Comet Ison

An End Foretold:

Like every great comet, C/2012 S1 — better known to the world as Comet ISON — is dying. You could say the story of its demise began 14 months ago, when two observers near Kislovodsk, Russia, stumbled across a dim, fuzzy object while they scanned the sky near the constellations Cancer and Gemini. That fuzz was the outer layers of Comet ISON disintegrating and dispersing as it accelerated toward the warmth of the sun.
You could push further back and trace the comet’s downfall to a fateful event a few million years earlier. At the time, it was an inert chunk of ice, dust and frozen gases, foating nearly motionless in the outermost region of the solar system, a thousand times more distant than Pluto. Then some unknown disturbance, perhaps the nudge of a passing star, dislodged the comet from its stasis and sent it on a self-destructive sunward plunge.
Or you could say that Comet ISON’s end was foretold 4.56 billion years ago, when it and trillions of others like it formed during the birth of the solar system. Some of those comets collided with the infant planets; on Earth, they helped build the atmosphere and fll the oceans. But some of the comets were fung outward into distant cold storage. In that sense, the sunward journey of Comet ISON is a homecoming after a long exile.
Regardless of when the story begins, we know exactly when it will reach its climax: at 1:41 p.m. EST on Nov. 28, 2013, when the ice-packed Comet ISON reaches perihelion — the point closest to the sun — passing less than 750,000 miles (1.2 million kilometers) above the solar surface. There, ISON will roast at more than 2,000 degrees Celsius (hotter than 3,600 degrees Fahrenheit), boiling off layer after layer of its frozen surface. In the process, it will offer a frsthand look at the raw material that Earth and the other planets were built from when the solar system was formed.
Maybe some diminished portion of the comet will remain intact; maybe it will break apart and disperse entirely. Either way, the public unraveling of Comet ISON will be cause for celebration, not mourning. “Comet ISON is an extra- ordinarily rare object,” says Carey Lisse of Johns Hopkins University, who is coordinating an international observing campaign. “It isn’t just hyperbole. We are going to go to town on it. And we are going to learn a lot.”

Day of Discovery:


Almost as soon as they sighted the comet on a cloud- streaked autumn night in Russia’s North Caucasus, Vitali Nevski and Artyom Novichonok realized it was something special. They were performing a routine sky survey on Sept. 21, 2012, as part of the International Scientifc Optical Network, or ISON, a project that normally tracks rocky asteroids and space debris. This one smudge in their images was neither. “My heart missed a beat. Is it really a comet?” Nevski jotted down in his broken English.
When the two observers calculated the object’s orbit, their excitement mounted. The newly named Comet ISON was headed almost directly toward the sun, falling into the group of daredevil objects that astronomers picturesquely call sungrazers. Cold comets are small and unspectacular, but when they heat up, the ice and dust that blow off catch sunlight, forming a round cloud (the head, or coma, of the comet) and long streamers (the tail). That is what makes comets so beautiful and spectacular.
Because of its Icarus-like trajectory, Nevski and Novichonok realized, Comet ISON would put on an extreme performance, boiling away madly under intense illumination. “The brightness of the comet in the maximum could reach the full moon,” Nevski commented in his notes on Sept. 25, after the comet was formally announced. If so, Comet ISON would rank as the most brilliant comet since the Great January Comet of 1910 became easily visible in daytime skies. Even the newer, less upbeat forecasts suggest ISON will be lovely in binoculars.
For the casual sky gazer, a bright sungrazing comet means a delightful spectacle. For researchers like Lisse, it presents a rare opportunity to see exactly how a comet is constructed: By passing its light through a spectrograph that detects wave- lengths, they can identify the visual fngerprints of the various chemical components that are present. From estimating how much of each component is present, they can learn a lot about where and how the comet formed.
“I look at comets as the dinosaur bones of solar system formation. If we can crack open a comet, we’re going to be able to learn about the initial conditions that helped lead to the planets, and to us,” Lisse says.
There’s no need to fgure out how to crack a comet; solar radiation is already doing the job. “Comet ISON is going to get close enough that the sun will not only boil off all the icy parts of the comet; it’s going to boil the rock as well. It’s going to give us a chance to literally count atoms in the gas and the dust.”

The Plot Tickens:


Soon after the discovery in Russia, other researchers traced Comet ISON’s orbit backward to identify its point of origin. They found a path to the sun that looked nothing like the circle or oval traversed by most comets. Instead, Comet ISON’s trajectory was more like a straight line. Its journey started in the Oort Cloud, a vast swarm of inert comets that stretches from the edge of our solar system nearly halfway to the next star.
Suddenly the story got even more interesting.
Most of the comets that astronomers study have made previous journeys into the torrid inner reaches of the solar system, often multiple times, as they orbit the sun. As a result, they have been cooked, evaporated and eroded in ways that erase much of their original nature. Comet ISON, on the other hand, appears to be making its frst trip in from the Oort Cloud. Extending Lisse’s metaphor, Comet ISON is not just a bunch of dinosaur bones. It is more like the dinosaur itself. Comet ISON’s long trajectory has given astronomers yet another precious gift: a chance to prepare. Most sungrazing comets are scrappy objects spotted just hours before they race past the sun. That isn’t nearly enough notice to set up observing campaigns at big observatories, which must be reserved months in advance. “But Comet ISON was found when it was far from the sun, six times Earth’s distance, so we’ve had a lot of time to do observational planning,” says Jian-Yang Li of the Planetary Science Institute in Tucson, Ariz.


