Sunday, 13 April 2014
Tuesday, 11 March 2014
What is 'black box' in Flights ?
After the disappearance of Malaysia Airlines Flight MH370 shortly after midnight on Saturday, investigators considering a range of possible causes - mechanical failure or pilot error - have yet to turn up solid clues. They don't even know where the plane disappeared, which means that for grieving families this misfortune will remain a mystery until the recovery of the plane's 'black box'.What is this 'black box'? It is actually a flight data recorder (FDR) or accident data recorder (ADR) is an electronic device employed to record any instructions sent to any electronic systems on an aircraft. It is a device used to record specific aircraft performance parameters. Another kind of flight recorder is the cockpit voice recorder (CVR), which records conversation in the cockpit, radio communications between the cockpit crew and others (including conversation with air traffic control personnel), as well as ambient sounds. In this both functions have been combined into a single unit. The term "black box" is popularly referred by the media. The data recorded by the FDR is used for accident investigation, as well as for analyzing air safety issues, material degradation and engine performance.
FDRs are usually located in the rear of the aircraft, typically in the tail. In this position, the entire front of the aircraft is expected to act as a "crush zone" to reduce the shock that reaches the recorder. Also, modern FDRs are typically double wrapped, in strong corrosion-resistant stainless steel or titanium, with high-temperature insulation inside. They are usually bright orange. They are designed to emit an underwater locator beacon for up to 30 days and can operate immersed to a depth of up to 6,000 meters (20,000 ft).
Monday, 10 March 2014
Do you know the chemistry behind airbags ?
Airbags in car as safety equipment inflates within one-twenty-fifth of a second! Have you ever wondered from where does this amount of gas comes in such short interval of time? Where is this gas stored? What makes airbag to inflate? Do the money spend on it really worth? In this article I will discuss the mechanism behind inflation of airbag and the chemistry behind its quick reaction.
The aim of an airbag is to slow the passenger's forward motion as evenly as possible in a fraction of a second. This increases survival chances of the passenger in automobile accidents. In my opinion airbags should be compulsory as car insurances. Slight addition in your car loan can be your invaluable expenditure. There are three parts to an airbag :
1. The bag itself is made of a thin, nylon fabric, which is folded into the steering wheel or dashboard or, more recently, the seat or door.
2. The sensor is the device that tells the bag to inflate. Inflation happens when there is a collision force equal to running into a brick wall at 10 to 15 miles per hour (16 to 24 km per hour). A mechanical switch is flipped when there is a mass shift that closes an electrical contact, telling the sensors that a crash has occurred. The sensors receive information from an accelerometer built into a microchip.
3. The airbag's inflation system reacts sodium azide (NaN3) with potassium nitrate (KNO3) to producenitrogen gas. Hot blasts of the nitrogen inflate the airbag.
Older airbag systems contained a mixture of sodium azide (NaN3), KNO3, and SiO2. A typical driver-side airbag contains approximately 50-80 g of NaN3, with the larger passenger-side airbag containing about 250 g. Within about 40 milliseconds of impact, all these components react in three separate reactions that produce nitrogen gas. The reaction involved is :
1. 2 NaN3 → 2 Na + 3 N2 (g)
2. 10 Na + 2 KNO3 → K2O + 5 Na2O + N2 (g)
3. K2O + Na2O + 2 SiO2 → K2O3Si + Na2O3Si (silicate glass)
The inflation system is not unlike a solid rocket booster (see How Rocket Engines Work for details). The airbag system ignites a solid propellant, which burns extremely rapidly to create a large volume of gas to inflate the bag. The bag then literally bursts from its storage site at up to 200 mph (322 kph) -- faster than the blink of an eye! A second later, the gas quickly dissipates through tiny holes in the bag, thusdeflating the bag so you can move.
Sunday, 9 March 2014
How Ultra-Ever Dry works ??
Its a hydrophobic coating. According to Ultra-tech, a Florida-based containment provider for chemical clean-up and waste management, its new Ultra-Ever Dry coating is an amazing product. The coating is "super-hydrophobic" and "oleophobic," meaning it repels almost any liquid on a wide range of materials, including – but not limited to – hammers to boots and gloves as you'll see in the following video demonstration.
The two part Ultra-Ever Dry system creates a near invisible barrier of air over surfaces on the nanoscale. These surfaces can range from refined oil, wet concrete, water, mud and other liquids. In industrial application Ultra-Dry could prove ideal for specific applications, like when you drop your hammer in mud, and then step in the mud in your boots, and reach into the mud with your work-gloves.
Water proofing products and barriers are not new but according to the manufacturer, Ultra-Ever Dry has improved adhesion and abrasion resistance compared to previous iterations. The supposed adhesion and abrasive resistance traits then allow for a more diverse range of uses. Other claims include anti-icing, anti-corrosive, anti-contamination and self-cleaning capabilities.
