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PAN-India Science and Technology missions – 12th FYP Introduction
The role of Science, Technology and innovation has gained high significance in recent times in economic development processes of countries. Science departments, agencies and institutions, while supporting discovery science are also engaged in applications of science for development of technologies. It is becoming increasingly evident that design of solutions to national challenges like food and nutrition security, energy and environment security, affordable health care and water security would call for large nationally coordinated mission mode programmes involving inter-departmental and inter-ministerial collaborations. Approach paper for the 12th plan programmes called for launching PAN-India S&T missions in four such areas.
National Mission on Affordable Health Care
India’s success story of economic growth is in striking contrast to its increasingly crumbling public health infrastructure. While there are continuous efforts towards increasing investments in science and technology to help India to become a major S&T super power (like putting a man in moon by 2015), there is an unmet research and development need for delivering affordable health care to nearly 70% of Indian public.
India has a huge burden of patients with tuberculosis, malaria, HIV/AIDS, viral infections as the Japanese encephalitis, dengue. What is more, there are emerging and re emerging infections like swine flue. Even for many of the disease prevalent for decades like TB, malaria etc., diagnostics, drugs and vaccines are either decade old or inadequate.
Drug price control regimes, anti-competitive measures, and flexibilities in global IP regimes for the countries like India can help in a limited way but in the long run strong innovation-driven R&D directed to our needs is imperative to achieve the goal of affordable health care.
The sub-missions proposed are as follows:
Diabetes
The countries with the largest number of people with diabetes are, and will be in the year 2025, India, China, and the U.S. In developing countries, the majority of people with diabetes are in the age range of 45-64 years. Increasing incidence of diabetes in young adults of 20yrs and up is another area of concern. Low cost technologies, Islet Cell Transplantation, Gestational Diabetes, Prospective cohorts, Gene environmental interaction for Diabetes are the areas of Research under consideration
Medical instrumentation and Diagnostic tools
Given the software prowess that we have now, it only makes sense to target this area as an S& T mission and define a goal for certain areas of medical instrumentation and diagnostic tools to be completely designed and manufactured in
India. There is every possibility that by doing so, we can bring the healthcare costs down and make much of medical care affordable to our masses.
Innovative Health Care Delivery systems
In a country where the ratio of physicians per 1000 population is as low as those in poor economies, innovations are required for leveraging the relatively poor ratio of physicians per 1000 population is as low as those in poor economies, innovations are required for leveraging the relatively poor ratio of physicians per 1000 population by resorting to technology assisted methods –Electronic Health Records, Decision support software and Use of mobile phones for health care
Biomaterials for health care
Virtually all types of material systems have been used in health care applications, including metals and alloys, ceramics, polymers, composites, and biologically derived
biomaterials.
Developing materials that can be implanted in the body and remain for many years without adverse effects requires understanding of the biological processes that occur around the material and reactions that may occur once implanted in the body, especially if they can have harmful consequences. Recent developments in materials chemistry have led to 13significant improvements in drug delivery systems. Biocompatible
polymeric materials have been developed that allow for the controlled delivery of drugs, proteins and genes.
Research programs in development of biomaterials for body implants, Biomaterials for separation technologies used in medicine, Improved drug delivery systems, Development of medical sensors and Study of interaction between biomaterial and human body are the areas of research under which funds are allocated
Affordable health care diagnostic kits
Simple, quick and affordable diagnostic kits which can be used by Primary Health Centres, without extensive training, are not available in the market. Hospitals are not adequate to treat even the most common and regular outbreaks of Cholera, Typhoid, Dengue, chikungunya, JE besides several others.
To improve the healthcare, especially in a developing country like ours with limited resources, we need to focus on the development of simple, cost effective and rapid diagnostic kits.
Open Source Drug Discovery model of CSIR.
Some agencies like DST and DBT could take the lead and develop in consultation with ICMR and Ministry of Health suitable packages and programmes for developing Human capacity for R&D on mission mode in partnership with private sector.
