Fri 15 Jan 2010, 14:20 PM | Posted by admin
Tags: News, Science
Planetary Society, India in association Andhra Pradesh State Council of Science and Technology (APCOST) and Dr.K.V.Rao Scientific Society as part of Annular Solar Campaign 2010 with a motive to create awareness among school students has undertaken state wide activities with the help of 23 District Coordinators and 5 Regional coordinators of the APCOST. Activities like Space Simulator (Students created simulations of solar eclipse as seen from 50 different countries), Media Discussions on the subject and others are already planned. Importantly at State Level Press conference Compact Disk, Poster, Presentation of Simulated Animations of Eclipse with experts like Prof. G. Yellaiah, Dept of Astronomy, O.U., N. Sri Raghunandan Kumar, General Secretary were conducted.
Brief about Solar Eclipse: A solar eclipse occurs when the Moon passes between the Sun and the Earth such a way that the Sun is wholly or partially obscured. This can only happen during a new moon, when the Sun and Moon are in conjunction as seen from the Earth. Annular Solar Eclipse: An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the outline of the Moon. Antumbra: This is that part of Moon’s shadow from which Sun appears larger than the Moon which is seen in complete silhouette. An annular eclipse is seen by an observer when he is located on path of antumbraPlanetary Society, India in association Andhra Pradesh State Council of Science and Technology (APCOST) and Dr.K.V.Rao Scientific Society as part of Annular Solar Campaign 2010 with a motive to create awareness among school students has undertaken state wide activities with the help of 23 District Coordinators and 5 Regional coordinators of the APCOST. Activities like Space Simulator (Students created simulations of solar eclipse as seen from 50 different countries), Media Discussions on the subject and others are already planned. Importantly at State Level Press conference Compact Disk, Poster, Presentation of Simulated Animations of Eclipse with experts like Prof. G. Yellaiah, Dept of Astronomy, O.U., N. Sri Raghunandan Kumar, General Secretary were conducted. Brief about Solar Eclipse: A solar eclipse occurs when the Moon passes between the Sun and the Earth such a way that the Sun is wholly or partially obscured. This can only happen during a new moon, when the Sun and Moon are in conjunction as seen from the Earth. Annular Solar Eclipse: An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the outline of the Moon. Antumbra: This is that part of Moon’s shadow from which Sun appears larger than the Moon which is seen in complete silhouette. An annular eclipse is seen by an observer when he is located on path of antumbra Importantly as part of this campaign “Student Space Simulators” project is being carried out at Hyderabad involving school students from three regions of the state. DETAILS OF ANNULAR ECLIPSE ON 15th, January, 2010 : Annular Solar Eclipse will occur on 15th January, 2010. This eclipse is visible partially in major parts of the country. This is first Solar Eclipse of the Year and best until year 2019 Dec 26th. As the next solar eclipse in 2011 on Jan 4 is visible to people in Northern parts of the country and few places in Gujarat. Whereas the solar eclipse in 2016 though visible in India begins and lasts only for few minutes close to horizon in early hours of March 9 Path of the Eclipse : The annular path of the eclipse will pass through the region covering southern tip of Chad, the Central African Republic, the northern Democratic Republic of Congo, Uganda, Kenya, the southern tip of India, northern Sri Lanka, the south-eastern tip of Bangladesh, Myanmer and south-eastern China. After leaving Africa, the path crosses the Indian Ocean where the maximum duration of annularity reaches 11 min 08 s. It will be seen as annular within a narrow stretch of 333 km width covering across Central Africa, Maldives South Kerala, South Tamil Nadu, North Sri Lanka, Burma and China. Whereas this eclipse would be seen as partial from eastern Africa, south-east Europe, the Middle East, and south-east Asia Importantly the duration of annularity which is 11 minutes 8 seconds during this annular eclipse on 15th Jan,2010 will not be exceeded for over 1000 years (3043 Dec 23). Timings of the Eclipse : World Wide: Astronomically speaking the phenomena of Eclipse begins (first contact with earth) at 9.35 a.m. and ends at 3.38 p.m (last contact with earth) in the evening. In which the Central Phase of Eclipse begins at 10. 