When Pokhran I and II test was conducted?



India’s nuclear programme kicked off just a year after the Independence in 1948 with the formation of Indian Atomic Energy Commission with Homi Jehangir Bhabha as the chairman. On May 18, 1974, India conducted its first test, a plutonium implosion device in Rajasthan’s Pokhran desert, which the government described as a ‘peaceful nuclear explosion’. Pokhran 1 was a fission nuclear explosive test.



Pokhran –II, the second nuclear weapon test, came on May 11, 1988. Scientists conducted a series of nuclear tests of advanced weapons, including a thermonuclear device, at Pokhran. It consisted of one fusion bomb and four fission bombs. The tests achieved their main objective of giving India the capability to build weapons with yields up to 200 kilotons. On May 13, 1998, then Prime Minister Atal Behari Vajpayee announced India’s new status as the world’s sixth nuclear weapons armed power.



 



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When was Mars Orbiter mission launched?



India began its space odyssey with Aryabhatta, the first unmanned satellite built by India and launched by the Soviet Union in 1975. Over the years, it has scripted a host of records with the development of powerful rockets and satellites. And India enjoys a unique status in space technology after the success of the Mars Orbiter Mission. On September 24, 2014, India became the first country to successfully place a spacecraft in Mars orbit in its first attempt. The Mars Orbiter Mission (Mangalyaan) was launched on November 5, 2013, by the Indian Space Research Organisation (ISRO). The mission cost 4.5 billion rupees, which, by Western standards, is staggeringly cheap.



Initially, the mission was to last only six months, but ISRO extended it further and the orbiter continues to send data about Mars’ geology and atmosphere. Several women scientists played significant roles in Mars Orbiter Mission. They include Ritu Karidhal and Nandini Harinath, Deputy Operations Director, Mars Orbiter Mission and Anuradha TK, Geosat Programme Director, ISRO Satellite Centre.



 



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How was PARAM supercomputer discovered?



When India built its own supercomputer, PARAM, it took the world by surprise, especially the U.S. In the 1980s, India was buying supercomputers from the U.S. but it had to fight constant battles with it over license. The then George H.W. Bush administration in the U.S. denied to export Cray supercomputer to India fearing we could use it to make nuclear weapons and missiles. This forced India to develop its own supercomputer. It set up the Centre for Development of Advanced Computing (C-DAC), with Vijay Bhatkar as its director, in Pune, in March 1988, to develop a HPC system to meet high-speed computational needs in solving scientific and other developmental problems. Within three years, Indian scientists succeeded in creating a supercomputer, PARAM 8000, with a capability of one giga floating point operations a second (1 Gflops). This was 28 times more powerful than the Cray supercomputers, India was supposed to import from the U.S. Apart from taking over the home market, PARAM attracted 14 other buyers. It set the platform for a whole series of parallel computers, called the PARAM series. The success in supercomputers catapulted India to new heights in Information and Communication Technology, space science, missile development, weather forecasting, pharmaceutical research and much more.



 



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How was Crescograph discovered?



Crescograph is a highly sensitive instrument used in the detection of minute responses by living organisms to external stimuli. It was invented by Indian plant physiologist Sir Jagadish Chandra Bose in the early 20th century. Crescograph is capable of magnifying the motion of plant tissues to about 10,000 times of their actual size, Using this, J.C. Bose found many similarities between plants and other living organisms. He demonstrated that plants are also sensitive to heat, cold, light, noise and various other external stimuli. He also invented several other instruments which would help in detecting even the slightest of change in plants. Crescograph helped make a striking discovery such as quivering in injured plants, which Bose interpreted as a power of ‘feeling’ in plants.



Also a physicist, Bose pioneered the investigation of radio and microwave optics and extensively researched the properties of radio waves. A crater on the moon has been named in his honour.



 



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How was Raman Effect discovered?



On 28 February 1928, physicist C.V. Raman led an experiment on the scattering of light, when he discovered what now is called the Raman effect. When light interacts with a molecule, the light can give away a small amount of energy to the molecule. As a result of this, the light changes its colour can act as a ‘fingerprint’ for the molecule. This phenomenon is now called Raman scattering and is the result of the Raman effect. The wavelengths and intensity of scattered lights are measured using Raman spectroscopy has a wide variety of applications in biology and medicine. It is used in laboratories all over the world to identify molecules and to analyse living cells and tissues to detect diseases such as cancer. It has been used in several research projects as a means to detect explosives from a safe distance.



