Monday, September 17, 2007

Saturday, September 8, 2007

Forget biofuels - burn oil and plant forests instead




It sounds counterintuitive, but burning oil and planting forests to compensate is more environmentally friendly than burning biofuel. So say scientists who have calculated the difference in net emissions between using land to produce biofuel and the alternative: fuelling cars with gasoline and replanting forests on the land instead.
They recommend governments steer away from biofuel and focus on reforestation and maximising the efficiency of fossil fuels instead.


The reason is that producing biofuel is not a "green process". It requires tractors and fertilisers and land, all of which means burning fossil fuels to make "green" fuel. In the case of bioethanol produced from corn – an alternative to oil – "it's essentially a zero-sums game," says Ghislaine Kieffer, programme manager for Latin America at the International Energy Agency in Paris, France.


What is more, environmentalists have expressed concerns that the growing political backing that biofuel is enjoying will mean forests will be chopped down to make room for biofuel crops such as maize and sugarcane. "When you do this, you immediately release between 100 and 200 tonnes of carbon [per hectare]," says Renton Righelato of the World Land Trust, UK, a conservation agency that seeks to preserve rainforests.


Century-long wait


Righelato and Dominick Spracklen of the University of Leeds, UK, calculated how long it would take to compensate for those initial emissions by burning biofuel instead of gasoline. The answer is between 50 and 100 years. "We cannot afford that, in terms of climate change," says Righelato.

The researchers also compared how much carbon would be stored by replanting forests with how much is saved by burning biofuel grown on the land instead of gasoline.
They found that reforestation would sequester between two and nine times as much carbon over 30 years than would be saved by burning biofuels instead of gasoline . "You get far more carbon sequestered by planting forests than you avoid emissions by producing biofuels on the same land," says Righelato.

He and Spracklen conclude that if the point of biofuels policies is to limit global warming, "policy makers may be better advised in the short term to focus on increasing the efficiency of fossil fuel use, to conserve existing forests and savannahs, and to restore natural forest and grassland habitats on cropland that is not needed for food."
They do admit, however, that biofuels made from woody materials such as prairie grasses may have an advantage over reforestation – although it is difficult to say for now as such fuels are still in development.
Forests at high latitudes have been found to warm the climate . However, Righelato says this does not affect his calculations as biofuel crops are not, by and large, grown in these areas.
Journal reference: Science (DOI:10.1126/science.1141361)

Tuesday, September 4, 2007

THE "GÖMBÖC"

http://www.gomboc.eu/gomboc_english.html
http://www.sciencenews.org/articles/20070407/mathtrek.asp


This article is from sciencenews.org (link above)

The "Comeback Kid" is a wooden toy with an intriguing property: No matter which way you set it down—on its head, for example, or on its side—it turns itself upright. Two factors account for this: the object's shape, and the fact that the bottom of the toy is heavier than the top.


Set the Comeback Kid in any position, and it will turn itself upright. Theoretically, it's possible to balance the figure on its head, but the slightest breeze would knock it over and restore it to its upright stance.
P. Várkonyi

Give mathematicians such a toy, and they're liable to turn it into a math problem.

Mathematicians Gábor Domokos of the Budapest Institute of Technology and Economics and Péter Várkonyi of Princeton University wondered if they could make an improved version that wouldn't require the weight at the bottom to right itself. Could the shape of the object alone be enough to pull it upright?

Domokos, along with some colleagues, started experimenting with flat toys cut from a piece of plywood. They cut out shape after shape and found that the edges of each shape had at least two stable balance points. In addition, each shape's edges had at least two more points on which the mathematicians could balance it if they were very, very careful, but the slightest breeze would knock it over. They refer to those as "unstable balance points." (Similarly, it is possible, barely, to balance the Comeback Kid vertically on its head.)

Eventually, Domokos and Várkonyi managed to prove mathematically that for any flat shape, there are at least two stable balance points and at least two unstable balance points.

Next, the pair began to investigate whether all three-dimensional shapes have at least two stable and two unstable balance points. They tried to generalize their two-dimensional proof to higher dimensions, but it didn't hold up. Therefore, it seemed possible that a self-righting three-dimensional object could exist. Such a shape would have only one stable and one unstable balance point.

They looked for objects in nature that might have such a property. While Domokos was on his honeymoon in Greece, he tested 2,000 pebbles to see if he could find one that would right itself, but none did. "Why he is still married, that is another thing," Várkonyi says. "You need a special woman for this."

