SCIENCE TRIBUNE Thursday, February 6, 2003, Chandigarh, India

Electronic paper a reality
K.K. Jayanthi
ne of the fundamental drawbacks of conventional paper is that it cannot be reused once it has been written upon. Now imagine what can be done with paper that can be written upon, the writing erased instantaneously and again written upon, millions of times without wearing out.

Marconi’s radio is 100
Dave Haskell
t is interesting to speculate what Gugliemo Marconi would think about the state of radio communications today. Doubtless the "Father of Radio" would be amazed at cellular telephones and space communications, but perhaps feel some satisfaction for having helped spark a technological revolution.

Rain falls in drops. Why does it not flow down like a river?




Electronic paper a reality
K.K. Jayanthi

Produced in a roll, like old-fashioned paper, SmartPaper is actually two sheets of thin plastic with millions of tiny bichromal beads embedded in between. 

One of the fundamental drawbacks of conventional paper is that it cannot be reused once it has been written upon. Now imagine what can be done with paper that can be written upon, the writing erased instantaneously and again written upon, millions of times without wearing out.

The technical concept of electronic reusable paper was first mooted 30 years ago by Nicholas K. Sheridan, a researcher at Xerox’s Palo Alto Research Centre. He came up with the basic idea of a display medium comprising very tiny plastic beads embedded in a flexible transparent film.

Each bead is two-toned: one half white and one half black, with an opposing electrical charge on each half. Apply an appropriate electric field to the transparent surface, and a bead can be rotated to lock either a white or black dot onto the viewing plane-creating, in effect, ink that twists itself into the right place. Sheridon called his invention Gyricon, Greek for "rotating image."

With the commissioning of the $ 10 million, 48,000 sq ft manufacturing facility of Gyricon Media Inc at Ann Arbor (Michigan) in August, 2002, the commercial availability of electronic paper, is a reality.

Gyricon has branded its product as SmartPaper.

Each bead is smaller than a grain of sand and has a different colour on each half or “side ”. The hemispheres are also charged differently (i.e. positive or negative).

The Gyricon technology uses an array of tiny (100 micron diameter or smaller) solid beads with one hemisphere of each bead one colour (e.g. white) and the other a different colour (e.g. black). these beads are embedded in a flexible plastic sheet in small cavities surrounded by a liquid. Each bead carries an electrical charge. When an external electric field is applied the bead rotates.

Adhesive forces between each bead and cavity wall require an electrical threshold be exceeded before it will rotate. This makes an image electrically "printed" onto the material stable and unchanging until "erased" by another transmission. Electrical signals can be applied to the SmartPaper sheets through fixed surface electrodes or a moving stylus.

Applying electrical fields to the display surface changes the image on SmartPaper. A range of techniques (with different flexibility and cost factors) will achieve this result. In the least expensive option, the back plane contains several possible images or preprogrammed text and digit messages (this is called a Multiple Fixed Image or MFI sign). Alternatively, the back plane can contain circuitry addressed to an array of pixels that can be written individually.

Which image or message is displayed can be controlled by either programming the sign to display a fixed sequence when it is manufactured or a dynamically changeable sequence using special software and a wireless network attached to a local PC or the Internet.

Due to the way SmartPaper signs are constructed, they cannot be tampered with by magnets, static electricity, PADAS, cell phones, or other electronic devices. Apart from ensuring that batteries have sufficient charge, signs made with SmartPaper can be easily cleaned by wiping with a damp cloth or normal non-abrasive window cleaners. It does not use or contain any toxic chemicals or other hazardous materials nor does it require any special handling or disposal.

A networked programmable sign using SmartPaper will run for up to 2 years on 3 AA batteries, with the power almost completely used by the communications and processing systems. SmartPaper itself requires just a capacitance or voltage (about 100 volts), not a power current.

Unlike other types of electronic displays (LED/LCD), SmartPaper has a wide viewing angle identical to traditional printed signs. This allows it to be viewed like paper, from all angles and without added backlighting. Images do not "wash-out" in fluorescent or bright lighting.