Continue reading PAN-India Science and Technology missions – 12th FYP
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August 20th, 2013 | Tags: 12th FYP, science and technology Missions, science in india, technology | Category: Sci & Tech | 3 comments
Blue Green Algae
Contributed by Sai Krishnam Naidu
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Blue-green algae, more commonly known as cyanobacteria, is one of the simplest, most common, and earliest-appearing life forms on the planet. Cyanobacteria also known as blue-green bacteria or blue-green algae, is a phylum of bacteria that obtain their energy through photosynthesis. It can be found in almost every terrestrial and aquatic habitat.
Unlike other forms of “algae” like green, red, and brown algae, blue-green algae consists of bacteria –not eukaryotic cells. Bacterial cells are about ten times smaller than eukaryotic cells and lack nuclei and complex organelles (cellular
organs).
When blue-green algae first appeared on the scene about 2.8 billion years ago, it set in motion biochemical and atmospheric changes that eventually made it possible for complex life to exist. At the time blue-green algae evolved, the Earth’s atmosphere was composed mostly of nitrogen (like today), but the other gas, making up about 25%, was carbon dioxide. Blue-green algae was the first life forms capable of oxygenic photosynthesis, which takes in carbon dioxide and the Sun’s rays to produce energy, oxygen, and water.
After working for about 500 million years, the blue-green algae transformed the atmospheric carbon dioxide into mostly oxygen. This made much for free energy available for any subsequent organisms, but killed off all the anaerobic bacteria that had dominated the planet before. Because of the massive die-off, this event is known as the Oxygen Catastrophe.
Evidence of this event is left behind in the form of banded iron formations, rocks consisting of bands of oxidized iron compounds alternating with iron-poor minerals such as shale. These iron compounds formed when cyanobacteria were locking up iron in compounds which then sunk to the sea floor.
Cyanobacteria at mainly found in the oceans, where they are primary producers and are eaten by many other organisms. The blue-green tinge they give the water is the source of their name, blue-green algae. The green color comes from chlorophyll in their cells. In the oceans, where there is ample nitrogen available in seawater and carbon dioxide available from the atmosphere, the main limiting factor in their growth is iron. Some scientists have begun to experiment with fertilizing the oceans with iron to boost their
growth, which can sequester carbon dioxide from the atmosphere and curb global warming. You can read more about Iron Fertilization here
Cyanobacteria are also well-known for their ability to fix nitrogen — or convert it from gas form into solid form — another essential feature of any ecosystem. Other organisms convert fixed nitrogen compounds into protein and nucleic acids.
Some cyanobacteria are sold as food and may possess the ability to produce substances that could one day serve as anti-inflammatory agents and combat bacterial infections in humans. Recent research has suggested the potential application of cyanobacteria to the generation of renewable energy via converting sunlight into electricity. Currently efforts are underway to commercialize algae-based fuelssuch as diesel, gasoline and jet fuel.
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April 19th, 2013 | Tags: algae, biotechnology, carbon sequestration, science | Category: Sci & Tech | 2 comments
Dark Energy and Dark Matter IntroductionIn the early 1990′s, one thing was fairly certain about the expansion of the Universe. It might have enough energy density to stop its expansion and recollapse, or it might have so little energy density that it would never stop expanding, but gravity was certain to slow the expansion as time went on.
The Universe is full of matter and the attractive force of gravity pulls all matter together. Then came 1998 and the Hubble Space Telescope (HST) observations of very distant supernovae that showed that, a long time ago, the Universe was actually expanding more slowly than it is today. So the expansion of the Universe has not been slowing due to gravity, as everyone thought, instead it has been accelerating.
Source: Nasa
Eventually theorists came up with dark energy.
What Is Dark Energy?In physical cosmology and astronomy, dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe. Dark energy is the most accepted hypothesis to explain observations since the 1990s that indicate that the universe is expanding at an accelerating rate.
Many things about the nature of dark energy remain matters of speculation. The evidence for dark energy is indirect. However, it comes from three independent sources.
