SCIENCE TRIBUNE Thursday, November 29, 2001, Chandigarh, India
 

What the stars are made up of
Balraj Singh
F
OR many years, it was thought that in order to know the chemical composition of stars, it was necessary to bring them down to earth in real sense of the word — ie, some method should be devised to bring samples from them. Given their distance and temperature, scientists believed that we would never be able to know their composition. But the innovative human mind solved this problem through the discovery of atomic spectra German scientists Kirchhoff and Bunsen discovered that each chemical element has its own characteristic spectrum.

Beware of toxic substances
Shyamal Koley
W
E are living in the era of science and technology. Knowing or unknowing we do use chemical products, which are toxic, in our everyday life. In morning, we use toothpaste which contains flouride. Consumption of more than 2 ppm fluoride per day is harmful for health. Excess intake of fluoride may cause dental carries, back pain, bent limbs and many other health problems.

Automated sign verification
Deepak Bagai
P
ATTERN recognition is the branch of computer science in which the automatic detection of objects takes place. Automated identification of handwriting and signature verification is one of the numerous application domains of pattern recognition. With the emergence of electronic commerce, the research in the field of signature verification has gained paramount importance.

High-security registration plates
Raj Kumar Aggarwal
T
HE Government of India has mandated that a new system of high security registration plate shall be used on all new vehicles, for vehicles already in use, this order shall come in to force two years from the date of publication of this order in the official gazette.

NEW PRODUCTS & DISCOVERIES
Never set your watch again
T
HE world has become a smaller place in the past few decades. Transactions take place across the world in an instant. Having a timepiece that can not only keep perfectly accurate time, but keep track of the time zones can be really helpful and convenient. Now there is a watch that scientifically gives the right time in all zones.

  • Light pollution increasing
  • Pandas with high BP

SCIENCE QUIZ
J. P. Garg tests your IQ

   
 
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What the stars are made up of
Balraj Singh

FOR many years, it was thought that in order to know the chemical composition of stars, it was necessary to bring them down to earth in real sense of the word — ie, some method should be devised to bring samples from them. Given their distance and temperature, scientists believed that we would never be able to know their composition. But the innovative human mind solved this problem through the discovery of atomic spectra German scientists Kirchhoff and Bunsen discovered that each chemical element has its own characteristic spectrum. This is because atoms absorb energy by transferring their electrons to “excited states” and as these electrons jump back to their ground state, they emit radiation, characteristic of the element to which that atom belongs. This fact can be analysed at home by sprinkings a pinch of common salt on a candle. The resulting yellow glow is characteristic of sodium, which is present in the salt. So, the spectrum of a star contains fingerprints of all the elements of all the elements present in its surface layers.

In 1911, Danish astronomer Ejnar, Hertzspring compared the colour and luminosity of stars from several open clusters. As all stars in a particular cluster are practically at the same distance from us, their observed brightness (apparent magnitudes) represents a direct measure of their absolute brightness (absolute magnitudes). He found that instead of being randomly scattered, the points on the colour-luminosity chart were clustered in well-defined regions and curves. In 1913, an American astronomer named Henry Russel reached the same conclusion for a different seat of stars. This brightness colour graph is popularly known as “Hertzsprung- Russel Diagram” or simply the HR diagram.

While we cannot observe the complete evolution. HR diagram helps us correlate and understand the complex processes occurring over periods of millions of years. The stellar spectra are grouped into seven principal classes, viz. O, B, A, F, G, K and M in decreasing order of temperature. Thus, O type stars are bluish, while M are reddish in colour. These classes are further subdivided as A0, A1,...A9, F0, F1 etc. to account for minor variations. Our sun is a G2 type star.

Massive stars occupy upper-left positions, while small ones populate the lower-right region of the diagram. Depending upon their mass, all stars trace their own paths on the HR diagram in their lifetime. However in their lifetime. However , all of them stay in the main sequence for the major part of their life. A star enters the main sequence phase as the gravitational contraction in the protostar initiates the fusion of hydrogen into helium. The heat thus generated halts its further gravitational collapse and the star attains a state of equilibrium. As fusion requires a very high temperature, pressure and density, it can occur only in the central regions of a star. For example, only 12 per cent mass of our sun is involved in the fusion reaction. The outer shell of the star, where temperature and pressure are comparatively less, contains the remaining unburnt hydrogen gas.