48 a.m. and Ends at 2.25 p.m. Wherein Greatest Eclipse Phase (when the eclipse is maximum occurs) at 12.36 p.m The duration of Annular Phase of Eclipse at maximum phase is 11 minutes and 4 seconds when people would witness sun as bright outline around moon disk like a ring. Timings – Across India : However in India people in southern part of India will be the first to see the eclipse as the path of eclipse traverses across India before entering Bangladesh, Burma. People in western and south India would see the beginning of eclipse between 11.00 to 11.30 a.m. Whereas people from central to north India would see the beginning of eclipse from 11.30 to 12 noon. Importantly people in eastern part of India would see the beginning from 12 Noon onwards. People in northern eastern states of India would see the eclipse beginning from 12.15 onwards. In India Kavaratti island in Lakshadweep would be one of the first to see the beginning of eclipse at 10.55 a.m. Whereas Dibrugarh would be one of the last to see the beginning (at 12.29 a.m.) or ending (3.39 p.m. ) of eclipse. Timings in Andra Pradesh - Percentage of Visibility when eclipse is maximum : In Hyderabad the solar eclipse begins at 11.29 a.m. and Ends at 3.15 p.m. At Nellore eclipse begins at 11.28a.m and ends at 3.16 p.m. Kurnool Eclipse begins at 11.25 a.m. and ends at 3.14 p.m. Rajmundry eclipse begins at 11.38 a.m. and ends at 3.20 p.m. Vijayawada eclipse begins at 11.34 a.m. and ends at 3.18 p.m. Vizag eclipse begins at 11.44 and ends at 3.22 p.m. Tirupati 11.23 a.m. to 3.14 p.m. The Percentage of Sun’s Disk at when eclipse is maximum (around 1.32 p.m) is Rajahmundry 83%, Vijayawada at 82%, Kurnool 79%. For Hyderabad its 77 %. Whereas Nellore District in our state is best place to witness this spectacle where covering of Sun’s disc by Moon would be 85%. Percentage of Visibility – The More one his away from the Annularity Path – Less the Percentage of Sun Disk Coverage – at Maximum Phase : However this event can be seen only partially from major parts of the country. Depending on the location of the observer one can see the sun’s disk being covered from 42 % or less as one gets away from the ant-umbral path of eclipse. When the eclipse reaches the maximum point. For an observer in Hyderabad would see 77 % of Sun’s disk. Whereas an observer in Ahmadabad can see only 56% or 42 % in case of observer in Jammu who is far away from the path of annularity. Even closely a person observing from Chennai would see only 89 % of sun being covered, whereas one from thanjavur being in antumbral path would enjoy Moon’s entire disk silhouetted against the Sun. Which allows him to see sun as bright ring, or annulus, surrounding the outline of the Moon. Best Places to be at : Some of the best places through watch this eclipse where path of annularity passes is Karaikal, Madurai, Nagapattinam, Nagercoil, Rameswaram, Sivaganga, Tanjore, Thiruvarur, Tirunelveli, Trivandrum. i.e. is from these places and around people would witness Moon’s entire disk silhouetted against the Sun. Rameshwaram would witness highest duration during maximum phase i.e. 10 min 8 sec followed by Kanyakumari where it will be 9 min 58 seconds. Importance of 15 Jan,2010 Eclipse – One who misses now need to wait for 9 years - Last prominent Solar Eclipse until 2019 -: 2011 4th January: this eclipse is visible to people in north India and few places in Gujrat. This eclipse is partial. 2016 9th March : The next opportunity to observe solar eclipse which is partial will occur on 9th March 2016 covering major parts of country . However eclipse begins well before sunrise in the morning and lasts upto 6.47 a.m when sun is close to horizon. This is very difficult to appreciate. 26th December, 2019: The best next prominent opportunity covering larger parts of the country of a Solar Eclipse will only happen on 26th December, 2019 which begins late in early morning when sun is sufficiently above horizon and continuing up to noon. This means people in major parts of India missing the opportunity to observe the eclipse on 15th January, 2010 will not have opportunity to observe the solar eclipse for next 9 years until year 2019. Importantly the duration of annularity which is 11 minutes 8 seconds during this annular eclipse on 15th Jan,2010 will not be exceeded for over 1000 years (3043 Dec 23). Tips for Observations: Solar eclipse should not be directly with naked eye or things like x ray films etc. As it may cause injury to eye. Hence people should use certified solar filters. Or use indirect projection method i.e. people can take a white paper and make a round hole into it. While facing one’s back toward sun one should hold the paper in such a way that Sun rays pass through the hole and fall onto wall. This way one would see projected image of sun light slowly getting darken as the eclipse progresses and get clear once the eclipse is complete.