These are
Distance measurements and their relation toredshift, which suggest the universe has expanded more in the last half of its life.
The theoretical need for a type of additional energy that is not matter or dark matter to form our observationally flat universe (absence of any detectable global curvature), and
It can be inferred from measures of large scale wave-patterns of mass density in the universe.
Recent observations of supernovae are consistent with a universe made up 71.3% of dark energy and 27.4% of a combination of dark matter and baryonic matter
Dark energy is thought to be very homogeneous, not very dense and is not known to interact through any of the fundamental forces other than gravity.
Cosmologists estimate that the acceleration began roughly 5 billion years ago. Before that, it is thought that the expansion was decelerating, due to the attractive influence of dark matter and baryons. The density of dark matter in an expanding universe decreases more quickly than dark energy, and eventually the dark energy dominates. Specifically, when the volume of the universe doubles, the density of dark matter is halved
but the density of dark energy is nearly unchanged (it is exactly constant in the case of a cosmological constant).
What Is Dark Matter?In astronomy and cosmology, dark matter is a type of matter hypothesized to account for a large part of the total mass in the universe. Dark matter cannot be seen directly with telescopes; evidently it neither emits nor absorbs light or other electromagnetic radiation at any significant level.
Dark matter came to the attention of astrophysicists due to discrepancies between the mass of large astronomical objects determined from their gravitational effects, and the mass calculated from the “luminous matter” they contain: stars, gas and dust. On 3 April 2013, NASA scientists reported that hints of dark matter may have been detected by the Alpha Magnetic Spectrometer on the International Space
Station.
We are much more certain what dark matter is not than we are what it is. First, it is dark, meaning that it is not in the form of stars and planets that we see. Second, it is not in the form of dark clouds of normal matter, matter made up of particles called baryons. We know this because we would be able to detectbaryonic clouds by their absorption of radiation passing through them. Third, dark matter is not antimatter, because we do not see the unique gamma rays that are produced when antimatter annihilates with matter.
Because of the names, it’s easy to confuse dark matter and dark energy. And while they may be related, their effects are quite different. In brief, dark matter attracts, dark energy repels. While dark matter pulls matter inward, dark energy pushes it outward. Also, while dark energy shows itself only on the largest cosmic scale, dark matter exerts its influence on individual galaxies as well as the universe at large.
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April 17th, 2013 | Tags: alpha magneto spectrometer, NASA, science, space research | Category: Sci & Tech | Leave a comment
Wireless Communication Technologies Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor.
The most common wireless technologies use electromagnetic wireless telecommunications, such as radio. With radio waves distances can be short, such as a few metres for television remote control, or as far as thousands or even millions of kilometres for deep-space radio communications.
Though radio waves have lesser range of frequency spectrum, it is preferred over the shorter waves like UV or visible spectrum for following reasons:
1. For larger distances, the higher the frequency is, the faster the signal becomes attenuated and the weaker it becomes. So, radio waves that have wavelengths of some 10 km to 100 km or more (frequency ~3KHz to 30KHz) can be used for long distances like neighboring states/towns and higher/lower frequency for short/long distances. For visible spectrum (~500 Tera Hz), transmitting over great distances is a problem without guided media (like optic cables).
2. Some people are working in visible light communication but that technology has not yet become commercially viable for outdoor distances yet.
3. UV or Visible spectrum can cause heating/ ionizing effects and can create some problems with beings.
4. Ionosphere cannot reflect UV or visible rays because their frequency is too high.
Near field communication (NFC)
Near field communication (NFC) is a set of standards for smartphones and similar devices to establish radio communication with each other by touching them together or bringing them into close proximity, usually no more than a few centimeters Present and
anticipated applications include contactless transactions, data exchange, and simplified setup of more complex communications such as Wi-Fi.
NFC offers a low-speed connection with extremely simple setup, and can be used to bootstrap more capable wireless connections like Bluetooth. NFC and Bluetooth are both short-range communication technologies that are integrated into mobile phones. As described in technical detail above, NFC operates at slower speeds than Bluetooth, but consumes far less power and doesn’t require pairing.