A star leaves the main sequence after the hydrogen in its core gets exhausted. In the absence of a heat source, the star begins to collapse under the influence of gravitational force. The amount of heat generated enough heat and pressure to initiate fusion of helium, a small (less than half our sun) one will end its life at this stage as a white dwarf.
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Beware of toxic substances
Shyamal Koley

WE are living in the era of science and technology. Knowing or unknowing we do use chemical products, which are toxic, in our everyday life. In morning, we use toothpaste which contains flouride. Consumption of more than 2 ppm fluoride per day is harmful for health. Excess intake of fluoride may cause dental carries, back pain, bent limbs and many other health problems.

In kitchen, bathroom, bedroom, drawing room and in study room, even in our work places, quite frequently, we use various chemical substances which are harmful enough. In bathroom, with the use of aerosol sprays, trichoroethane may come in contact with our body causing dizziness and irregular breathing. In winter, often we take bath in water of hot showers which is chlorine-treated. The result is that, chloroform is formed and may get in touch with our body causing possible threat of cancer.

Cancer may also invade our body through para-dichlorobenzene comes from the sources of air freshners and mothball crystals. In bedroom, dry-cleaning fluid fumes on clothes sometimes form tetracholoroethylene causing nerve disorders, damage to liver and kidneys, even bears a possible threat of cancer. In our drawing room, from furniture stuffing, paneling particle board and foam insulation, formaldehyde may come in contact with our body causing irritation of eyes, throat, slin and lungs, nausea and dizziness. Possible threat of lung cancer is therefore benzo-a-pyrene which comes from the sources of tobacco smoke and wood stoves. A chemical called styrene comes from carpets and plastic products may come in contact with our body which may cause kidney and liver damage.

Tobacco smoke may come from cigarette causing lung cancer, respiratory ailments and heart diseases. Radon-222 is a chemical that generally comes from radioactive soil and rock surrounding foundation and water supply which may also cause lung cancer.

From paint strippers and thinners, methylene chloride may get in touch with our body causing nerve disorders, also diabetes. Carbon-monoxide and nitrogen oxides come from the sources of faulty furnaces, unvented gas stoves and kerosene heaters, wood stoves, causing headache, drowsiness, irregular heartbeat, irritated lungs and children’s colds. Asbestos comes in contact with our body by pipe insulation, vinyl ceiling and floor tiles which may cause lung disease and lung cancer.

In most villages of our country, villagers use aluminium containers for cooking food. National Institute of Nutrition (NIN), Hyderabad, undertook a study to assess the aluminium content of commonly consumed Indian foods. They reported that usage of aluminium utensils contributed significantly to the total daily intake of aluminium. Leaching of aluminium from the vessels into food occurs greatly when they are used for preparing acidic foods, such as tamarind containing leafy vegetables or tomato-containing dal. Moreover, such leaching increases in new aluminium vessels. It is also reported that calcium and iron deficiencies enhance aluminium absorption. In fact, iron deficiency is suboptimal in most of the Indian population, especially in children, pregnant and lactating women. These groups are at risk due to aluminium absorption. Aluminium is used in certain antacids, anti-diarrhoeals and analgesics. Aluminium toxicity may cause learning disabilities in children. Several disorders of nervous system, such as dialysis dementia, senile dementia and Parkinson’s dementia, may have some close association with increased ingestion of aluminium.

Canned foods generally are sealed with lead wrappers. Lead contamination of food is posing a very serious threat to health. Excess lead has many harmful effects i.e. of appetite, vomiting, nausea dizziness and mental retardation. Concentration of lead in food has been increased also due to pollution from industry and automobiles. Often we inhale organic lead emitted from automobiles. These easily get absorbed in brain, kidney, liver and blood. As a consequence, brain damage, muscle paralysis, convulsions may occur or even death.

A recent report shows that arsenic poisoning through contaminated water has become a public health problem over six districts of West Bengal affecting more than one million people. WHO prescribes the safe level of arsenic is 0.05mg./litre in human body. When the arsenic concentration in our body rises over his safe level, it is deposited in human body causing sores on hands and feet, loss of appetite, disclosed pigmentation on skin. It can induce peripheral neuritis resulting in motor and sensory paralysis of the limbs. Arsenic can cause cirrhosis of the liver, cancer of skin and cancer of the liver.