Fri 14 Aug 2009, 12:15 PM | Posted by admin
Tags: Articles, Internet, Science
To commemorate the 90th birth anniversary of Vikram Sarabhai, the father of the Indian space programme, the Indian Space Research Organisation (ISRO) on Wednesday unveiled its most ambitious people-oriented project yet. Bhuvan – Sanskrit for ‘Earth’ – is a remote-sensing 3D image portal that promises to take on the likes of popular virtual globe-mapping applications such as Google Earth and Wikimapia. What’s more, it is technically superior on paper! The most interested feature for users will be the ability of Bhuvan to zoom far closer than the aerial view from a chopper. While Google Earth restricts zooming to 200 metres and Wikimapia goes up to 50 metres, ISRO’s new technology will be able to render images from up to 10 metres, which means you can easily see details up to a three-floor high building and also add information. The other important feature is that Bhuvan uses seven satellites (including ISRO’s Resourcesat-1, Cartosat-1 and Cartosat-2) to provide images, as well as time-stamping them for multiple views from the same satellite. This provides images from different angles apart from the default top-down perpendicular view, thus enriching the user experience. "Thus, Bhuvan represents, in essence, the whole of India on your computer. It enables users to fly from space to street level, to grab, spin and zoom down to any place," says ISRO. Another significant aspect of Bhuvan is that due to its focus on the Indian sub-continent, it will be able to offer better updates of the images. ISRO will update images for the program once every year, as compared to Google’s 4-year updates. As it keeps updating its database with more recent and higher resolution images, Bhuvan eventually promises to offer real-time data and images. The information on Bhuvan will be layered, providing the option of viewing filtered data. ISRO plans to integrate inputs from local players like farmers, fishermen, etc who know the area in and out. This is for the primary reason to make it of more use to the general public. Of course, while this is plenty of cause to celebrate, ISRO’s being an Indian government organisation was stamped in bold letters by the fact that Bhuvan’s portal at http://bhuvan.nrsc.gov.in has been down since morning. Is this an ominous sign of things to come or just that the servers couldn’t handle the tremendous amounts of hits it must have received? We strongly hope it’s the latter…
Sat 14 Mar 2009, 16:27 PM | Posted by admin
Tags: Science
A new E300 million plant in Denmark combines advanced control, three dimensional design,clean-in-place technology, water purification and sterilisation in one insulin production and purification plant. eLab takes a look inside.
When IBP decided it wanted a new insulin plant in Kalundborg, Denmark, it pulled together suppliers from around the world.
In charge of the project was the Danish design and engineering contractor Novo Nordisk Engineering (NNE), which used its own amodular plant' construction concept.
The plant's main 200-metre long production hall has nine auxiliary plants located as side buildings feeding the central dual stream production lines. These auxiliary facilities include a CIP cleaning plant, a cooling/refrigeration plant, an HPLC column and a high capacity water purification plant � prior to ozone sterilisation � plus laboratories and workshops.
All these services are supplied to the required points on the main fermentation, purification and crystallisation production lines, which can mean up to 300 separate connection circuits.
The factory computer system co-ordinates, controls and records the production process, according to any of the 800 recipes established, selecting from 17 000 operations. During the process, extensive quality data is gathered and used to generate a batch report for each processing area, an essential requirement for pharmaproduction.
"Managing such a project, involving800 workers on site, and 500 NNE staff, has been an enormous challenge,“ said Ole Regnar Hansen, project director. "All of the many NNE skills and know-how have been utilised. NNE also undertook 90 per cent of the huge task of qualifying this large pharmaceutical plant. NNE md Hans Ole Voigt added: "This project has been a unique catalyst for growth, providing us with invaluable know-how and skills thatenhance our capabilities for future pharma projects.“
Advanced control and records
Hundreds of instructions and procedures that must be followed to the letter have been drawn up to ensure that all the processes used in the Insulin production are carried out correctly. In order to document that this has indeed been done, numerous items of data must be gathered routinely, and many tests and checks made as part of each batch report.