NFC can be used in social networking situations, such as sharing contacts, photos, videos or files and entering multiplayer mobile games. Most importantly, The Pay-Buy-Mobile initiative seeks to define a common global approach to using Near Field Communications (NFC) technology to link mobile devices with payment and contact less systems.
Bluetooth
Bluetooth is a standard wire-replacement communications protocol primarily designed for low power consumption, with a short range based on low-cost transceiver microchips in each device. Because the devices use a radio (broadcast) communications system, they do not have to be in visual line of sight of each other, however a quasi-optical wireless path must be viable. It can connect several devices, overcoming problems of synchronization.
Bluetooth and Wi-Fi have some similar applications: setting up networks, printing, or transferring files. Wi-Fi is intended as a replacement for cabling for general local area network access in work areas. This category of applications is sometimes called wireless local area networks (WLAN). Bluetooth was intended for portable equipment and its applications. Wi-Fi uses the same radio frequencies as Bluetooth, but with higher power, resulting in higher bit rates and better range from the base station.
WiFi
A wireless network uses radio waves, just like cell phones, televisions and radios do. In fact, communication across a wireless network is a lot like two-way radio communication.
A computer’s wireless adapter translates data into a radio signal and transmits it using an antenna.
A wireless router receives the signal and decodes it. The router sends the information to the Internet using a physical, wired Ethernet connection.
The process also works in reverse, with the router receiving information from the Internet, translating it into a radio signal and sending it to the computer’s wireless adapter.
They transmit at frequencies of 2.4 GHz or 5 GHz. This frequency is considerably higher than the frequencies used for cell phones, walkie-talkies and televisions. The higher frequency allows the signal to carry more data.
LiFi
Li-Fi is the term some have used to label the fast and cheap wireless-communication system, which is the optical version of Wi-Fi. Li-Fi has the advantage of being able to be used in sensitive areas such as in aircraft without causing interference. However, the light waves used cannot penetrate walls. Also transmitting in visible light spectrum offers a wide range of frequencies however line of sight is necessary here.
RFID
RFID stands for Radio-Frequency Identification. The acronym refers to small electronic devices that consist of a small chip and an antenna. The RFID device serves the same purpose as a bar code or a magnetic strip on the back of a credit card or ATM card; it provides a unique identifier for that object. And, just as a bar code or magnetic strip must be scanned to get the information, the RFID device must be scanned to retrieve the identifying information.
A significant advantage of RFID devices over the others mentioned above is that the RFID device does not need to be positioned precisely relative to the scanner.
Some common problems with RFID are reader collision and tag collision. Reader collision occurs when the signals from two or more readers overlap. The tag is unable to respond to simultaneous queries. Systems must be carefully set up to avoid this problem. Tag collision occurs when many tags are present in a small area; but since the read time is very fast, it can be avoided easily.
Barcode
A barcode is designed to eliminate manual entry and error. It is simply a series of stripes (usually black) on a light background (usually white) that can be scanned and read directly into a computer. They are interpreted virtually instantaneously and without errors by a bar code reading system. The elements (bars and spaces) in a bar code symbol must be of a consistent, proportional thickness and
thinness.
Bar codes are read the same way that people read text from a page; the reflectance and absorption of light. A light of a given wavelength is beamed and moved across a bar code at a consistent speed. The reflected light is measured with a photoreceptor, tuned to look for light of the given wavelength. The off-and-on (white and black) pattern of the bar code creates an electrical wave that is sent on to a computer chip called a “decoder.” The decoder then deciphers the signal into something the waiting computer understands.
The main advantage is it is simple and very economical to use. Disadvantage is that the bar code is to be read in line of sight unlike the RFID technology.
QR Codes
QR Code is a very efficient, two-dimensional (2D) barcode symbology that uses a small area of square modules with a unique perimeter pattern, which helps the barcode scanner determine cell locations and decode the QR Code symbol. Characters, numbers, text and actual bytes of data may be encoded, including Unicode characters and images.