But according to the abrasion resistance notes Ultra-Ever Dry provides "more abrasion resistance than previous superhydrophobic materials." Registering a 110 on the Taber Abrasion Method (ASTM D4060-10) the manufacturer recommends testing of surfaces if abrasion is a concern.
The product can be applied with a spray gun and finishes up to a translucent white sheen. A single coating is reported to last anywhere from 2-8 months in direct sunlight and outdoor conditions before a top-coat re-coating is needed. Indoor and protected outdoor applications put longevity at approximately one year or more. From the underside of a Polar Bear to the backside of a New York taxi driver in August, Ultra-tech professes a working hot/cold range of -30°F to 300°F (-34°C to 149°C).
Can I use it on my SquareBob lunchbox? Maybe. In addition to the "do not breathe this" warning a rather toxic grocery list of chemicals makes up the ingredients, thus making the coating a less than ideal Peanut Butter & Jam option. However, according to Ultra-tech there are no known environmental concerns. The coating is stated to be safe for use in "nonfood" (i.e. not your lunchbox) contact areas of food processing plants and meets FDA and USDA regulations for those types of applications.
The Ultra-Ever Dry coating prices out at $53/quart (0.95 liters) for the bottom coating and $96/quart for the top.
Friday, 21 June 2013
Heliophysics
We live in the extended atmosphere of an active star. While sunlight enables and sustains life, the Sun's variability produces streams of high energy particles and radiation that can harm life or alter its evolution.
Under the protective shield of a magnetic field and atmosphere, the Earth is an island in the Universe where life has developed and flourished. The origins and fate of life on Earth are intimately connected to the way the Earth responds to the Sun's variations.
Understanding the Sun, Heliosphere, and Planetary Environments as a single connected system is the goal of the Science Mission Directorate's Heliophysics Research Program. In addition to solar processes, our domain of study includes the interaction of solar plasma and radiation with Earth, the other planets, and the Galaxy. By analyzing the connections between the Sun, solar wind, planetary space environments, and our place in the Galaxy, we are uncovering the fundamental physical processes that occur throughout the Universe. Understanding the connections between the Sun and its planets will allow us to predict the impacts of solar variability on humans, technological systems, and even the presence of life itself.
We have already discovered ways to peer into the internal workings of the Sun and understand how the Earth's magnetosphere responds to solar activity. Our challenge now is to explore the full system of complex interactions that characterize the relationship of the Sun with the solar system. Understanding these connections is especially critical as we contemplate our destiny in the third millennium. Heliophysics is needed to facilitate the accelerated expansion of human experience beyond the confines of our Earthly home. Recent advances in technology allow us, for the first time, to realistically contemplate voyages beyond the solar system.
There are three primary objectives that define the multi-decadal studies needed:
There are three primary objectives that define the multi-decadal studies needed:
A combination of interrelated elements is used to achieve these objectives. They include complementary missions of various sizes; timely development of enabling and enhancing technologies; and acquisition of knowledge through research, analysis, theory, and modeling.
Wednesday, 19 June 2013
PLANETS AROUND OTHER STARS
What are exoplanets?
Throughout recorded history and perhaps before, we have wondered about the possible existence of other worlds, like or unlike our own. The earliest understanding of the solar system showed us that there were indeed other worlds in orbit about our Sun, and steadily growing understanding of their natures shows that all are dramatically different from Earth, and mostly very different from one another. As we came to understand that the stars in the sky are other suns, and that the galaxies consist of billions of stars, it appeared a near certainty that other planets must orbit other stars. And yet, it could not be proven, until the early 1990’s. Then, radio and optical astronomers detected small changes in stellar emission which revealed the presence of first a few, and now many, planetary systems around other stars. We call these planets “exoplanets” to distinguish them from our own solar system neighbors.
How we know that there are planets around other stars?
Most of the detected exoplanets have revealed their presence by small effects that they have on their star. As planet follows its orbital path, the star follows a complementary motion of its own. This is a tiny effect proportional to the planet/star mass ratio – in the case of the solar system, the Sun moves in synch with the Earth at the speed of a slow dance – currently too slow to readily detect in a distant system. The motion of the Sun in synch with Jupiter, however, is closer to a fast run – and in favorable cases it can be detected by several methods. The motion of the host star can be measured as a shift in its spectrum (the Doppler shift) or as a change in its position on the sky (astrometry). In both cases these are very challenging measurements and require exquisitely sensitive instruments. Exoplanet orbits presumably have random orientations, and in some cases the orbit carries the planet between us and its star. Then the exoplanet might be detected by the decrease in the light from the star. Such transitshave been observed, and a number of planets discovered by this method.
Another effect that can reveal the presence of a planet around another star is the bending of light from background stars by the gravitational field of an intervening star. If the intervening star has an orbiting planet it may alter the gravitational lensing effect in a noticeable way (microlensing). The large majority of the several hundred known extrasolar planets have been discovered by the Doppler technique, and other methods are contributing more significantly as they are refined and the number of detected exoplanets continues to increase steadily.