"Most of that kind of work used to be done on paper, but the bulk of it will be handled electronically in the new factory,“ said Leif Poulsen, department manager for automation. "The factory computer system is designed to coordinate and control the complex production process and automatically generate the necessary batch documentation. This eliminates a lot of the routine work and lets operators concentrate on making sure that production is carried out optimally.“
The computer system helps make daily work more interesting and is also an effective way of ensuring that production is carried out in accordance with the procedures in force � procedures for processing, quality control and cleaning. Technically, the procedures are defined as electronic recipes in a database, where they are maintained and approved electronically by the quality assurance department before being used in production. When production starts, the relevant information is sent from the recipes to the processing system, which ensures that the individual steps in the process are carried out in the right order.
During the production process, a lot processing and quality data are gathered and used as the basis for generating a batch report for each processing area. The batch report is as important as the product being made, because the product cannot be released without documentation. The system contains an enormous amount of data: 600 recipes have been drawn up with related reports covering more than17 000 different operations with a total of about600 000 associated parameter values.
In the past, recipes and reports were often programmed as part of the processing management system, but this solution was not viable for IBP due to the huge volume of data.
"We have implemented a data-driven solution that defines recipes and reports as data, which users can easily change as needed. That provides great flexibility in terms of future changes and also reduces the need for subsequent revalidation. Italso gives the factory a agold mine' of easily accessible processing data that can be used foron-going optimisation of operations,“ explained Poulsen.
HPLC columns, 3D design
Column processes are a known purification stage in Insulin manufacture. The large HPLC column facilities in the IBP plant are a good example of the value of project recycling, modular engineering, and external construction of modules parallel withon-site building work.
"The HPLC columns could largely be constructed on the basis of existing columns by copying substantial parts of the design and the efficient process technologies, thereby minimising development work,"" said Jim Knudsen, the engineer responsible for this part of the project. The HPLC columns were modularised with a view to further recycling in future projects, and also to reduce overall construction time by enabling parallel activities such as machine and instrument installation to be carried out as building work progressed.
"We took the flat, 2D pipe design from an earlier project and, using the AutoPlant program, literally superimposed a new and smarter 3D model on top of it. We then did the necessary redesign work, which also included process and health andsafety improvements,“ he added. Construction of the modules, both steelwork and instrumentation assembly, took place outside the plant building.
The modules were delivered to the plant almost complete and installed in place immediately prior to closure of the building exterior. Once the last cables and pipes were installed, final qualification of the columns could start. This was a considerable job of work as it involved some of the most advanced equipment on the IBP plant. "I would estimate that we saved around four months using modular engineering rather than conventional procedures, a saving that is directly reflected in the final completion date,“ noted Knudsen.
The many other pipe systems in the IBP project were also constructed using smart, 3D design principles to create a three-dimensional pipe and equipment model to predefined specifications. This enabled parts lists and working drawings to be generated for direct use in the pipe installation.
A 3D model of building structures, ventilation, cable trays and other major components was also created, enabling potential clashes to be identified as early as the design stage.
This was hugely important for the project construction phase when sorting out problemscan rapidly impact on the completionschedule.
The 3D model made it possible to introduce a degree of modularisation by enabling well-defined process units to be isolated from the rest of the plant, put out to tender, and completed by a subcontractor.
CIP cleaning
Equipment cleaning is fully automated via a sophisticated, centrally managed cleaning in place (CIP) facility. CIP means that cleaning is carried out by permanently connected units � in this case, located at more than 300 points in the process, right from fermentation, to insulin ready to be filled into pens.
How could such a massive job have been done in such a short space of time? "Instead of designing more than 300 tailored CIP solutions, our challenge was to build one large system with so many abuttons' that all 300 operators could use it. This was a whole new approach to CIP,“ said Dirk Anthonisen, automation coordinator, who has been involved since the start of the project.
The CIP process was divided into three phases: preparing cleaning fluids, mixing, and collecting used fluids for online measuring. A single program manages the 24 local depots where users can collect cleaning fluids.
"Some liken the new CIP facility to a piece of furniture with lots of drawers to open as needed,“ says Claes Bloch Larsen, CIP project manager.The system is considerably more flexible than traditional CIP solutions, because the individual user recipes can easily be changed and modifications made to apply everywhere. Novo Nordisk is so satisfied with the new CIP plant at IBP inKalundborg that it plans to install a similar set-upat its next large factory.
The equipment was produced and tested with water offsite at the supplier's premises to ensure the highest possible efficiency. The same software module is used throughout the plant, a major advantage for reporting and cleaning validation because the batch reports and their data are compiled to the same standards, regardless of location in the production process.