We should be well aware about the ill-effects of pesticides and insecticides which we use frequently in agricultural fields. All pesticides and insecticides are toxic in nature. While spraying these substances in agricultural fields, gradual inhalation of these toxic substances may cause carcinogenesis. Paul Muller once was conferred with the Nobel Prize for the invention of DDT, but it has become a dreadful boomerang now. Insects have become immunised, humans are getting infected.

We usually consider fruits and vegetables free from contamination. The notion often becomes untrue. All the leafy vegetables are more dangerous to consume than other vegetables because leafy vegetables have larger surface areas carrying more insecticides. So whenever we eat leafy vegetables and fruits, they should be kept in water for few hours before eating.

The writer is from the department of sports medicine and physiotherapy, Guru Nanak Dev University, Amritsar.
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Automated sign verification
Deepak Bagai

PATTERN recognition is the branch of computer science in which the automatic detection of objects takes place. Automated identification of handwriting and signature verification is one of the numerous application domains of pattern recognition. With the emergence of electronic commerce, the research in the field of signature verification has gained paramount importance. Computer network security and hacking is another area of concern that has made the research efforts in the area of automated signature identification more relevant. The password system used for network security does not ensure the valid identity of a person.

The process of signature verification can be off-line or on-line. The off-line method involves the storage of the image of the signature onto the database and subsequently comparing the current signature with the stored one. The methodology for on-line recognition of signatures involves the recording of the motion of the pen as the signature is produced and the important parameters worth consideration are the probable velocity, stylus pressure and acceleration.

The image of the signature is stored on to the computer. A digital image is a matrix where each element depicts the brightness at regularly spaced intervals. These points are known as the pixels and the brightness of each pixel is called its gray level. Scanners are available these days to convert photographs to digital images. Numerous algorithms exist for processing the stroke-based recogniser.

Biometrics is another emerging area, which is being used for signature verification. Biometrics is the measurement of parameters and attributes like DNA, fingerprints, face and retina patterns, which are specific to a particular person. It is very cumbersome to duplicate the pressure variations, tilt and velocity parameters of an individual signature. Dynamic signature verification makes use of these aspects and it is not only the shape and the appearance of the signature that is prominent. Cyber-SIGN is biometrics signature identification software available in the market and is the key to the acceptability of electronic commerce on the Internet.

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High-security registration plates
Raj Kumar Aggarwal

THE Government of India has mandated that a new system of high security registration plate shall be used on all new vehicles, for vehicles already in use, this order shall come in to force two years from the date of publication of this order in the official gazette.

The high security registration plate has to be guaranteed for imperishable nature for a minimum period of five years. The registration plates will be supplied to the motor vehicle owner by the vendor against the authorisation by the State Transport Department. These will be in black colour on yellow background in case of transport vehicles and in black colour on white background in other cases. The letters of registration mark shall be in English and the letters and numerals shall be embossed and hot stamped.

To protect against counterfeiting, a chromium based hologram of the size of 20x20 mm is to be applied by hot stamping on the top left hand corner of the plate in both front and rear plates. The hologram shall contain Ashoka emblem with “Bharat Sarkar” and Govt. of India on each side, on left and right side respectively on Ashoka emblem vertically.

The permanent identification number of minimum 7 digits is to be laser branded into the reflective sheeting on the bottom left-hand side of the registration plate with the numeral size being 2.5 mm. The hot stamping film to be applied on the letters/numerals of the license number shall bear the inscription “India”.

The third registration plate in the form of a self destructive type chromium based hologram sticker shall be of the size of 100x60 mm is to be affixed on the inner side of left hand corner of the windshield of the vehicle. The details on the sticker will have the (i) name of the registering authority, (ii) registration number of the vehicle, (iii) laser branded permanent identification, (iv) engine number and (v) chassis number of the vehicle. On the bottom of the right corner of the sticker, the chromium based hologram will be applied but of smaller size of 10x10 mm. In the said sticker the registration number of the vehicle will be in the centre with a letter size of 10 mm in height. The name of registering authority would be on top part of the sticker in letter size of 5 mm, while, laser branded permanent identification number, then engine number followed by chassis number shall come in the bottom left side of the sticker with numeral size being 2.5 mm in each case.

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NEW PRODUCTS & DISCOVERIES
Never set your watch again

THE world has become a smaller place in the past few decades. Transactions take place across the world in an instant. Having a timepiece that can not only keep perfectly accurate time, but keep track of the time zones can be really helpful and convenient. Now there is a watch that scientifically gives the right time in all zones.