QR Code
QR Codes are commonly used with smart-phone devices such as the iPhone, Blackberry, Android and Windows 7 Phones to direct users to additional information about a particular topic like website url, image, social media hubs, email addresses etc. QR Codes are some of the smallest and most dependable barcodes in use today. The QR Code symbology is approximately 30 times smaller than a barcode representing the same data. QR Code is also a good choice when sending barcodes over faxed documents, because the symbol can withstand many poor resolution and scanning issues.
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April 16th, 2013 | Tags: bluetooth, lifi, near field communication, radio communication, technology, wifi | Category: Sci & Tech | Leave a comment
Cloud Seeding Cloud seeding in briefCloud Seeding is the mechanism of spreading silver iodide aerosols or more commonly dry ice in the upper portion of the clouds to initiate the precipitation process and form rains. Spreading of silver iodide particles augment the growth of ice particles which result in the formation of rainfall. Seeding normally is performed only on those clouds which show positive results when it comes to the potential of producing rains.
The most common chemicals used for cloud seeding include silver iodide and dry ice (solid carbon dioxide). Liquid propane, which expands into a gas, has also been used. This can produce ice crystals at higher temperatures than silver iodide. Cloud
seeding chemicals may be dispersed by aircraft or by dispersion devices located on the ground.
Cloud Seeding Experiments in AsiaThe largest cloud seeding system in the world is that of thePeople’s Republic of China, which believes that it increases the amount of rain over several increasingly arid regions, including its capital city, Beijing, by firing silver iodide rockets into the sky where rain is desired.
In India, cloud seeding operations were conducted during the years by Tamil Nadu Government due to severe drought. In the later years Karnataka government and Maharashtra initiated cloud seeding.Recently Maharashtra government is planning to adopt cloud seeding technology, to combat ongoing drought if the monsoon arrives late.
Rainfall processNatural rainfall occurs when super cooled cold water contacts particles of dust, salt or sand forming ice crystals. The ice crystals provide a nucleus (tiny solid or liquid particles, suspended in the atmosphere) around which more water droplets can attach, increasing the size of the droplet, or in colder air snowflakes. When the droplet or snow flake, becomes large enough, it falls as snow or rain. This is the cold rain process.
Another process, the warm rain process, usually involves clouds in tropical regions that never reach the freezing point. In these clouds, raindrops form around a hygroscopic nuclei, a particle that attracts water such as salt or dust. Small droplets collide and coalesce until they form a drop large and heavy enough to fall.
Types of Cloud SeedingThere are three cloud seeding methods: static, dynamic and hygroscopic.
Static cloud seeding: In mid-latitude clouds, the usual seeding strategy has been based on the fact that the equilibrium vapour pressure is lower over ice than over water. The formation of ice particles in super cooled clouds allows those particles to grow at the expense of liquid droplets. If sufficient growth takes place, the particles become heavy enough to fall as precipitation from clouds that otherwise would produce no precipitation. This process is known as “static” seeding. It involves spreading a chemical like silver iodide into clouds. To sum up, static seeding aids cold raining process
Dynamic cloud seeding aims to boost vertical air currents, which encourages more water to pass through the clouds, translating into more rain. Seeding of warm-season or tropical cumulonimbus (convective) clouds seeks to exploit the latent heat released by freezing.
Hygroscopic cloud seeding disperses salts through flares or explosives in the lower portions of clouds. The salts grow in size as water joins with them.
Criticism Firstly this process is too expensive and validity is questioned. Secondly, silver iodide is found to cause temporary incapacitation or possible
residual injury to humans and mammals There is also criticism that increasing rain in one area neutralizes with the
decreased rain in the other which is becoming the reason of disputes between neighbouring states.
However those favouring the process feel that the process has the potential to make up for the delay in monsoon and water loss at various parts of the world.