Displays made with SmartPaper generally do not degrade over time and will last for years because the images are based on pigments rather than dyes. Signs made with SmartPaper have performed more than 5 million image changes without malfunction or fading. Images displayed on SmartPaper are "held" indefinitely until a new electrical signal is applied.

SmartPaper is fundamentally suitable to both indoor and outdoor display uses. However, displays will offer optimal performance in indoor applications with ambient temperatures from 0.50 C.

Gyricon Media, Inc. currently plans to use the technology to develop applications for signage and point-of-purchase displays found in supermarkets, department stores and other retail outlets. Current models of signage made with SmartPaper are 3/4" thick including the housing. Unhoused sheets of SmartPaper can be made to less than 1/10" thickness.

Smaller-size beads necessary for higher resolution are on the way. As for a full range of colors, Sheridon has been issued a patent for subtractive color using transparent Gyricon beads with thin disks of color filter material in cyan, magenta and yellow, each addressable by different voltage levels.

SmartPaper technology is obviously well suited to a wide variety of other market applications, including PDA displays and electronic books/newspapers. Sheridon has predicted that the pliable, reusable e-newspaper or e-magazine of the future "could happen in a few years."

He happens to have a concept model: a slit aluminum cylinder from which he pulls out a sheet of SmartPaper, papyrus scroll-like. In a working model, an array of electrodes along the edge of the cylinder would imprint up-to-the-minute news or feature stories on the paper’s flexible, rubbery surface; plastic sheets would protect the paper from being damaged.

Nevertheless, as paperlike as it may become, this electronic paper may never feel exactly like the original. Sheridon admits. "It will never be as light as paper, Paper is about four mils thick; this will always be 12 or 15 mils thick. But it doesn’t have to exactly replicate paper to be useful."


Marconi’s radio is 100
Dave Haskell

It is interesting to speculate what Gugliemo Marconi would think about the state of radio communications today.

Doubtless the "Father of Radio" would be amazed at cellular telephones and space communications, but perhaps feel some satisfaction for having helped spark a technological revolution.

The first wireless transmission between the United States and Europe took place on January 18, 1903.

The first message in the historic 1903 telegram, in Morse code, was from President Theodore Roosevelt to Britain’s King Edward VII. Roosevelt was sending his "good wishes" to the king and his people, and celebrating the "wonderful triumph of scientific research and ingenuity which has been achieved in perfecting a system of wireless telegraphy."

A short wait later, the king, from a transmission station in England replied, thanking Roosevelt for his "kind message".

Marconi, who lived from 1874 to 1937, was awarded the Nobel Prize in physics in 1909.

There’s little left of Marconi’s original transmission facility on Cape Cod, Mass.

When the Roosevelt-king telegram was sent, the site had a transmission house and four wooden towers rising 210 feet above the sand, supporting a giant antenna of several hundred copper wires. Much of the original site has been eroded by the sea. Visitors can see what’s left of the transmitter house and on the encroaching beach, at low tide, the base of one tower.

Marconi, who was born in Bologna, Italy, began experimenting with radio waves in the early 1890s, and over the following years laid the foundation for what today is known as radio.

He successfully made wireless transmission over short distances across the English Channel and to ships at sea, but the prevailing theory at the time was that radio waves could not be sent much more than 200 miles because of the curvature of the Earth.

Marconi, building sites on both sides of Atlantic, set out to prove otherwise.

In 1901, he used his system to transmit the first wireless signal — there Morse code dots for the letter "S" — across the Atlantic from the British station at Poldhu, Cornwall, to an antenna hoisted as high as possible on balloons at St. John’s Newfoundland.

The experiment proved that radio waves would not be lost because of the curve of the earth.

He later wrote, prophetically: "I now felt for the first time absolutely certain that the day would come when mankind would be able to send message without wires not only across the Atlantic but between the farthermost ends of the earth."

Building on that success, Marconi established a larger facility with the four towers at South Wellfleet, making history in 1903 with the first trans-Atlantic radio exchange.