NNE and GEA Liquid Processing Scandinavia established the joint venture company GEANNE I/S, which supplied the full solution, from theseven-metre high preparation tanks to the last little test tap, including all design, management and validation work.
"We supplemented each other's strengths and gained a sense of shared responsibility for the project. We had a common interest in coordinating the work as well as possible and solving problems underway,“ added Claes Bloch Larsen.
Water purification and sterilisation
Insulin production requires huge amounts of water, both raw water for fermentation and recovery and purified water for the subsequent processing stages and CIP.
For IBP, a team of employees designed what was to be one of the world's largest water purification plants. Anders Kofoed Nielsen, project manager,saw coordinating with all the other subprojects as a major challenge: "All production areas need water, so we had to be ready first. In order to meet the delivery deadline for this type of facility, we were also the first team to alock' our design. As we didn't yet know the exact operational requirements forthe finished factory, we had to rely on calculated estimates.“
The estimates were obviously fairly accurate, since after the first year of testing, only a few adjustments have been necessary relative to the actual pattern of consumption. As something completely new, the raw water plant is prepared for ozone sterilisation � a technology previously unknown in Denmark. Not only are ozone sterilisation systems cheaper and moreenvironment-friendly than heat sterilisation, theyput less strain on the plant as it is not subjected to thermal stress. As the water purification plant was one of the first systems up and running, it was also a guinea pig for many of the other systems thatwere added later, such as the factory management system, automation, and the entire qualification apparatus.
More about NNE is available on tel 0045 4444 7777, fax 0045 4444 3777, email contact@nne.dk, www.nne.dk
Tue 3 Mar 2009, 13:57 PM | Posted by admin
Tags: Science
The luminous appearance of a cat's eyes in the dark is due to the reflection of light by the tapetum lucidum, which is part of the membranous layer between the retina and the outer covering of the pupils of the eyes. This remarkable layer is distinctly differentiated from the choroid layer only in certain animals. It is the tapetum lucidum that enables members of the feline family and other nocturnal animals to see even when there is very little light. Some authorities believe this layer reflects the light rays through the retina a second time. In the domestic cat the tapetum lucidum is brilliant green or blue in color and has a metallic luster. The well known glare is especially noticeable when artificial light is thrown on a cat in a dark corner, or when a cat in a dark place is observed through an opening, light entering the darkness through the opening being reflected from the cat's eyes as from a mirror.
Tue 3 Mar 2009, 13:52 PM | Posted by admin
Tags: Science
Eclipse, is partial or total obscuring of one celestial body by the shadow of another. There are two types of eclipse which are commonly known the lunar eclipses, which occur when the earth blocks the sun's light from the moon, and solar eclipses, occurring when the moon blocks the sun's light from a small portion of the earth. Occasionally a double or binary star system is aligned so that one star eclipses the other as seen from the earth; these stars are known as eclipsing binaries. the eclipses of Jupiter's satellites is also an important scientific event; in 1675 the Danish astronomer Ole Roemer used these eclipses to calculate the speed of light. Observations of starlight passing near the sun during the 1919 solar eclipse were of particular value in validating Einstein's general theory of relativity.
SOLAR ECLIPSE
A total solar eclipse can occur only when the moon is in its new phase. At this time the moon is between the sun and the earth and cannot be seen until it moves across the sun's disk. At the onset of totality, parts of the sun may be seen shining brightly between the high points of the moon's irregular edge, a phenomenon known as Baily's beads; the disk of the moon appears black and is surrounded by the sun's corona, out of which shoot immense, flame like spurts called prominences. The sky darkens to twilight, the brightest stars become visible, and there is a noticeable drop in temperature. Baily's beads are seen again as the sun reappears and the sky grows lighter.
At apogee (when the moon is at its farthest point from the earth) the umbra of its shadow is too short to reach the earth's surface, causing the apparent diameter of the sun's disk to be larger than that of the moon. Where the moon would otherwise block the sun entirely, now the sun is seen as a bright ring completely surrounding the moon's disk; this eclipse is known as an annular, or ring, eclipse.
The longest possible duration of totality for a solar eclipse is 7 min, 40 sec at or near the equator when the sun is directly overhead; the duration decreases with increasing latitude. The eclipse of June 20, 1955, lasted 7 min, 8 sec, which was the longest duration of totality in 1,238 years; an eclipse almost as long occurred on July 11, 1991.