The Witnesses Assemble:


The first phase of that plan kicked off around the beginning of 2013, as observers around the world began monitoring Comet ISON and sending reports to the Minor Planet Center in Cambridge, Mass., the main clearinghouse for information about comets and asteroids. By spring, Karen Meech of the University of Hawaii had scheduled a session on the giant Gemini North telescope atop Mauna Kea. From those observations, she documented a vigorous outpouring of gas and dust from the comet.
Around the same time, Li led a team working with the famed Hubble Space Telescope, which clarifed the origin of the outpouring. The Hubble images captured an energetic geyser, almost 2,500 miles high (4,000 kilometers), shooting out from the sunward side of the comet. “I did not expect such an obvious jet, nothing as spectacular as that,” Li says.
That geyser partly explains why Nevski and Novichonok spotted the comet so far ahead of perihelion, but it opened up a deeper mystery. The most common ingredient in a comet is ordinary ice, so comets typically remain fairly sedate until they receive enough sunlight to vaporize water. Comets do not generally get that hot until they approach Mars. But there was Comet ISON, puffng away in the frigid realm beyond Jupiter.
Meech thinks such famboyant behavior refects the unusual makeup of comets that have never experienced any warmth from the sun. She notes that as a new arrival from the Oort Cloud, Comet ISON might be covered with a layer of frozen carbon monoxide and carbon dioxide, gases that vaporize rapidly when exposed to even a slight trickle of heat. “Carbon dioxide would be strongly outgassing as far out as the orbit of Saturn,” twice the distance of Jupiter, Meech says.
Veteran comet researcher Michael A’Hearn of the University of Maryland points to another possible reason why Comet ISON was unraveling so rapidly as it plummeted toward the sun. Solar wind creates a huge magnetic bubble, known as the heliosphere, that protects Earth and the other planets from energetic subatomic particles that constantly zip around in deep space. But in the faraway Oort Cloud, Comet ISON received no such protection.
“After four and a half billion years outside the heliosphere, the outer 10 or 20 meters of the comet has been completely irradiated,” A’Hearn says. “Essentially all the chemical bonds are broken down. You get lots of unstable molecular frag ments. When they warm up, even a little, they recombine and tend to do so explosively.” The outer layer of Comet ISON was like a thick blanket of TNT waiting for the slightest spark of heat to set it off.
Around April 2013, Meech and others noted that Comet ISON was no longer brightening so quickly. “I would interpret that as the end of the bomb,” A’Hearn says. The super-reactive molecules had mostly been consumed, and ISON was now behaving more like an ordinary comet.
At that point, astronomers realized they might have mis- judged Comet ISON based on its front-loaded performance. Drawing on his data from the Hubble observations, Li estimates that the nucleus — the solid body of the comet itself — is no more than about 2.5 miles (4 kilometers) across, smaller than what many astronomers initially expected for such an energetic comet. Although the comet’s tail may ultimately stretch millions of kilometers through the solar system, its nucleus is likely smaller than New York’s Central Park.
Likewise, Comet ISON probably will not become as bright as the early extrapolations had suggested; contrary to Nevski’s early hope, the comet is unlikely to rival the full moon. On the other hand, the dramatically changing nature of Comet ISON as it boils away is exactly what scientists were hoping for. With each new part of the comet exposed, a little more of its past — and our past — is revealed.

Celestial Hide and Seek:


And then, just as Comet ISON began to lower its death mask a little more, it vanished. The comet passed behind the sun as seen from Earth, and for two months, comet researchers were effectively blinded. That gave them some much-needed time to plan their next round of studies and to anticipate what to look for when the comet rounds the sun on Nov. 28.
The kinds of questions that observers like Li investigate are informed by an origin story that is substantially different from the one that was written into textbooks just a few years ago. In the old view, the planets formed in an orderly manner, born from a swirling disk of gas and dust, known as the solar nebula, into stable orbits at their present locations from the sun. That interpretation left many details unclear, though, including how comets like ISON got tossed all the way out to the Oort Cloud while others were sent crashing into Earth. Then the doubts multiplied.
The discovery of strangely ordered planetary systems around other stars showed that the formation process cannot be so tidy after all. Some planets hug their stars, move in wildly stretched orbits or even circle backward. Such arrangements are possible only if newborn worlds interact and migrate in complicated ways. Another surprising clue came from comets that apparently derived some of their material from relatively warm parts of the young solar system. In this new, more chaotic picture of the solar system’s early days, the planets seem to pass through a vagabond phase lasting a few tens of millions of years.
“It now seems clear to me — though I have not yet convinced everyone — that Jupiter must have migrated inward toward the sun during that time and then turned around and migrated back outward,” says A’Hearn. According to this theory, the other giant planets also shifted locations as they interacted with each other and with the thick disk of material swirling around the still-forming sun. Comet ISON got swept up in the drama.
A dynamic simulation of that process, carried out by A’Hearn’s colleague Kevin Walsh of Southwest Research Institute, sheds light on many long-standing puzzles about the solar system: not only where the Oort Cloud comets come from, but also why Mars is so small and airless com- pared with Earth. As Jupiter migrated, its intense gravity stirred up everything around. It siphoned off raw material that would otherwise have reached Mars. It sent baby comets scattering far and wide.
During its travels, Jupiter fung swarms of those comets on paths that ran right into the still-forming Earth. When some of the comets collided, they deposited their water. and organic compounds, helping to fll the oceans and turn our world into a blue planet. Then as Jupiter wandered away from the sun, A’Hearn explains, it stirred up a second, more distant group of comets and fung them out to the Oort Cloud. In this view, Comet ISON was one of Jupiter’s victims on the planet’s outward track.
Each part of it makes for a cracking good story — and Comet ISON can help prove it is true. Every piece of the solar nebula had a distinctive composition, determined by its temperature and distance from the sun. Looking at Comet ISON’s chemical fngerprints — its ratio of carbon dioxide to water, its mix of different kinds of hydrogen atoms, the kind of dust grains it contains — will indicate where it formed 4.56 billion years ago, and thus put the wandering- Jupiter theory to the test. The answers will not only help explain how Earth became an ideal place for incubating life; they will also tell a lot about the odds of fnding similar habitable planets around other stars.


The Moment of Life and Death:


Now that Comet ISON has come back into view, almost every major telescope on Earth is watching it careen toward the sun. So are a lot of telescopes in space because of yet another happy accident. “The comet happens to be going through the inner solar system when the planets are just aligned right,” says Lisse.
On Oct. 1, 2013, Comet ISON skirted just 10 million miles (16 million kilometers) from the Red Planet, where the Mars Reconnaissance Orbiter (MRO) was watching. And on Nov. 18, when Comet ISON slides 36 million kilometers past Mercury, another NASA spacecraft, MESSENGER, will be watching from there as well. Comet ISON grazed so close to Mars that MRO got the best view of any observatory in the solar system. It won’t get nearly as close to Mercury, but that passage will be important all the same. “At that time, it’s near impossible to observe the comet from the ground. That’s why we’re doing it, to look at the comet from different geometries and at different times,” Li says. Unfortunately, the most exciting moment of all, the perilous moment of perihelion on Nov. 28, will be impossible to observe using most ground-based telescopes because the comet will be so close to the sun; all instruments designed for nighttime viewing would be blinded by the light. Spacecraft orbiting other planets won’t be any help this time around for the same reason, but another set of instruments will step up: solar observatories like SOHO, STEREO and the Solar Dynamics Observatory, all of which are designed to stare straight at the sun’s surface. If anything spectacular happens as the comet rounds the sun, they will be watching.
Whether Comet ISON survives intact depends on heat and gravity. Heat turns out to be the lesser problem. Even at 2,000 degrees C, the outer layers of the comet vaporize more quickly than the heat can penetrate. Unless Comet ISON runs out of material — that is, it literally boils away — it should emerge still cool inside, like a giant baked Alaska.
Gravitational tides from the sun are another matter. Comets are loosely constructed. “If you were to scoop up a bunch of snow with your hand and do no more than that, that’s the way a comet is put together,” Lisse says. “It’s not an ice ball. More like a dirty snowbank.” In one particularly explicit example of such instability, another bright sungrazer, Comet Lovejoy, largely disintegrated after its swing around the sun two years ago. Li also recalls Comet Shoemaker-Levy 9, which was torn into at least 21 pieces by Jupiter’s gravity before colliding with the planet in 1994. Comet ISON could similarly fragment into a “string of pearls.”
So will the comet make it? Sooner or later, every researcher studying Comet ISON offers odds. “I’m not a gambling man, but if I had to put money on that, I would tend to gamble on it surviving,” says astrophysicist John Brown of the University of Glasgow. “I do play poker, and I’m a betting man, but I’m not going to bet the farm on it,” counters Lisse. A’Hearn takes a more exact position: “I’m prepared to bet a beer that it will survive. I’m not sure I’m prepared to bet a bottle of good Scotch.”
If Comet ISON comes out the other side, Meech, Li, A’Hearn and countless others around the world will resume their vigil, looking for changes in the shape and composition of the nucleus. But disintegration would in some ways be even more revealing because it would provide data on the comet’s internal construction — and, by extension, on the way it formed in the frst place. “If it fragments, that will expose more fresh interior, and we’ll be able to measure the strength of the comet and study why it fragmented,” Li says. And even if it breaks up, the fragments should still make for a stunning show in Earth’s skies.