As countless millions of people around the world walk around with their cell phones today, little thought is given to that moment in history 100 years ago. UPI



Rain falls in drops. Why does it not flow down like a river?

A. This is a beautiful question. I am sure you would agree that it would be a bit unpleasant if a river were to descend on us unexpectedly in the middle of the night as rain often does.

As you know, rain is made up of moisture that is evaporated from large bodies of water. The amount of water vapour in the atmosphere increases when the water bodies are hot. Moisture laden air moves towards land when it becomes hotter than the sea. When this air rises, say by going over a mountain, it cools. Cool air cannot hold as much vapour as hot air. Therefore the vapour condenses into clouds. Clouds are made up of tiny drops of water suspended in the air. An upward motion of the clouds cools them and the tiny droplets join each other to become bigger.

Sometimes these droplets freeze into tiny crystals of ice. Large drops and ice crystals become too heavy to float around in the atmosphere. They start descending. In our part of the world the ice crystals melt and the water droplets get bigger while coming down. But they come down only as drops and not torrents of water as if a tap had been opened. Various parts of the cloud do not act in unison while rising up to colder regions. No air mass is capable of suddenly removing all the heat from the vapour in the atmosphere to turn it into a lake of liquid water that might fall or flow onto the earth as a river.

Incidentally, even if there were a large tank of water very high in the atmosphere and a tap was used to bring a stream down to the earth the result would be a thick shower and not a steady connected stream. Just try it by opening the tap of a water jug held over the ledge of a roof. Here I will not go into the explanation for breaking up of the stream while descending.

The fact that cool air cannot hold as much moisture as hot air is easily proved by a simple experiment. Put some ice in a metal glass and leave it on the table. After some time you would notice that the glass is wet on the outside. This is due to the moisture that warm air has shed on being cooled by touching the cold glass.

When water is boiled it changes into oxygen and hydrogen. But if we hold a burning stick above the steam the same oxygen and hydrogen, instead of instigating fire, extinguish the burning stick. Why?

We cannot produce oxygen and hydrogen just by boiling water. Steam is just a gaseous form of water. The process of boiling does not provide enough energy to break the bond between hydrogen and oxygen atoms in a water molecule. We can, on the other hand, produce hydrogen and oxygen by passing an electric current through water. This is called the process of electrolysis.





1. Plants that soak arsenic out

of water and still flourish.

4. A hydrated oxide of iron.

6. Physical or chemical inter-action of two or more substances.

8. A dangerous disease that spreads on removal of swellings caused by it.

10. Minimum distance at which reception of sky wave is possible.

12. Abbr. judging the knowledge of a person (like IQ).

13. Abbr. for a diesel engine on ground supplying energy to other romp equipments.

16. A unit for expressing ratio of two values.

17. A mixture of sulphides of iron and copper obtained in smelting of copper.

19. A star that ejects a small part of its material in the form of a gas cloud.

22. Perforated plug or metal lining of orifice.

23. A plumbing special.

24. Abbr. for a semi-automatic self loading rifle.

25. Units of loudness.

26. Angle between 180 to 360 degrees.

27. Abbr. for an analyzer which is based on ISDN measurements.


Down :

1. Any part of a solid figure cut by a plane parallel to its base.

2. A number forming the base of a system of numbers is called so.

3. Abbr. for a Satellite test centre.

4. A unit of ionizing radiation such as X-rays.

5. Prefix for one million million.

7. Abbr. for Indol-3-ethanoic acid.

9. A system of electromagnetic units.

11. Units of capacity.

14. A stable elementary particle having electrical charge.

15. A central conducting wire together with a concentric cylindrical conductor.

18. Covering of natural or artificial grass.

20. An opening that serves as an outlet for air.

21. Abbr. for a term used in spectroscopy.

24. Symbol for Strontium.

Solution to last week’s


After a run of more than one year, we are bringing the Crossword column to a close. The warm response of the readers assures us that it has helped them in brushing up their knowledge of science-related matters. — Editor