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April 5th, 2013 | Tags: artificial rain, technology | Category: Sci & Tech | Leave a comment
Rare Earth Metals What are Rare Earths?Rare earths are a group of 17 metallic elements, specifically the fifteen lanthanides plus scandium and yttrium with very unique properties that are widely used in energy and
lighting technologies. Their oxides are used in products such as hard drives, fuel cells, wind turbines, polishing powders and catalytic converters.
The extent to which REM’s are used in defense technology is such that without their production modern warfare—fighter jets, drones, and most computer-controlled equipment—would have to undertake a lengthy process of redevelopment.
Why the name Rare Earths?The name, rare earth metal, is a misnomer. The metals are, in fact, far more abundant than many precious minerals. Yet their dispersion means they are rarely found in economically viable quantities.
Why are costs of Rare Earths so rapidly changing?A variety of factors continue to inflate the cost of these materials as realization of their intrinsic value increases. Rare earth elements are not exchange-traded in the same way that precious (for instance, gold and silver) or non-ferrous metals (such as nickel, tin, copper, and aluminium) are. Instead they are sold on the private market, which makes their prices difficult to monitor and track. Demand for rare earths continues to grow in line with growth in green technologies. Supply, however, is declining as China, the main producer of rare earths, imposes quotas on its rare earth exports every year. Demand for some rare earths will outpace supply for some time.
What does Rare Earth Metals mean for India?
REMs are becoming a strategic resource over which the two emerging giants are competing in Asia. Indeed, one might say rare earths are fast becoming “the next oil.”
China accounts for about 95% of the global output of rare-earth minerals, which are used in a range of electronic equipment. At a time when the world’s largest producer, China, has tightened its own exports of the minerals, India has embarked on an ambitious plan to increase its output of rare-earth minerals used in electronics manufacturing.
Rare earth deposits in India are of two major types: endogenic and exogenic. The Endogenic types include some carbonatites, metamorphic rocks, the Exogenic types comprise coastal or beach placers etc. The endogenic deposits do not appear to be very much attractive from exploitational point of view. Mainly beach placers are mined in India at present. Monazite is the principal ore mineral for REE in India. India has set itself the target of having a monazite processing plant with a capacity of 10,000 tonnes.
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April 3rd, 2013 | Tags: minerals, mining, rare earths | Category: Sci & Tech | Leave a comment
Autism IntroductionAutism is a disorder of neural development characterized by impaired social interaction and communication, and by restricted and repetitive behavior. It is a ‘spectrum disorder,’ because the severity of symptoms ranges from a mild learning and social disability to a severe impairment, with multiple problems and highly unusual behavior. The condition is the result of a neurological disorder that has an effect on normal brain function, affecting development of the person’s communication and social interaction skills.
DiagnosisAutism is not a rare disorder, being the third most common developmental disorder, more common than Down’s Syndrome. Autism affects as many as 1 in 110 children and 1 in 70 boys. Boys are four times more likely than girls to have autism. There are 8 million persons with autism and other development disorders in India.
Diagnosis is based on behavior, not cause or mechanism. The diagnostic criteria require that symptoms become apparent before a child is three years old.
Autism – GeneticsAutism has a strong genetic basis, although the genetics of autism are complex and it is unclearwhether ASD is explained more by rare mutations, or by rare combinations of common genetic variants. Complexity arises due to interactions among multiple genes, the environment; hence heritable and influence gene expression.
Treatment/ CureAt present, there is no cure for autism: there is no medication, no pills, no injections which can make the problem go away. The only consistently effective treatment for
autism is a structured training program; therefore, a combination of a good school and parent training is the best known treatment. The main goals when treating children with autism are to lessen associated deficits and family distress, and to increase quality of life and functional independence. No single treatment is best and treatment is typically tailored to the child’s needs.