The Afterlife of Comet ISON:


Whether it dies quickly or slowly, Comet ISON will be greatly diminished after Nov. 28. But nothing in the solar system is really lost. Material from the comet will spread, and some of that comet dust will hit our atmosphere on Jan. 12, when our planet passes through the edges of Comet ISON’s trail. Large chunks of the comet will miss us, but solar radiation will push tiny particles — about the size of those in wood smoke — to Earth. Less than a pound of these minuscule particles will eventually drift to the ground, predicts meteor researcher Paul Wiegert at the University of Western Ontario. “Cometary seeding is still going on much the way it did when the Earth was young,” he says.
As Comet ISON, or whatever is left of it, heads back out to the Oort Cloud, astronomers are keenly interested to see what happens next. “We’re going to try and observe the comet after it has left the inner solar system, and we’ll watch it turn off,” Lisse says. One by one, each of its chemical components will return to a dormant, frozen state.
Long after Comet ISON has disappeared from view, its legacy will continue in other ways as well. Lisse’s coordinated viewing effort, called the Comet ISON Observing Campaign, will make its datasets available to the public, so everyone can practice being a cosmic history detective.
Observations of Comet ISON from Mars will serve as a test run for another extraordinary cometary event: On Oct. 19, 2014, Comet Siding Spring will squeak by Mars, coming within 68,000 miles (or 110,000 kilometers) of the Red Planet — 100 times closer than Comet ISON’s closest approach. For comet scientists, this is an unprecedented opportunity. Comet Siding Spring will pass so close to Mars that the planet will slide right through the comet’s coma. Every probe orbiting Mars or roving around its surface will be recording the event.
“It happens to be a particularly good time for interesting comets,” A’Hearn says. It could get even better. Theoretical models of the Oort Cloud say that gravitational disturbances should occasionally shake loose not just individual comets like Comet ISON, but large batches. As A’Hearn drily puts it: “Comet showers are to be expected.” The odds that any of them would strike Earth are minuscule, but the effect would still be stunning.
The only question is whether you or I will live long enough to see not one but an entire storm of great comets, all racing sunward in a spectacular swoop of glory.

Bio Diesel A Future Fuel

introduction:

Biodiesel1 comprises mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fat (or mixtures thereof). When biodiesel is blended with diesel, the designation indicates the percentage of it in the blend, e.g, B2 [2% biodiesel, 98% diesel (v/v)] and B100 (pure biodiesel). Worldwide, the feedstocks for biodiesel production in greatest supply are soybean oil, palm oil and rapeseed oil (Fig. 1). When alternative fuels are considered, their energy contents and conversion efficiencies are of particular interest, even though petroleum based fuels require more energy to produce than what they contain. Biodiesel has tremendous potential in this respect. A life cycle analysis2 concluded that biodiesel yields 3.2 units of fuel product energy for every unit of fossil fuel used to produce it; other projections go as high as 3.6.

If biodiesel is to be accepted as a fuel for diesel (compression ignition) engines, it will have to be produced and handled in such a way so that the variations in it’s properties and performance characteristics will be less than or equal to what the consumer is used to with (petroleum based) diesel fuel. A single, widely accepted, standard for biodiesel is not available. Instead, the standard ASTM D675102 was developed for the USA. and CEN 14214 for the European Union (EU).

Conversion Technologies:

Transesterification (alcoholysis), most widely accepted and almost exclusively used technology for the conversion of natural fats and oils to biodiesel, is the reaction of a fat or oil with an alcohol to form esters and glycerol. Fat or oil will depend on what is available in the region of the biodiesel production facility, their respective prices and the flexibility of processing facility to handle multiple feedstocks. Alcohol is methanol because it is low cost, easily recyclable and toxic. Because the reaction is reversible3, excess alcohol is used to shift the equilibrium to the products side. Typical mole ratios of alcohol to triglycerides range from 5.25:1 to 6.1:1. A catalyst is usually used to improve the rate of reaction and yield. The amount (0.1-0.5 % v/v) and type (base vs acid) of catalyst used depends on the quality [free fatty acid (FFA) and moisture] of triglycerides. Even though conversion efficiencies are good with conventional transesterification and feedstock costs represent 65 to 75 percent of the cost of producing biodiesel, there are significant research interests in improving the process and thereby the economics of biodiesel production. These interests include the development and evaluation of heterogeneous catalyst systems, the use of ethanol, in situ transesterification, reducing NOx emissions, and adding value to the coproducts (oilseed meals/presscakes and glycerol). Additionally, efforts in the area of standardization of biodiesel will enhance its marketability. Heterogeneous catalyst systems have major advantages over the homogeneous catalysts currently used in biodiesel production. The use of heterogeneous catalysts will eliminate the need for a water wash to remove excess catalyst. This will reduce both the capital cost of a plant and the operating cost. It also is perceived that FFAs present in feedstocks, particularly in yellow and brown greases, could be converted concurrently to alcohol esters rather than being separated out and used for some other, lower value purpose. Yet another potential advantage is that a higher quality glycerol may be obtained.