LUNAR ECLIPSE
Since the earth and moon shine only by the reflected light of the sun, each casts a shadow into space in the direction away from the sun. The shadow consists of a cone-shaped area of darkness called the umbra, where all light from the sun is cut off, and a larger area of partial darkness called the penumbra, which surrounds the umbra and receives light from a part of the sun's disk.
Lunar eclipses can occur only when the moon is in its full phase, i.e., when the earth is between the sun and the moon. These eclipses may be total or partial, depending on whether the moon passes completely into the umbra of the earth's shadow or remains partly in the penumbra. Since the moon cuts the umbra close to the base, it can experience long periods of total eclipse ranging up to 1 hr, 42 min. A partial eclipse (when it passes through the penumbra) can last more than 2 hr, and the entire lunar eclipse may continue for as long as 4 hr. Some light is refracted, or bent, by the earth's atmosphere into the umbra, so that the moon at totality, instead of appearing black, ranges from a dull gray to a coppery color, depending on the amount of dust in the earth's atmosphere.
MORE ABOUT ECLIPSES
If the plane of the moon's orbit about the earth coincided with that of the earth about the sun, a solar eclipse would be observed each month when the moon is new and a lunar eclipse when the moon is full. However, the moon's orbital plane is tilted at an angle of about 5°10' to the earth's orbital plane, making eclipses possible only when the three bodies are aligned (at new or full moon) and when the moon is crossing the earth's orbital plane (at a point called the node).
Within a given year, a maximum of seven eclipses can occur, either four solar and three lunar or five solar and two lunar. Despite the fact that there are more solar than lunar eclipses each year, over time many more lunar eclipses are seen at any single location on earth than solar eclipses. This occurs because a lunar eclipse can be seen from the entire half of the earth facing the moon at that time, while a solar eclipse is visible only along a narrow path on the earth's surface.
The Chaldaeans (fl. 1000 B.C. - 540 B.C.) discovered that eclipses of the sun recur in cycles of 18 years, 11 1/3 days; this cycle, called the saros, is an interval in which the sun, earth, and moon return to nearly identical relative positions. Since the orbits of the earth and moon are quite accurately known, eclipses can be predicted far in advance, both in time and location. Similar calculations can determine the time and place of past eclipses; this information is useful for dating historical events that are known to have occurred at the same time as an eclipse.
Tue 3 Mar 2009, 13:44 PM | Posted by admin
Tags: Science
Milk is the only natural food which contains almost all the essential constituents needed for our body. It is a mixture of water, fat, protein, sugar and inorganic salts. Cow is the chief source of milk in the world but in some countries it is also obtained from buffalo, sheep, goat, reindeer or camel. About half the amount of milk consumed in India is obtained from buffalo.
When a little amount of curd is added to milk whole of it gets converted into curd within 4 hours in summer and 12 hours in winter.
Do you know how milk gets converted into curd?
Milk contains a protein called casein. This protein gives milk its characteristic white colour. It is of high nutritional value because it contains all the essential amino acids required by man's body. The curd forms because of the chemical reaction between lactic acid bacteria and casein. When curd is added to milk, the lactic acid bacteria present in it cause coagulation of casein and thus convert it into curd.
Man has been using curd for a long time. It is very useful for stomach ailments. It keeps the d igestive system in good order. In the ancient times curd was sold as a medicine. Curd bacteria clean the intestinal system. According to some experts the regular consumption of curd keeps the stomach free from ailments. Curd is used in differjent ways by different people. Some use it with a little of salt while others use it with sugar. In Bengal, sugar is added to milk before converting it into curd. This is sold as sweet curd and called as "Shri Khand" in Madhya Pradesh.
Tue 3 Mar 2009, 13:41 PM | Posted by admin
Tags: Science
Coal, a commonly used fuel, is obtained from the coal mines. These mines are many miles wide and the coal is found in thick, flat layers. The thickness of these layers varies from a few centimetres to a few metres. Thousands of labourers and engineers equipped with machines work in these mines round-the-clock.
Do you know how the coal was formed?
