well.

Major advances have also been achieved in both cost-effectively managing the large capacity in today’s WDM optical networks and in leveraging the value proposition of optical amplifiers to provide multi-wavelength amplification over network mesh and ring architectures. Reconfigurable, wavelength-routed networks—in which wavelength-defined units of capacity can be added, dropped, or switched from one fiber route to another fiber route directly in the optical domain without the need for conversion to electronics—are now heavily deployed in long-haul terrestrial networks as well as metropolitan networks. Wavelength-routed networks provide cost-effective solutions because they allow data on wavelengths passing through a node at a multi-route network node to remain in the optical domain and benefit from the cost-effective multi-wavelength amplification enabled by optical amplifiers, rather than needing to be individually electronically regenerated. The large increase in capacity demand has ensured that a prerequisite for the economic viability of such networks—namely, that the capacity demand between any two node pairs on the network be at least as large as that which can be carried by a single wavelength—is met.

WDM optical networks require reconfigurable optical add/drop multiplexers (ROADMs) to, under network electrical control, drop or add wavelength channels at a node and to switch wavelength channels from one fiber route to another. ROADMs are key enablers that have evolved significantly in their functionality, providing increasing levels of flexibility, and in their capacity, or number of fiber ports and wavelengths per fiber, over the last decade. Further progress in these network elements and their enabling technologies will be essential to addressing the growing demand for capacity.

Ultimately, networks are no better than the access capacity that they provide to the end user, whether that customer is a business or a residence. Increasingly that access is through an optical link. The last decade has seen significant increase in the deployment of fiber in the access network, initially to the curb, but increasingly also directly to the business or home.

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How wavelength is measured?

All electromagnetic waves travel at the speed of light – about 186000 miles (300,000km) per second. They are called electromagnetic because they consist of both electric and magnetic fields acting at right angles to each other. The fields leapfrog each other, giving the wave its motion like the snaking of a length of rope when it is jerked.

The height of a loop half the distance between the customer and the trough is called the amplitude. Waves can also be measured by their frequency, that is, the number passing a given point each second. The longer the wavelength, the lower the frequency.

Frequencies are measured in units called hertz, named after the German, Heinrich Hertz, who in 1888 demonstrated that electric signals could be sent through the air.

He passed a high-voltage current through a loop of wire that had a metal sphere at each end, causing a spark to jump the short space between them. At the same time, another spark jumped between the spheres of a separate, similar wire loop placed on the other side of the room.

Hertz proved that the energy transmitted from one loop to another was electromagnetic radiation, which had been predicted theoretically by a British scientist, James clerk Maxwell, in 1864.

The hertz measurement of a frequency gives a number of complete waves, or cycles, per second. Frequencies are usually expressed as kilo hertz (thousands of hertz), megahertz (millions of hertz) or gigahertz (thousand millions of hertz). Light waves are extremely short. The longest, the red, measure about 36,000 to an inch (14,000 to a centimetre) and have a frequency of around 100,000,000 MHz. Radio waves used for communication, however, range in length from about 1/25 of an inch of (1 mm) to about 18 to 20 miles (30 km), and have frequencies ranging from 10,000 Hz to about 30,000 MHz.

 

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