Because ethanol is produced in large quantities from readily renewable resources and because it is more environment-friendly than methanol, there is interest in using it in biodiesel production. From a reaction standpoint, ethanol will work fine albeit the reaction may be slower. The primary problem arises in the recycling of the excess alcohol. Around twice as much anhydrous alcohol is used in the process as what is required stoichiometrically. The reclaimed ethanol will not be anhydrous with simple distillation as with methanol and there will be the issue of breaking the azeotrope before it can be reused.

In situ transesterification4, a method that utilizes the original agricultural feedstock as the source of triglycerides for direct transesterification, eliminate the hexane extraction process and works with virtually any lipid bearing material. In this process, soybeans are dehulled, cracked, rolled into flakes, dried to remove moisture and incubated in a solution of methanol and sodium hydroxide to yield fatty acid methyl esters (95-100 %). Similar research has been conducted with other feedstocks including distillers dried grains with solubles from ethanol production and meat and bone meal from animal slaughter and rendering.

Reducing the combustion temperature5 can reduce the increased NOx emissions resulting from biodiesel fuel or biodiesel fuel blends. Vaporized injection, rather than spray injection, better distributes the fuel and avoids hotter areas during combustion that contribute to NOx generation. Controlling the timing of engine using injection sensors that determine the concentration of biodiesel in the fuel and adjusting the timing accordingly can reduce the combustion temperature. Exhaust gas recirculation, which also results in a lower combustion temperature; and NOx traps similar to catalytic converters that store NOx and which are regenerated by injecting more fuel in the cylinder or upstream from the trap to convert NOx to CO2 and unreactive nitrogen. Exhaust after treatment combined with engine management controls appears to provide the best NOx reduction at this time. Adding value to the coproducts of biodiesel

production, or at least maintaining their current values, will enhance the economic viability of biodiesel. The oilseed meals/press cakes are used predominately as animal feeds. Their values as feeds or feed supplements are functions of their protein content and quality, and the need for additional processing to inactivate or remove anti-growth factors such as trypsin inhibitors and glucosinolates. Opportunities for adding value to the meals include industrial uses for the proteins, such as adhesives, and the extraction of higher value materials, such as policosanols. Glycerol, a coproduct of biodiesel production, may be used to produce 1,4 propanediol, a commodity chemical and a precursor for many products.

A universally accepted standard for biodiesel, and adherence to the standard, by all producers will enhance the acceptability of biodiesel and its blends, both by the blenders and the consumers. The primary difference in the current USA and EU standards is the way stability and iodine number are handled (ASTM D6751-02 and CEN 14214). This difference is traceable to soybean oil being the oil of preference in the USA as opposed to rapeseed oil in the EU.

Biodiesel Production and Use

Global Scenario:

The 1.0 billion ton of diesel fuel used annually

worldwide or even the 188 million tons used annually in the USA6 dwarfs the current and future production capabilities of the vegetable oil and animal fat industry. Hence, petroleum based hydrocarbons will continue to be the workhorse for diesel engines. Biodiesel use has the greatest penetration in the EU7 with an estimated 1.9 million tons having been used in 2004. The use of biodiesel in the USA1 pales in comparison, with an estimated 86 thousand ton used in 2003 and 120 thousand tons used in 2004. Production capacity is expanding rapidly in the USA, with an estimated plant capacity of 770 thousand tons and considering current and planned facilities, production capacity could exceed 1.5 million tons by 20078. Vegetable oil feedstocks, worldwide, are estimated to be 100 million tons9. Currently, rapeseed oil is the feedstock of choice for biodiesel production in the EU, soybean oil is the feedstock of choice in the USA, and the use of palm oil for biodiesel production is growing in Asia. A total for animal fats, worldwide, is estimated at 15 million tons10. The vegetable oil feedstocks, if converted to biodiesel by transesterification, and assuming roughly a volume per volume conversion rate, would supplant only 10 percent of diesel used in the world. Using the total animal fats, and assuming same conversion efficiency as for vegetable oils, equivalent biodiesel production would amount to an additional 1.5 percent of the diesel use in the world.

USA Scene

Soybean oil carryover in the USA has been

between 450 to 900 thousand tons, of which only 225 to 450 thousand tons (< 0.3% of total diesel fuel use in the USA) can be diverted to biodiesel industry. Other edible oils (corn, cotton, sunflower), which account for around 1.6 million tons of total consumption, are typically higher priced than soy and unlikely to be used for biodiesel purposes. However, 450 thousand tons of soybean oil represents 5 percent of total domestic soybean oil use and most of the current carryover stocks. Animal fats and waste greases are consumed for use in soap, food, feed, industrial and export markets. The historic price discount between these feedstocks and soybean oil has varied from 25-75 percent. In 2003, the total US tallow and grease production was 3.9 million tons. At the right price and assuming no technical barriers, a significant portion of these feedstocks, say 450 thousand tons, could be bid away from their current uses. It is expected that animal fats would be the feedstock of choice as long as it is priced below soy and biodiesel demand rises. In summary, the total available feedstocks in the USA that can be readily converted to biodiesel are 450 to 900 thousand tons, which is less than 0.6 percent of the diesel fuel used in the USA.