The Atomic Digital Watch from LaCrosse Technology is radio-controlled, maintaining its incredible accuracy by automatically tuning into the official standard frequency and time transmitter in North America. This WWVB radio signal gets its time from the most precise clock in North America based in Colorado, and transmits its signal over a 2000-mile range. With just the touch of a button, the Atomic Digital Watch gives you a selection of 24 time zones, from GMT+12h to GMT-12h, with special US time zones displayed with three characters (ATL, EST, CST, MST, PST, ALA, and HAW.) This ultra-accurate radio-controlled timepiece has a perpetual day and date calendar, signal reception indicator and is powered by a 3V lithium battery expected to last three years.

In addition to its accuracy, the watch is water resistant to three bars, or 30 meters, and has a battery-saving “OFF” function. The stainless steel butterfly clasp and removable links to adjust the band size make it a good fit.

Light pollution increasing

Astronomers have warned about the growing menace of light pollution, arguing that half the people in the European Union and 80 per cent of those in the US cannot see the Milky Way. They hope the first world atlas of light pollution, to be published soon, will help tackle the problem.

Scientists have been painfully aware for decades that light pollution, which is growing at rates of the order of 10 per cent per year, from street lamps and other artificial sources is blotting the view of heavens — a reason why new observatories are built in thinly populated areas.

But according to Pierantonio Canzzano of the University of Padua, no one knew the full extent of the problem because until now there had been no global surveys of artificial sky-brightness, a report in New Scientist said.

Cinzano and his colleagues thus studied satellite images gathered by the US Air Force Defense Meteorological satellite Programme during 1996 and 1997. PTI

Pandas with high BP

Many of the ailments suffered by China’s dwindling population of giant pandas could be connected to a problem familiar to many humans, namely high blood pressure.

Giant pandas should have regular blood pressure checks, said Chen Yucun, director of the Giant Panda Research Centre in Fuzhou, capital of Fujian province in southeastern China, is said.

With pandas not used to sitting in a chair and rolling up their sleeve, doing the test has proved a challenge, with Chen admitting the process was “difficult.”

However one 21-year-old giant panda at the research centre was successfully diagnosed with high blood pressure in March, the Xinhua report said, but after a week of treatment the reading dropped to normal levels.

Chen’s centre has achieved a series of breakthroughs, in particular connected to breeding giant pandas, of which about 1,000 remain in the wild in China. Xinhua

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SCIENCE QUIZ
J. P. Garg tests your IQ

1. Which organisation awards Nobel Prizes in Physics and Chemistry? Who are the winners of the 2001 Nobel Prize in Physics?

2. Continuing on the subject, for creating which type of matter have these scientists been awarded this coveted Prize? (Hint: This matter is partly named after an Indian scientist).

3. PLEDs are thin film displays that are produced by sandwiching a suitable polymer between two proper electrodes, placed at a short distance from each other PLED emits light when suitable current is passed through it. What is the full form of PLED?

4. When a stream of alpha particles is sent through a metallic foil, most of the particles penetrate through the foil. Can you state the basic reason for this?

5. Sometimes with a view to remove malignant tumours from the breast, the whole breast is removed surgically. What is this type of operation called?

6. US astronomer George Ellery Hale invented an instrument designed to photograph the sun in light of one particular wavelength. What was this instrument called?

7. What is the process called which is used to treat brackish water, sea water and waste effluents from factories etc. so as to produce water which can be used for general purposes?

8. This non-mechanical pump is used for the handling of highly corrosive liquids. In it the liquid is admitted to a corrosive-resistant vessel and by using compressed air it is forced into the line where it is to be delivered. What is such a pump called?

9. Noise pollution affects our body health seriously Moderate conversation has a noise level of 60 decibels. What is the noise level of a rocket?

10. NEERI is an institute that conducts research in various areas of environmental engineering. What is the full name of this institute and where is it located?

Answers

1. Royal Swedish Academy of Sciences, Stockholm, US carl E. Wieman and Eric A. Cornell, and German-citizen US-settled Wolfgang Ketterle 2. Bose-Einstein condensate in dilute gases of alkali atoms 3. Polymeric light-emitting diode 4. Bulk of the atomic space is empty 5. Mastectomy 6. Spectroheliograph 7. Reverse osmosis 8. Acid egg 9. 180 decibels 10. National Environmental Engineering Research Institute, Nagpur.

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