Sir C. V. Raman remains the only Indian to receive a Nobel Prize in science. Three Indian-born scientists, Har Gobind Khorana, Subrahmanyan Chandrasekhar and Venkatraman Ramakrishnan, won Nobel Prizes, but they had become U.S. citizens by then.



 



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When is national science day celebrated?



India celebrates National Science Day every year on February 28 to mark Sir C.V. Raman’s discovery of the scattering of light, also known as the “Raman effect”. For his discovery, physicist Raman was awarded the Nobel Prize in Physics in 1930. The recognition put India on the global science map, but proofs to India’s scientific acumen go all the way back to the 5th century A.D, when ancient Indians developed the concept of zero. Zero, the cornerstone of modern mathematics and physics, is seen as one of the greatest innovations in human history. There are records of ancient Indians being among pioneers in irrigation, veterinary medicine, cataract surgeries and atomism. Indian astronomy also has a long history stretching from pre-historic to modern times.



Colonial era exposed a number of Indians to foreign institutions. Scientists from India also appeared throughout Europe and their work saw recognition and acceptance on a wider platform. Since Independence, India has built a number of satellites and sent probes to the Moon and Mars, established nuclear power stations, acquired nuclear weapon capability and became self-sufficient in the production of food and medicines. Not to mention the developments in meteorology, communication and Information Technology.



 



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HOW ARE FILMS PRINTED?


Printing converts the negative image of the film into a positive image on paper. Light is shone through the film onto light-sensitive paper. Passing the light through lenses makes the image larger. The print is then developed and fixed just as the film was.



Photographic paper is a paper coated with a light-sensitive chemical formula, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then developed to form a visible image; with most papers the image density from exposure can be sufficient to not require further development, aside from fixing and clearing, though latent exposure is also usually present. The light-sensitive layer of the paper is called the emulsion. The most common chemistry was based on silver salts but other alternatives have also been used.



The print image is traditionally produced by interposing a photographic negative between the light source and the paper, either by direct contact with a large negative (forming a contact print) or by projecting the shadow of the negative onto the paper (producing an enlargement). The initial light exposure is carefully controlled to produce a gray scale image on the paper with appropriate contrast and gradation. Photographic paper may also be exposed to light using digital printers such as the Light-jet, with a camera (to produce a photographic negative), by scanning a modulated light source over the paper, or by placing objects upon it (to produce a photogram).



Despite the introduction of digital photography, photographic papers are still sold commercially. Photographic papers are manufactured in numerous standard sizes, paper weights and surface finishes. A range of emulsions are also available that differ in their light sensitivity, color response and the warmth of the final image. Color papers are also available for making color images.



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HOW IS FILM DEVELOPED?


After an image has been recorded on light-sensitive film in a camera, the film is moved along, so that the next photograph will be taken on a fresh piece of film. No more light must hit the exposed film until it is developed, or the picture would be spoiled. When all the photographs on a roll of film have been taken, the film is wound into its case, which is lightproof. The development process then takes place in a darkroom, or in a specially made machine.



Photographic processing or photographic development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.



All processes based upon the gelatin-silver process are similar, regardless of the film or paper’s manufacturer. Exceptional variations include instant films such as those made by Polaroid and thermally developed films. Kodachrome required Kodak’s proprietary K-14 process. Kodachrome film production ceased in 2009, and K-14 processing is no longer available as of December 30, 2010. llfochrome materials use the dye destruction process.



All photographic processing use a series of chemical baths. Processing, especially the development stages, requires very close control of temperature, agitation and time.




  1. The film may be soaked in water to swell the gelatin layer, facilitating the action of the subsequent chemical treatments.

  2. The developer converts the latent image to macroscopic particles of metallic silver.

  3. A stop bath, typically a dilute solution of acetic acid or citric acid, halts the action of the developer. A rinse with clean water may be substituted.

  4. The fixer makes the image permanent and light-resistant by dissolving remaining silver halide. A common fixer is hypo, specifically ammonium thiosulfate.

  5. Washing in clean water removes any remaining fixer. Residual fixer can corrode the silver image, leading to discolouration, staining and fading.



The washing time can be reduced and the fixer more completely removed if a hypo clearing agent is used after the fixer.




  1. Film may be rinsed in a dilute solution of a non-ionic wetting agent to assist uniform drying, which eliminates drying marks caused by hard water. (In very hard water areas, a pre-rinse in distilled water may be required – otherwise the final rinse wetting agent can cause residual ionic calcium on the film to drop out of solution, causing spotting on the negative.)