In the USA, both vegetable oils and animal fats are imported and exported. If biodiesel demand exceeds the estimated demand benchmark of 450 to 900 thousand tons, domestic to foreign fat and oil spreads would widen and exports would decrease, imports would increase or both. Some USA based econometrics were used to predict price impacts from a demand shock. Assuming petroleum diesel fuel stays at historically high prices of around $0.32 US/l (rack untaxed) and that soybean oil is $0.51 US/kg, approx 300 thousand tons of soybean oil demand would raise the price of soybean oil $0.07 US/kg and 680 thousand tons would raise it $0.14 US/kg. This would cause B2 blends to move from a slight discount to diesel to a premium between 300 and 680 thousand tons of use. As a result, at current diesel fuel prices, biodiesel can only pull about 300 thousand tons from domestic soybean oil supplies before B2 blends move to a premium over diesel. After that, either B2 must be sold at a premium or trade flows will be impacted to keep feedstock prices in check

Future Prospects:

Future raw material availability for biodiesel production, worldwide, is significant. Additional sources include expanded oilseed production, higher oil content varieties, and substitution of higher oil content crops. In the USA, it is estimated that roughly expanding oilseed production by releasing productive land currently in government set aside programs 4 million ha and switching from lower value small export grains, 8 million ha could produce additional vegetable oil feedstocks of 2.1 million and 4.2 million tons. If the average oil yield from soybeans would improve to 20 percent versus the current 18 percent, which has been proven with several improved varieties, an additional 800 thousand tons of vegetable oil would be available, or if future improvements could increase oil yields to an average of 22 percent oil, 1.60 million tons would be available. If oil demand outpaces protein demand, soybean production could be replaced with higher yielding oil crops such as sunflower and canola, which produce approx 100 l/ha more oil than soybeans. Assuming soybean production at 29 million ha12 and a 20 percent conversion to higher yielding oil crops an additional 2.6 million tons would be available. Overall, conversion of all existing and potential feedstocks in the USA will not generate more than 12 percent of the diesel demand. Therefore, biodiesel will be consumed primarily in niche markets: 20% biodiesel blends for emission benefits and 5% or less blends as a fuel additive for lubricity benefits in ultra low sulfur diesel fuel11.

Conclusion:

The opportunities for expanded biodiesel production are bright considering the high demand for petroleum products in both industrialized and developing regions of the world. As a result, the increased awareness of the negative environmental factors associated with petroleum fuels and a desire to move to renewable fuels, biodiesel production is growing significantly. However, it represents only a small fraction of the current diesel fuel demands. Even as biodiesel production and available feedstocks expand, that growth will be challenged to keep pace with the growing demand for renewable or diesel fuel. Biodiesel feedstock availability, the price, and the resulting by-products, combined with government incentives based on economic or environmental issues, ultimately will determine the competitiveness of biodiesel as a direct substitute for petroleum diesel. It is anticipated that biodiesel will drive the industrial applications for vegetable oils and animal fats but will not displace food applications which will continue to lead vegetable oil price for most desirable oils, while lower grade oils will become industrial feedstock. Conversion technologies will continue to improve and will allow biodiesel production to remain competitive as government incentives are phased out.

Silicon:A Versatile Material

The ability to fabricate tens of millions of individual components (diodes, transistors etc.) on a minute silicon chip has enabled the modern information age. Now a days the essence of this silicon IC technology is almost a household word.

 The word ‘Silicon’ originated from silicium (Latin), meaning what was more generally termed as “the flints” or “Hard Rocks”. It is an abundant non- metallic element found throughout the Universe. On earth, silicon is one of the most common elements after oxygen and carbon. It was first discovered as an element by a Swedish chemist named Jacob Berzelius in 1824. He prepared amorphous (non-crystalline) silicon through the heating of sodium (Na) and silicon-tetrafluoride (SiF4). The first crystalline silicon was prepared by Henry Sainte-Claire Deville in 1854. But the popularity of silicon blossomed with the invention of the silicon Integrated Circuit (IC) – a revolutionary concept in the field of electronics.

 Only a small portion of the total silicon consumption is used up in IC technology. Silicon finds application in many areas starting from steel, alloys, bronzes, solar cell, MEMS to the biomedical sector. Additionally, silicon-based fertilizers have been proved to have plant susceptibility to fight diseases.