Coal formation first began some 250 million years ago in an age called 'carboniferous period'. During that period our earth had many swamps. Fast growing plants and giant tree ferns grew in them. In time they died and fell into the quiet swamp water. They did not completely rot away because enough air was not available there. Bacteria changed the tree parts into a slimy material called peat. Over the centuries, this peat was compressed by mud and sand. The peat-beds were first turned into lignite by heat and pressure of the earth layers and finally into the hard coal. In this way coal was formed in many layers inside the earth. Today we have to dig to great depths to obtain it.
This theory about the coal-formation is based on the fact that fern's impressions are found within the coal. Sometimes patterns of bark are also seen on it, which again proves that it is formed from the remains of trees, plants and shrubs millions of years ago.
Coal mining is a very difficult job. First of all, the dirt above the coal deposit is removed. When the coal is exposed, explosives are used to break it into smaller pieces. Practically all of it has to be mined through machines and explosives. The coal thus removed is loaded into a wagon and lifted to the surface. The miners enter and leave the mine by an elevator through a vertical space called shaft. Coal mines catch fire easily. When a mine catches fire it is very difficult to extinguish it. Hence that portion of the mine is isolated from the rest to prevent the fire from spreading.
In our country coal mines exist in Andhra Pradesh, Bihar, West Bengal, Rajasthan, Maharashtra, Orissa, Assam, Jarnmu, Madhya Pradesh, etc. About three billion tons of coal is mined every year in the whole world. In India only about 100 million tonnes of coal is mined every year.
Tue 3 Mar 2009, 12:49 PM | Posted by admin
Tags: Science
A black hole is a celestial body whose surface gravity is so strong that no light can escape from within it.
Black hole gained popularity in the later 20th century. The concept of black hole goes back to the French mathematician Pierre Simon de Laplace. In year 1798, Laplace agreed with the theory of Isaac Newton that light is composed of particles. He reasoned that if enough mass were added to a star like the Sun, its gravitational force eventually would keep light particles from leaving its surface, and the star would become invisible. Almost a century later, Albert Einstein, in his special theory of relativity, defined that nothing can move faster than light. This means that Laplace's black stars are the black holes, because light and all other matter get trapped there. The surface of a black hole thus acts like a one-way membrane: material may fall into a black hole, but nothing can come out of it.
A German astrophysicist, Karl Schwarzschild, predicted the existence of black holes in 1917. He theoretically proved that black holes are the end result of all stars whose mass is much greater than the sun. Its size remains normal due to the balance between the two forces – one being the expansion force caused by the enormously high temperature which tends to expand the star’s material and that the other being enormously high temperature which tends to contract the star’s substance.
At one stage the lifetime of every star, its nuclear fuel decreases causing a fall in its core temperature. As a result, the gravitational pull takes over. Gradually the star begins to collapse. In this process the atoms present in the star break into electrons, protons and neutrons. The mutual repulsion between the electrons resists further contraction. The star, at this stage, is known as ‘White dwarf’. In this process the star is reduced to one hundredth part of its original size, thereby the gravitational pull in the white dwarf becomes about 10000 times more than the gravitational force of the original star.
After some time, under certain conditions, the gravitational pull becomes too strong to overcome electron repulsion. The star begins to contract further and in this process of contraction, electrons and protons combine together to form neutrons. The star at this stage is called Neutron star. Its size is now reduced to five-hundredth part of the dwarf star and the gravitational attraction becomes about 100,000,000,00 times of the original star.
The light emitted from the neutron star reduces its energy and as a result its size further decreases. At some stage, no radiation’s come out from this star. It is then called a black hole. These holes have such intense gravitational field that anything approaching it is trapped by it. It can never get out again.
Scientists are still looking for evidence of the actual existence of black holes in the universe. They have detected emissions of X-rays and infrared radiation’s in the areas tentatively marked as black holes.
More Considerations :
Black holes could be of different sizes. Stephen Hawking (English physicist) has surmise that tiny black holes with masses as large as mountains are possible . Such black holes, would have formed only under the extreme conditions that cosmology theories state, existed in the very first moments of the universe. On the other hand, gigantic black holes, may lie at the center of galaxies. Some astronomers suggest that these galactic-core black holes may be linked to the differences that exist among galaxies, which range from normal ones such as our Milky Way to the highly active galaxies called radio galaxies and quasars. The galaxies commonly have magnetic fields, which cannot be explained as being the sum total of the magnetic fields of a galaxy's individual objects. An attempts to calculate theoretically the magnetic fields of galactic have faced many problems, and a number of theorists suggest that the existence of huge black holes at galactic cores would give some help in this direction.