  2. Film is then dried in a dust-free environment, cut and placed into protective sleeves.



Once the film is processed, it is then referred to as a negative. The negative may now be printed; the negative is placed in an enlarger and projected onto a sheet of photographic paper. Many different techniques can be used during the enlargement process. Two examples of enlargement techniques are dodging and burning. Alternatively (or as well), the negative may be scanned for digital printing or web viewing after adjustment, retouching, and/or manipulation.



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HOW DOES A CAMERA WORK?


A camera is a lightproof box containing light-sensitive film. To take a picture, the photographer presses a button to open a shutter and let light pass through the aperture, a hole in the front of the camera. The camera’s lens focuses the light so that it forms a sharp image on the photographic film, just as the lenses in our eyes focus the light onto our retinas. Then the shutter closes again so that no more light reaches the film. The whole process usually takes just a fraction of a second.



A still film camera is made of three basic elements: an optical element (the lens), a chemical element (the film) and a mechanical element (the camera body itself). As we'll see, the only trick to photography is calibrating and combining these elements in such a way that they record a crisp, recognizable image.



There are many different ways of bringing everything together. In this article, we'll look at a manual single-lens-reflex (SLR) camera. This is a camera where the photographer sees exactly the same image that is exposed to the film and can adjust everything by turning dials and clicking buttons. Since it doesn't need any electricity to take a picture, a manual SLR camera provides an excellent illustration of the fundamental processes of photography.



The optical component of the camera is the lens. At its simplest, a lens is just a curved piece of glass or plastic. Its job is to take the beams of light bouncing off of an object and redirect them so they come together to form a real image -- an image that looks just like the scene in front of the lens.



But how can a piece of glass do this? The process is actually very simple. As light travels from one medium to another, it changes speed. Light travels more quickly through air than it does through glass, so a lens slows it down.



When light waves enter a piece of glass at an angle, one part of the wave will reach the glass before another and so will start slowing down first. This is something like pushing a shopping cart from pavement to grass, at an angle. The right wheel hits the grass first and so slows down while the left wheel is still on the pavement. Because the left wheel is briefly moving more quickly than the right wheel, the shopping cart turns to the right as it moves onto the grass.



The effect on light is the same -- as it enters the glass at an angle, it bends in one direction. It bends again when it exits the glass because parts of the light wave enter the air and speed up before other parts of the wave. In a standard converging, or convex lens, one or both sides of the glass curves out. This means rays of light passing through will bend toward the center of the lens on entry. In a double convex lens, such as a magnifying glass, the light will bend when it exits as well as when it enters.



This effectively reverses the path of light from an object. A light source -- say a candle -- emits light in all directions. The rays of light all start at the same point -- the candle's flame -- and then are constantly diverging. A converging lens takes those rays and redirects them so they are all converging back to one point. At the point where the rays converge, you get a real image of the candle. In the next couple of sections, we'll look at some of the variables that determine how this real image is formed.




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WHO WAS THE FIRST PHOTOGRAPHER?


The first person to take a photograph was a Frenchman, Joseph Nicephore Niepce, in 1822. However, as is often the case with new inventions, many other scientists had been experimenting with light, lenses and light-sensitive chemicals. Working with Niepce was a man called Louis Daguerre, who later improved on Niepce’s process. Some early photographs were called daguerreotypes.



Around 1717 Johann Heinrich Schulze captured cut-out letters on a bottle of light-sensitive slurry, but he apparently never thought of making the results durable. Around 1800 Thomas Wedgwood made the first reliably documented, although unsuccessful attempt at capturing camera images in permanent form. His experiments did produce detailed photograms, but Wedgwood and his associate Humphry Davy found no way to fix these images.



In the mid-1822s, Nicephore Niepce first managed to fix an image that was captured with a camera, but at least eight hours or even several days of exposure in the camera were required and the earliest results were very crude. Niépce's associate Louis Daguerre went on to develop the daguerreotype process, the first publicly announced and commercially viable photographic process. The daguerreotype required only minutes of exposure in the camera, and produced clear, finely detailed results. The details were introduced to the world in 1839, a date generally accepted as the birth year of practical photography. The metal-based daguerreotype process soon had some competition from the paper-based calotype negative and salt print processes invented by William Henry Fox Talbot and demonstrated in 1839 soon after news about the daguerreotype reached Talbot. Subsequent innovations made photography easier and more versatile. New materials reduced the required camera exposure time from minutes to seconds, and eventually to a small fraction of a second; new photographic media were more economical, sensitive or convenient. Since the 1850s, the collodion process with its glass-based photographic plates combined the high quality known from the Daguerreotype with the multiple print options known from the calotype and was commonly used for decades. Roll films popularized casual use by amateurs. In the mid-20th century, developments made it possible for amateurs to take pictures in natural color as well as in black-and-white.