How is Autism different from Mental Retardation?When a person has M.R. there is a more or less even impairment in skills in all areas of development. Therefore, if an M.R. child of 8 years has a mental age of 5 then all his skills would be roughly around 5 years (i.e. motor, communication, social, self-help, cognition etc.). In Autism, there is an uneven skill development- in fact this is the hallmark of autism. In some areas the child may show age-appropriate skills; in some the skills may be below the developmental level; and then again there are people with Autism who possess exceptional skills i.e. beyond their age level.
Autism – Indian Government.In India efforts are made to provide education to the autistic children upto the elementary level with appropriate support. Under the Sarva Shiksha Abhiyan (SSA) steps have been taken to provide education to the autistic children.
As per the Section 3 of the Right to Education (RTE) Act, every child of the age of six to fourteen years shall have the right to free and compulsory education in a neighbourhood school till completion of elementary education. SSA has adopted a zero rejection policy wherein efforts are made to provide education to all children with special needs.
India recently hosted the first conference of South Asian Autism Network (SAAN) in this February which concluded with Delhi Declaration on Autism. SAAN was born to combat the devastating autism public health crises. The intention is to identify common challenges each country is facing and form a partnership to develop solutions in a collaborating and coordinated fashion.
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April 3rd, 2013 | Tags: mental disorder, persons with disabilities, science | Category: Sci & Tech | 4 comments
Light Bulbs Light BulbsLight is a form of energy which is produced by two processes – INCANDESCENCE and LUMINESCENCE. Incandescence is the emission of light by hot objects. Luminescence is the emission of light without using heat. In lamps, both processes use electric current but only luminescent lamps make use of mercury.
Below mentioned are some common types of bulbs:
Incandescent BulbsAn incandescent light bulb, incandescent lamp or incandescent light globe is an electric light which produces light with a filament wire heated to a high temperature by an electric current passing through it, until it glows. The hot filament is protected from oxidation with a glass bulb that is filled with inertgas (or evacuated) that reduces the evaporation of the tungsten filament and gives the bulb a longer lightening life.
Halogen
Bulbs Halogen bulbs are improved versions of normal incandescent bulbs.
A halogen lamp has a small amount of a halogen such asiodine or bromine added. The combination of the halogen gas and the tungsten filament produces a halogen cycle chemical reaction which redeposit evaporated tungsten back on the filament, increasing its life and maintaining the clarity of the envelope
Fluorescent BulbsFluorescent bulbs do not have a filament but they too like the incandescent bulbs glow when provided with electricity. A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapour. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful light much more efficiently than incandescent lamps.
Tube light used in homes is a fluorescent bulb. When the switch is pressed current cannot pass through the tube initially because the gas inside it is not ionized and hence the tube light circuit behaves as open circuit. Once the gas is ionized, it will provide a conduction path for the current to flow. In order to ionize the gas, an initial high current is required for a short period across the filaments of the main tube. That is what a starter does. A starter initially provides a path to complete the circuit and once tube light starts the current flows through the ionized gas in the main tube. Ballast or choke is intended to limit the amount of current in an electric circuit. CFL contains ballast internally.
They are efficient than incandescent bulbs but expensive. Also discharging these bulbs is one of the main concern due to presence of mercury in them.
Discharge bulbs Gas-discharge lamps are a family of artificial light sources that generate light by sending an electrical discharge through an ionized gas, a plasma. They consist of two electrodes, when an electric current is passed, an arc is formed between these two electrodes. The resulting arcis then responsible for producing light.
Either the arc is luminous itself or it may be illuminated due to a phosphor coating on the surface of the lamp. The arc is actually formed between the electrodes due to the gas present within the sealed bulb.
Common discharge bulbs are mercury and sodium discharge bulbs.
Light Emitting Diode bulbsThese bulbs too do not have a filament but they are different from the fluorescence bulbs as they are not packed with vapours. These are in fact semiconductors which glow when provided with electric potential.
LEDs are considered as the best option for various uses as their energy consumption is very low and they give a good, bright light. Also they have a longer life.
Sodium Vapour LampsA sodium-vapour lamp is a gas-discharge lamp that uses sodium in an excited state to produce light. There are two varieties of such lamps: low pressure and high pressure.