 Raw Material and Purification:
 Naturally occurring silicon is in impure form mixed with a host of other minerals. Therefore, it must be refined to different grades and finally converted in to crystalline form. This is usually a multistage process.
 First of all quartzite (a type of sand that is the source of silicon) with carbon source (like coal or coke) is heated in an arc furnace at an elevated temperature (~20000C) resulting in 98% pure metallurgical grade silicon (MGS). Most of the silicon that is used in the industry is of the MGS form. A small portion of this MGS is purified further to electronic grade silicon (EGS) for Solar cell and IC industry.
 For this, the MGS is first converted to Tri-chloro-silane (SiHCl3) by reacting with gaseous HCl. SiHCl3 is liquid at room temperature, therefore, by fractional distillation process it can be purified to electronic grade. Pure SiHCl3 is decomposed at an elevated temperature in to electronic grade polycrystalline silicon.
 The single crystal of silicon is grown by Czochralski (CZ) technique. Here the pieces of EGS are placed and melted (14000C). A seed crystal is immersed into the surface of the melt and then slowly withdrawn while rotating resulting in a single crystal silicon ingot. Later the ingot is sliced into thin wafers and polished. Such silicon wafers are used for fabrication of IC, Solar cell and MEMS based devices .


Applications of Silicon: IC Industry Silicon gained popularity and mass recognition with the advent of the Integrated Circuit (IC) industry. IC is a miniaturized electronic circuit consisting of numerous transistors, diodes, resistors and capacitors built on a common substrate and interconnected to perform desired functions. In most of the cases silicon is chosen as the basic semiconductor substrate because of many technological advantages. Currently, about 88% of the IC market is MOS (Metal-Oxide- Semiconductor) based and about 8% is BJT (Bipolar Junction Transistor) based. Remaining 4% is based on compound semiconductor for high frequency applications [Source: Solid State Electronic Devices, 5th Ed., by B.G. Streetman & S. Banerjee].
Jack Kilby of Texas Instruments was the first to demonstrate the monolithic arrangement of electronic components on germanium in 1959 and thus the IC was born. Almost simultaneously, Robert Noyce of Fairchild Semiconductor demonstrated IC on silicon ushing in the technological revolution. The transistor count in an IC chip since then has roughly doubled every 18 months (Moore’s Law). Modern computing, communications, manufacturing and transport systems, all depend on the existence of integrated circuits. Today the most advanced circuits on a chip contain several hundred millions of components. The ICs can be classified depending on the component count The main factor that has enabled this increase in transistor count is the ability to shrink or scale-down the device feature size largely facilitated by a very stable Si-SiO2 system. While scaling represents an opportunity, it also presents tremendous technological challenges like photolithography, etching, doping, thin film deposition, and packaging. Moreover, small feature size also requires device fabrication in extremely clean environments (Clean Room).

Silicon steel & Silicon bronzes:
Silicon like manganese is present in all steels as a cheap deoxidizer. When steel contains more than 0.60% silicon, it is classified as silicon steel. It is the most important soft magnetic material in use today and has important physical properties like increased resistivity, decreased hysteresis loss, increased permeability and negligible aging compared to the earlier soft magnetic material – iron. Use of silicon steel varies in quantities from the few ounces used in small relays or pulse transformers to tons used in generators, motors and transformers. The term bronze was originally applied to the copper-tin alloys; however, this is now used for alloys of copper and tin/aluminum/silicon etc. Commercial silicon bronzes, which generally contain less than 5% silicon, are single-phase alloys. These are the strongest of the work hardenable copper alloys having mechanical properties comparable to mild steel and corrosion resistance comparable to copper. Silicon bronzes are used for tanks, pressure vessels, marine construction and hydraulic pressure lines.

Solar cell:
Solar energy is often expressed as the most promising secure and environment friendly alternative energy source. In a solar cell, electron- hole pairs are produced by absorption of light (solar radiation). These pairs are then separated by the electric field present in the cell (p-n junction). Although space quality solar cell is fabricated on GaAs substrates, nearly 90% of solar cell in the world (for commercial application) is made from refined, high purity crystalline silicon. But the growth of both IC and solar cell industries has put increasing pressure on relatively limited supplies of high quality silicon, consequently driving up the price. But researchers have now found a cheaper form of silicon, dirty silicon (silicon with metal impurity and defects), which could pave the way for cheaper solar energy

 Silicone: The second largest application of pure silicon is as a raw material in the production of silicone (about 40% of the world consumption of silicon). It is a durable synthetic resin with a structure based on chains of silicon and oxygen atoms with organic side chains. By varying the -Si-O- chain lengths, side groups and cross-linking, silicones can be synthesized with a wide variety of properties and compositions. Various organic groups such as methyl or the benzene ring may be bonded to the silicon They can vary in consistency from liquid to gel to rubber to hard plastic. Properties like thermal stability, flexibility, good electrical insulation, low chemical reactivity and toxicity make silicone a versatile material. It also has excellent resistance to oxygen, ozone and sunlight. They find many uses in oils, greases, and rubber-like materials. Silicone oils are very desirable since they do not decompose at high temperature and do not become viscous. Other silicones are used in hydraulic fluids, electrical insulators and as moisture proofing agent in fabrics. Silicone is also used in mold- making material to create rubber molds that can be used for production casting of resins, foams, rubber and low-temp alloys. Multiple layers of silicone often insulate automotive spark plug wires. Electronic components are sometimes protected from environmental influence by enclosing them in silicone. This increases the stability against mechanical shock, radiation, vibration Silica, as sand, is a principal ingredient of glass, one of the most inexpensive of materials with excellent mechanical, optical, thermal and electrical properties. and especially the electrical insulation. Silicone has many more biomedical applications such as artificial breast implants and contact lenses etc.