The commercial introduction of computer-based electronic digital cameras in the 1990s soon revolutionized photography. During the first decade of the 21st century, traditional film-based photochemical methods were increasingly marginalized as the practical advantages of the new technology became widely appreciated and the image quality of moderately priced digital cameras was continually improved. Especially since cameras became a standard feature on smartphones, taking pictures (and instantly publishing them online) has become a ubiquitous everyday practice around the world.



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HOW IS A HARDBACK BOOK COVER MADE?


Glueing, sewing or stapling pages together and placing them within a cover is called binding. Several pieces of card and paper are required to bind a hardback book. It is also possible to add bookmark ribbons and little pieces of fabric called headbands at the top and bottom of the spine (back) of the book.



A hardcover or hardback (also known as hardbound, and sometimes as case-bound) book is one bound with rigid protective covers (typically of binder’s board or heavy paperboard covered with buckram or other cloth, heavy paper, or occasionally leather). It has a flexible, sewn spine which allows the book to lie flat on a surface when opened. Following the ISBN sequence numbers, books of this type may be identified by the abbreviation Hbk.



Hardcover books are often printed on acid-free paper, and they are much more durable than paperbacks, which have flexible, easily damaged paper covers. Hardcover books are marginally more costly to manufacture. Hardcovers are frequently protected by artistic dust jackets, but a "jacketless" alternative has increased in popularity: these "paper-over-board" or "jacketless hardcover" bindings forgo the dust jacket in favor of printing the cover design directly onto the board binding.



Hardcovers typically consist of a page block, two boards, and a cloth or heavy paper covering. The pages are sewn together and glued onto a flexible spine between the boards, and it too is covered by the cloth. A paper wrapper, or dust jacket, is usually put over the binding, folding over each horizontal end of the boards. Dust jackets serve to protect the underlying cover from wear. On the folded part, or flap, over the front cover is generally a blurb, or a summary of the book. The back flap is where the biography of the author can be found. Reviews are often placed on the back of the jacket. Many modern bestselling hardcover books use a partial cloth cover, with cloth covered board on the spine only, and only boards covering the rest of the book.



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WHY CAN THE NUMBER OF PAGES IN A BOOK USUALLY BE DIVIDED EXACTLY BY 16?


Pages in a book are not printed one by one. They are printed on huge sheets of paper that then pass through another machine to be folded. When the book is bound (put into its cover), the edges of the pages are cut on a guillotine. A piece of paper folded in half creates four pages. Larger sheets of paper are folded to make 16, 32 or even 64 pages.



Most booklets are created with the Saddle-Stitch binding method. This method uses printed sheets that are folded and nested one inside the other and then stapled through the fold line with wire staples. The staples pass through the folded crease from the outside and are clinched between the centermost pages. The result is a very simple yet professional looking document.



Despite its relative simplicity, saddle-stitch booklets often pose a challenge for someone new to graphic design. This is because the page set-up for saddle-stitched booklets requires a different approach than for other types of bound books.



Saddle-stitched booklets are constructed of folded sheets. As such, each folded sheet joined within the finished booklet will form four pages of the booklet. This means the page count of every saddle-stitched booklet must always be a multiple of four (4). It is not possible to create a 7-page, 10-page, or 25-page saddle-stitched booklet. All saddle-stitched booklets must contain 4 pages, 8 pages, 12 pages, 16 pages, 20 pages, 24 pages and so on. Even if a page in the booklet is blank, it still counts as a page.



Needless to say, creating the layout file properly at the onset will help optimize your booklet’s press run…saving time, effort, and expense for all involved. The software you use to create the booklet will likely give you file layout choices, such as Reader Spreads or Printer Spreads. Because printing presses and production methods vary from print shop to print shop, do not automatically set up your booklet file in a particular spread or configuration without first consulting the printer you intend to use for producing your booklet.




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WHAT IS A TYPEFACE?