Low-pressure sodium (LPS) lamps have gas discharge tube (arc tube) containing solid sodium, a small amount of neon, and argon gas in a Penning mixture to start the gas discharge. These lamps produce a virtually monochromatic light. Low-pressure sodium lamps are the most efficient electrical light sources, but their yellow light restricts applications to outdoor lighting such as street lamps.
High-pressure sodium (HPS) lamps are smaller and contain additional elements such as mercury. High-pressure sodium lamps have a broader spectrum of light but poorer color rendering than other types.
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April 1st, 2013 | Tags: home light appliances, science | Category: Sci & Tech | Leave a comment
Rice Husk Power System In order to generate electricity, biomass can be combusted, gasified, biologically digested orfermented, or converted to liquid fuels for propelling generators. Rice husk is one such source of Biomass.
Properties of Rice Husk:
Has very low nutrient and takes longer time to decompose due to high silica content thereby not favouring to use as manure.
Nearly 25% used in poultry and in brick kilins, rest is burnt freely in air leading to GHG emmissions
Can be used as cementing materials as well as biofuel for gasification;
Principle:
Generation of power from rice husk is basically a process of biomass gasification leading to production of highly combustible gases consisting of Carbon monoxide (CO),Hydrogen (H2) and traces of Methane (CH4). This mixture is called Producer Gas.Producer Gas can be used to run internal combustion engines (both compression and spark ignition). In short, this Producer Gas is used to run modified diesel engines to generate electricity.
MNRE :
The Ministry of New and Renewable Energy (MNRE) is promoting rice husk based distributed / off grid electricity generation through biomass gasifier system for meeting unmet demand of electricity in rural areas.
Source: http://manipursfac.com/an-attractive-alternative-electricity-from-rice-husk/; Press Information Bureau
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March 23rd, 2013 | Tags: clean technology, renewable energy, technology | Category: Sci & Tech | Leave a comment
Touch Screen Technology A touchscreen is an electronic visual display that the user can control through simple or multi-touch gestures by touching the screen with one or more fingers
There are a variety of touchscreen technologies that have different methods of sensing touch.
Resistive SystemThe resistive system consists of a normal glass panel that is covered with a conductive and a resistive metallic layer. These two layers are held apart by spacers, and a scratch-resistant layer is placed on top of the whole setup. An electrical current runs through the two layers while the monitor is operational.
When a user touches the screen, the two layers make contact in that exact spot. The change in the electrical field is noted and the coordinates of the point of contact are calculated by the computer.
Resistive touch is used in restaurants, factories and hospitals due to its high resistance to liquids and contaminants. A major benefit of resistive touch technology is its low cost. Disadvantages include the need to press down, and a risk of damage by sharp objects. Resistive touchscreens also suffer from poorer contrast, due to having additional reflections from the extra layer of material placed over the screen.
Capacitive SystemIn the capacitive system, a layer that stores electrical charge is placed on the glass panel of the monitor. When a user touches the monitor with his or her finger, some of the charge is transferred to the user, so the charge on the capacitive layer decreases. This decrease is measured in circuits located at each corner of the monitor.
Unlike a resistive touchscreen, one cannot use a capacitive touchscreen through most types of electrically insulating material, such as gloves. This disadvantage especially affects usability in consumer electronics, such as touch tablet PCs and capacitive smartphones in cold weather. Advantages include good contrast.
The surface acoustic wave SystemOn the monitor of a surface acoustic wave system, two transducers (one receiving and one sending) are placed along the x and y axes of the monitor’s glass
plate. Also placed on the glass are reflectors — they reflect an electrical signal sent from one transducer to the other. The receiving transducer is able to tell if the wave has been disturbed by a touch event at any instant, and can locate it accordingly.
The surface acoustic wave setup is usually the most expensive. The wave setup has no metallic layers on the screen, allowing for 100% light throughout and perfect image clarity. This makes the surface acoustic wave system best for displaying detailed graphics