Eventually, the team managed to construct an object mathematically that has just one stable and one unstable balance point. The figure is like a pinched sphere, with a high, steep back and a flattish bottom. They sent their equations to a fabricator, who constructed the object. Várkonyi now keeps it in his office. "People like playing with it," he says.


Domokos and Várkonyi used mathematics to design this self-righting object.
G. Domokos


Once the pair had built their self-righting object, they noticed that it looked very much like a turtle. They figured that wasn't an accident, since it would be useful for a turtle never to get stuck on its back.

The shape of the Indian Star Tortoise is similar to the self-righting object that Domokos and Várkonyi created. When turned onto its back, its shape helps it come close to flipping over without effort, but the turtle needs to give itself a little boost by kicking its legs.
P. Várkonyi


Now, Domokos and Várkonyi are measuring turtles to see if any of them are truly self-righting, or whether the turtles need to kick their legs a bit to flip themselves back upright. So far, they've tested 30 turtles and found quite a few that are nearly self-righting. Várkonyi admits that most biology experiments study many more animals than that but, he says, "it's much work, measuring turtles."

The mathematicians still face an unanswered question. The self-righting objects they've found have been smooth and curvy. They wonder if it's possible to create a self-righting polyhedral object, which would have flat sides. They think it is probably possible, but they haven't yet managed to find such an object. So, they are offering a prize to the first person to find one: $10,000, divided by the number of sides of the polyhedron.

It sounds like a tempting challenge, but there's a catch: Domokos and Várkonyi are guessing that a self-righting polyhedron would have many thousands of sides. So the prize might only amount to a few pennies.





On August 20th 2007, in the main building of the Russian Academy of Sciences in Moscow, pre-eminent Russian mathematician V.I. Arnold received on the occasion of his 70th birthday the first piece of the planned limited Gömböc series (Gömböc 001) as a present from Várkonyi and Domokos. After playing a short time with Gömböc 001, professor Arnold told a further conjecture of his which might open up new avenues of research related to the Gömboc.

Sunday, September 2, 2007

My First Post Ever! Yay!

Whoppee! So this is it. Blogging. My first ever blog, and my first ever post! Wow. I actually don't feel very to excited.

Well, not really feeling like, or wanting to, post anything too heavy, I thought I'd just start with some of my favourite poetry, yay!

The first poem is  "my sweet old etcetera" by e.e. cummings:

my sweet old etcetera
aunt lucy during the recent

war could and what
is more did tell you just
what everybody was fighting

for,
my sister

isabel created hundreds
(and
hundreds) of socks not to
mention shirts fleaproof earwarmers

etcetera wristers etcetera, my

mother hoped that

i would die etcetera
bravely of course my father used
to become hoarse talking about how it was
a privilege and if only he
could meanwhile my

self etcetera lay quietly
in the deep mud et

cetera
(dreaming,
et
cetera, of
Your smile
eyes knees and of your Etcetera)

_______________________________________________________________

I must say, I am not really one for poetry, and I especially dislike poetry about love, unless it is quite unusual, or very good, such as the above poem.
Another one of my favourite poems is "Greater Love" by Wilfred Owen:

Red lips are not so red
     As the stained stones kissed by the English dead.
Kindness of wooed and wooer
Seems shame to their love pure.
O love, your eyes lose lure
     When I behold eyes blinded in my stead!


Your slender attitude
     Trembles not exquisite like limbs knife-skewed,
Rolling and rolling there
Where God seems not to care;
Till the fierce love they bear
    Cramps them in death's extreme decrepitude.


Your voice sings not so soft, -
     Though even as wind murmuring through raftered loft, -
Your dear voice is not dear,
Gentle, and evening clear,
As theirs whom none now hear,
     Now earth has stopped their piteous mouths that coughed.


Heart, you were never hot
     Nor large, nor full like hearts made great with slot;
And though your hand be pale,
Paler are all which trail
Your cross through flame and hail:
    Weep, you may weep, for you may touch them not.
____________________________________________________


Both cummings and Owen are two of my favourite poets (among others ofcourse), and these are just two, in my opinion, fantastic poems. cummings is the more famous of the two, but this is perhaps one of his less well-known poems. Owen is not a well-known poet, but I absolutely love his poetry, the way in which he portrays war truely, without the air-brushing, and I thought I would share his work with you all, who care to read this anyway.
You can read more about Wilfred Owen here