A typeface is an alphabet that has been specially designed for printing. It can usually be used in a variety of sizes and styles. The typeface chosen has a huge effect on how a printed page looks. Some typefaces are designed to be easy to read. Others are meant to catch the eye in headings and titles. Today, computers make it easy to manipulate type, stretching it or squashing it, for example, to create special effects. It is also easy to adapt typefaces or create your own. Each set of letters, numbers and symbols in a type-face is called a font.



A typeface is a set of characters of the same design. These characters include letters, numbers, punctuation marks, and symbols. Some popular typefaces include Arial, Helvetica, Times, and Verdana. While most computers come with a few dozen typefaces installed, there are thousands of typefaces available. Because they are vector-based (not bitmaps), typefaces can be scaled very large and still look sharp. The term "typeface" is often confused with “font,” which is a specific size and style of a typeface. For example, Verdana is a typeface, while Verdana 10 pt bold is a font. It's a small difference, but is good to know.



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WHAT IS PRINTING REGISTRATION?


The page to be printed passes between inked rollers or plates four times, each time with a different coloured ink being used. In order to make sure that the final image is clear and sharp, the four printings must line up exactly on top of each other. This is known as registration. Registration marks, at the corners of a page, help the printer to position the images accurately. You may have seen a strip of coloured shapes on the edge of a printed food- packet. These also enable the printer to see at a glance if the four printings have been properly positioned.



Four color process printing uses four ink colors – Cyan, Magenta, Yellow and Black. These four colors are applied one after the other on a printing press. They overlap each other in various concentrations on the paper to create the visual effect we know as full color printing. Because these four colors combine to make an image, the proper registration of these colors is crucial to produce a sharp image. Even a slight position shift in one of the four colors will cause the printed image to appear blurred or fuzzy.



For the same reason as above, proper registration is also a concern for two-color and three-color printing. One-color printing is not concerned with ink registration since only one ink color is used (but like all printing jobs, the ink must be properly registered to the paper so that the image transfers to its intended location – i.e., not closer to one edge of the paper than intended).



A term related to ink registration is Close Registration, which means that the printed image has two or more ink colors that touch or are very near each other. By its nature, four color process printing always has close registration. Two-color and three-color printing may or may not have close registration, it just depends on the intended design. Jobs with close registration should be printed in a single pass through a printing press to ensure the ink colors align properly with each other.



Proper registration is also an important consideration for multi-part forms. Each ply of the form must be assembled in the same relative position so entries made on the top ply transfer properly to each subsequent ply. Have you ever filled out a multi-part form only to notice that what you wrote on the top was slightly out of position on a different ply? This is because the form’s ply-to-ply registration was off.




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HOW ARE DIFFERENT TONES OF COLOUR PRINTED?


Some printed images use one solid colour. These words are printed in solid black ink, for example. The dots are so close together that no background colour shows through. Using increasingly widely spaced dots creates the impression of paler tones of grey.



The color model (process color, four color) is a subtractive color model, based on the CMY color model, used in color printing, and is also used to describe the printing process itself. CMYK refers to the four ink plates used in some color printing: Cyan, Magenta, Yellow, and Key (black).



The CMYK model works by partially or entirely masking colors on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected. Such a model is called subtractive because inks "subtract" the colors red, green and blue from white light. White light minus red leaves cyan, white light minus green leaves magenta, and white light minus blue leaves yellow.



In additive color models, such as RGB, white is the "additive" combination of all primary colored lights, while black is the absence of light. In the CMYK model, it is the opposite: white is the natural color of the paper or other background, while black results from a full combination of colored inks. To save cost on ink, and to produce deeper black tones, unsaturated and dark colors are produced by using black ink instead of the combination of cyan, magenta, and yellow.



With CMYK printing, half-toning (also called screening) allows for less than full saturation of the primary colors; tiny dots of each primary color are printed in a pattern small enough that humans perceive a solid color. Magenta printed with a 20% halftone, for example, produces a pink color, because the eye perceives the tiny magenta dots on the large white paper as lighter as and less saturated than the color of pure magenta ink.



Without half-toning, the three primary process colors could be printed only as solid blocks of color, and therefore could produce only seven colors: the three primaries themselves, plus three secondary colors produced by layering two of the primaries: cyan and yellow produce green, cyan and magenta produce blue, yellow and magenta produce red (these subtractive secondary colors correspond roughly to the additive primary colors), plus layering all three of them resulting in black. With half-toning, a full continuous range of colors can be produced.



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