Laws of physics suggest that black holes would emit particles and shrink with time. According to Hawking, their temperatures would rise as they shrank, and they might finally evaporate with an enormous burst of energy. Finally, a popular misconception is that black holes would act like cosmic vacuum cleaners, sucking up everything within reach. In fact their gravitational attraction would be no stronger than that of a normal star of the same mass.
Tue 3 Mar 2009, 12:46 PM | Posted by admin
Tags: Science
Once the alphabet ha been invented, man could write; but what was he to write on? He needed to find something on which information could be preserved indefinitely, something stable and durable, something easy to handle which was at the same time fairly tough but not too difficult to tear, and as light as possible so that it could be easily transported. Smooth rock surfaces were the first 'paper' used by mankind. Remember that prehistoric men drew and painted on the stone walls of their caves. Inscription on stone were very short, exhausting for their author and had the enormous disadvantage of being impossible to move. The same difficulty applies to tree trunks, which are used by some primitive peoples to this date. Before the arrival of paper as we know it a whole series of writing surfaces were invented using materials such as clay tablets, papyrus, waxed tablets and parchment.
Today paper is one of the mainsprings of our civilization. It is said that the standard of living of a country can be measured by the amount of paper it consumes. Without paper there would be no books, no magazines, no newspapers, no notebooks . . . and so on. Thanks to paper, man has at his disposal one of the most convenient methods of communication. There can be no doubt that the invention of paper was one of the most important events in the history of humanity. The Babylonians invented tablets made of clay or mud on which they wrote with a stylus. The tablets were then baked.
The ancient Egyptians used papyrus, a substance derived from the plant of the same name, which has a triangular stem enveloped membrane which may be as much as 1m in length.
The Greeks and Romans had a different method of writing. They took notes on waxed tablets by mean of a pointed instrument which pierced the layer of wax. About 300 BC a war broke out between the kingdoms of Pergamum and Egypt. Eumenes, monarch of Pergamum, ordered his subjects to find a material which could replace Egyptian papyrus. The learned man of the kingdom discovered a substance made from sheep skin. The wool was removed and the hide was scraped, beaten and stretched. It became known as 'parchment', derived from the name of the country. In the Middle Ages the Arabs made known throughout Muslim Spain a material which was to replace all its predecessors. This was paper, whose manufacture they imported from far distant and mysterious realm of China.
The first paper appeared in China about 200 BC. Its name is derived from papyrus. Silk was transformed into paper by a process of pasting, but because silk was expensive, wool and cotton came to be used instead. This invention was attributed to Ts'ai Lun.
In the picture above, the manufacturing process used by the Chinese. They steeped mulberry or bamboo bark in water, then kneaded it to produce a paste from which they obtained smooth thin sheets of paper.
Tue 3 Mar 2009, 12:32 PM | Posted by admin
Tags: Science
The invention of zero has had a tremendous impact on the history of mankind because it made the development of higher mathematics possible. Although it is not known with certainty who invented it, yet there is no controversy about the claim that it was invented in India around landlord century A.D.
Right from the beginning of the civilization man has tried many different methods to write the numbers. For this purpose, Greeks used letters of their alphabet and Egyptians appropriate pictures. Romans used a complicated system. They used X to represent 10; 'C' to mark 100 and M for 1000. For one they used I, for 5 - 'V', for 50 - 'L,' for 500 - 'D'. They represented 4 by 'IV'. If they had to write 1648, they wrote 'M13CXLVIll'. This was indeed a complicated method.
However, long before the birth of Christ, the Hindus in India had invented a far better number system but without zero at that time. Later zero was invented. It was brought to Europe about the year 900 A.D. by the Arab traders and is called the Hindu-Arabic system.
In this system, all numbers are written within the nine digits 1, 2, 3, 4, 5, 6, 7, 8, 9 and the zero '0' (sunya). Here each figure has a value according to the place in which it is written. The Romans didn't have a zero in their system.
Zero has some peculiar properties. When it is added to or subtracted from any number, the result remains the same. When any number is multiplied by zero it becomes zero. It is the only number which can be divided by another number but it cannot divide any other number.
The expression 0/0 is neither meaningless nor meaningful. In fact, it is indeterminate. Zero is similar to all other natural numbers.
The invention of zero became the turning point in the development of culture and civilization - without which the progress of modern science, industry and commerce was inconceivable.
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