 MEMS:
 The field of MEMS (Micro Electro- Mechanical System) was originated by Prof. R.P. Feynman in 1959, when he delivered the famous lecture “There’s Plenty of Room at the Bottom”. In this lecture, he talked about manipulating and controlling things at the micro- level. It promises to revolutionize almost all the areas starting from microelectronics to micromachining technologies. The monolithic merger of micromechanics (Sensors and Actuators) and microelectronics (IC) leads to the evolution of integrated MEMS (I-MEMS) system on a chip. The economies of scale, ready availability of cheap high quality material and ability to incorporate electronic functionality make silicon attractive for a wide variety of MEMS applications. Mechanical advantage emerges from the fact that the single crystal silicon is almost perfectly obeying Hook’s law having no hysteresis and hence no energy dissipation. Also, the elastic constants of silicon are almost comparable with steel. Near absence of fatigue makes silicon-based mechanical structures highly reliable with service life times in the range of billions to trillions of cycles without breaking. Today, a wide variety of commercial MEMS devices like pressure sensor, accelerometer, gyroscope, RF MEMS and Bio-MEMS devices are available in the market. In defense and space applications MEMS based devices are widely used due to their small size, low power consumption, low cost and weight and high degree of reliability. The Solid State Physics Laboratory in Lucknow is working on development of a number of MEMS devices like Microbolometer, Vibration Sensor, Microaccelerometer, RF Antenna etc.

Silicon in Biology:

 Silicon also promotes firmness and strength in human tissues. It is part of the arteries, tendons, skin, connective tissue, and eyes. This mineral is also present with the chondroitin sulfates of cartilage, and works with calcium to help restore bones. Research shows silicon is important to plant and animal life. Results of studies on animals suggest that silicon may be essential to humans. This mineral is able to form long molecules, much the same, as in carbon, and gives these complex configurations some durability and strength. It represents about 0.05 per cent of our body weight. Human tissues often contain from 6 to 90 mg of silica per 100 grams of dry tissues. Lung tissue may vary from 10 mg in infancy to as much as 2000 mg per 100 grams in old age. Silicon is an essential element in biology, although only tiny traces of it appear to be required by animals. It is much more important to the metabolism of plants, particularly many grasses. The beneficial effects of adequate silicon include decreased susceptibility to fungal pathogens (and insects) and amelioration of abiotic stresses. Furthermore, rice is considered to be a silicon accumulator. Numerous studies have shown that the disease resistance of rice increases in reponse to silicon fertilization. In the form of sand and clay it is used to make concrete and brick; it is a useful refractory material for hightemperature work, and in the form of silicates it is used in making enamels, pottery, etc. Silica, as sand, is a principal ingredient of glass, one of the most inexpensive of materials with excellent mechanical, optical, thermal and electrical properties. There are also several forms of amorphous silica with water, such as the opal or the geyserite. From these, the black opal of Australia stands out, being one of the most valuable precious stones. Source author: Mr. Shankar Dutta is Scientist ‘C’ (shankardutta77@gmail.com) and Dr P. Datta is Scientist ‘G’ in the MEMS Division, Solid State Physics Laboratory, Lucknow Road, Timarpur, Delhi-110054; (pdatta2006@gmail.com)

Where Does The Internet Live

When you visit a website,content is sent over the internet of your browser from a web server.a computer system that stores a website data although any computer can act as a server with proper software and condition.This is costly and while some of the major online corporation support their own server rooms,most websites and companies take advantage of the convenient web hosting hospitality of a data centre.A business may have a dedicated server,or multiple users share one. these state of art facilities powers tens of thousand of servers,each capable of hosting hundred of sites.And because data centres hold sensitive information and are relied upon by bussiness,they have strict security regulation and environments controls to ensure security of data by staying operational 24 hours a day The 11server rooms at a data centre IV accomodates 660 racks of server,each capable of holding up to 80 servers all connected to the net.The temperature in a room containing thousands of constantly running processors is therefore controlled by 6 air condition to prevent overheating.Every room is equiped with sensitive smoke ,fire and water detectors to check air.In the event of fire argon gas or nitrogen gas is leaked in the room as argon is inert gas and spread over the room and chokes fire because it is inert and doesn't react with substances and engineers are hired to keepaway the phishing websites which steals the valuable data webservers and data centers are built in secret places to keep it safe.

The Apple Iglass A Competitor For Google Glass

Apple recently patented their upcoming gadget which is called the iglass having same functions like the google glass.it would be a complet computer infront of your eyes aking you feel like a cyborg doing tasks like playing games would be very immersive experience in these future spects although the apps are not many but development is going on.


 It would display all the tasks in realtime.the iglass will project these directly into your pupil using LED projector.in addition it will have 2 head mounted display as compared to google glass.

 The prototype of iglass is yet to be made beating apple google glass prototype is already available but expensive(to be released by 2014) Let's see will people adopt these fancy technology.