Another effect that can reveal the presence of a planet around another star is the bending of light from background stars by the gravitational field of an intervening star. If the intervening star has an orbiting planet it may alter the gravitational lensing effect in a noticeable way (microlensing). The large majority of the several hundred known extrasolar planets have been discovered by the Doppler technique, and other methods are contributing more significantly as they are refined and the number of detected exoplanets continues to increase steadily.
What do we know about our exoplanet neighbors?
Although the details are not entirely understood, it is known that stars like the Sun form from spinning protostellar disks of gas and dust. The Earth and other planets of the solar system are believed to have developed from the remains of that disk, and there is no reason to believe that the same process would not be effective throughout the galaxy. Thus a first guess might be that other planetary systems would be like the solar system.
However, the first detections of exoplanets revealed bodies which are utterly unlike any solar system planet – and subsequent discoveries have shown that many exoplanet systems are very dissimilar from ours. In some exosystems, planets as massive as Jupiter orbit so close to their star that they are heated to high temperature and their upper atmospheres are swept into space. In other systems, planets follow elongated orbits (in contrast to the nearly circular orbits of the solar system). However, our studies of exoplanets are just beginning, and it is not possible to be sure what will prove to be “typical” planets among our neighboring stars. Will most planet systems prove to be much like our own, or are we exceptional in more ways than we can imagine? Only years of further study will tell.
Evidence is accumulating that exoplanet systems which resemble the solar system are being found. The star 55 Cancri, 41 light years away, has a system of 5 planets, with distributions somewhat similar to the solar systems inner planets (though with much higher masses). As our measurements become sensitive to lower masses, some astronomers believe that we will find many such systems with a substantial complement of planets (perhaps even dynamically full – that is, containing as many planets as can coexist in orbital harmony).
In other reports, a number of planets with masses near that of Earth have been detected. The results are few, but because the measurements are very difficult, the detections are considered significant and possibly indicative of many more to be found in the future. Again, only years of study will tell.
Evidence is accumulating that exoplanet systems which resemble the solar system are being found. The star 55 Cancri, 41 light years away, has a system of 5 planets, with distributions somewhat similar to the solar systems inner planets (though with much higher masses). As our measurements become sensitive to lower masses, some astronomers believe that we will find many such systems with a substantial complement of planets (perhaps even dynamically full – that is, containing as many planets as can coexist in orbital harmony).
In other reports, a number of planets with masses near that of Earth have been detected. The results are few, but because the measurements are very difficult, the detections are considered significant and possibly indicative of many more to be found in the future. Again, only years of study will tell.
What do we want to learn about exoplanets?
A thorough understanding of exoplanets will tell us much about how our solar system formed, why it has small, rocky planets near the Sun, why it has gas giant planets far from the Sun, why the Earth has the conditions and chemicals that can support life, and why conditions on other planets are hostile to life. Theories of planet formation and evolution are incomplete, but offer specific predictions. Detections of exoplanets are already testing, validating, and in some cases invalidating, details of these theories.
Perhaps the most interesting question, and one of the most difficult to answer, concerns the uniqueness of the Earth. Are there planets similar to the Earth around other stars and does life exist on any other planet beyond our own Earth?
Recent Discoveries
How did the universe originate and evolve to produce the galaxies, stars, and planets we see today?
How did we get here? In order to understand how the Universe has changed from its initial simple state following the Big Bang (only cooling elementary particles like protons and electrons) into the magnificent Universe we see as we look at the night sky, we must understand how stars, galaxies and planets are formed.
There are many questions associated with the creation and evolution of the major constituents of the cosmos. A basic question astronomers must address is, how did the Universe create its first stars and galaxies? Once these entities were created, how did they influence subsequent galaxy, star and planet formation? This is an important question, because these later objects are made of elements that can only have been created by the first generation of stars.
It is still unknown whether the Universe created black holes with the first generation of stars or whether these exotic objects were created by the first generation of stars. Because black holes represent the most extreme physical conditions of spacetime and generate some of the most energetic phenomena following the Big Bang, they are the ultimate physical laboratories for testing theories of the Universe.
We now know that our Universe has a "foamy" structure. The galaxies and clusters of galaxies that make up the visible Universe are concentrated in a complex scaffold that surrounds a network of enormous cosmic voids. However, in addition to the "normal" matter that makes up the visible parts of the Universe, scientists have discovered that there are vast amounts of unseen matter. This so-called, "dark matter" makes up roughly 23% of the matter-energy content of the Universe, while the visible pieces account for only about 5% of the total. Clearly, if we hope to understand the structure of the Universe and the processes by which it formed and evolves, we must first understand the distribution of this important but unseen dark matter and the ways in which it interacts with and influences normal matter.
Though astronomers have been studying stars for thousands of years, it is only in the past 35 or so years that they have been able to employ instruments that detect light across the entire electromagnetic spectrum–from radio waves to gamma rays–to peer into the dusty clouds where stars are born in our own Galaxy. If we are to comprehend how the Universe makes stars–and planets that orbit them today–we must continue these studies with ever more powerful telescopes.
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