raj k. persaud

Tech Thursdays: One-Molecule Car Drives on Electron Fuel

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A report in today’s Nature describes an impressive feat of molecule-scale engineering: a four-wheel-drive “car” that can run across any conductive surface, powered by electrons.

The whole thing is a single molecule. Its core is formed by two hubs that have a five-ringed structure at their core. The hubs are connected by a rigid rod formed from carbon atoms, held together by triple bonds. Each hub is flanked by two “wheels,” each consisting of a three-ringed structure. The bulk of the molecule is a carbon backbone, with a small number of nitrogen and sulfur molecules thrown in.

 

The key to the system is the bond between the wheel and its hub, which is a double bond formed between two carbon atoms. Electrons can cause this double bond to rotate, which places part of the wheel in close proximity to a bulky side-molecule attached to the hub. This bulky piece acts a bit like a ratchet; the wheel requires some vibrational energy to get past it. Once it does, it’s positioned so that another dose of electrons can cause it to rotate again.

By repeating this cycle, the wheel will turn indefinitely in a single direction relative to the rest of the molecule. It’s worth noting that the wheel analogy is pretty inexact. The part of the molecule that rotates is actually much closer to a large, flat plate. If you could actually go for a ride with wheels like this one, it would be an extremely bumpy one, as the plate would lift the vehicle and then hurtle it forward as it went flat again..

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Featured Article: The Recokining-- Analyzing the Future of American Power

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Slate.com’s Michael Moran posted a sharply articulated piece today on the future of American power. As frequent readers of mine may know, this is a conversation with which I am continually engaged–the power dynamics of the American hegemon, especially as it transitions and locates itself within 21st century eco-political phenomena, is a fascinating narrative, and one, I contend, in which we all have a stake. Of course, as a political scientist and businessman, I cannot help but contemplate the trends I’ve witnessed in the past two decades. There is a rich story of complex social forces, economic momentum and political evolution at play, and it’s happening on a global scale.
I encourage you to read Mr. Moran’s piece though, I should warn you, it does not make for too happy a read. It is not all morose either– he ultimately presents a balanced, and in my opinion, an acutely realistic view of our impending futures.

“ [The] more serious measurements—potential growth rates, GDP per capita, GDP itself, only turned south relative to other global competitors recently.  It is only now, in the second decade of the post-American century, that these trends have penetrated the thick skull of the collective national consciousness…
[The] relative decline America has entered requires something a good deal more complex than fiscal austerity. The U.S. will remain the world’s most important nation well into this century—that’s not a question. How we handle the implications of our relative decline—not only at home, but around the world where we have maintained the balance of power in region after region since 1945—will matter enormously. Unraveling our global commitments in a way that does not prompt a geopolitical “Lehman Bros.” moment will be the true test of whether the United States was, as we like to believe, better than past hegemons.”.

Click here to read the full story

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I would also encourage you to read the comments on Mr. Moran’s article. I enjoy reading people’s rebuttals of his points or their mere discussion of what he’s brought up. Here is a notable comment which I hope might spur an internal dialogue in your mind:

By Robert Helbing:

Two points on the graph at top that underlies this entire analysis: 
 
1) Up until 1800, China was the world’s largest economy, and it had been since the demise of the Roman Empire’s trade networks in 420 AD (when the Vandals took Carthage). What you’re seeing on that graph isn’t a revolution; it’s a restoration. Europe’s rise to dominance after the Reformation was based on 3 technologies; ocean-going navigation, gunpowder and the printing press. All three technologies were invented in medieval China. After 1800 AD, China fell behind as the Industrial Revolution took off in Europe. Now that China’s adopted industrialization, it’s coming back to its usual place in the world. 
 
2) China’s rise will not go on indefinitely. China faces huge demographic challenges in the next 30 years. A combination of its “one child” policy and residual Confucian preference for sons over daughters has resulted in a collapse of the Chinese birth rate and an astonishing rate of abortion of female fetuses. This “gendercide” has seen hundreds of millions of female children never be born, resulting in an increasing imbalance in the sex of the ever-falling number of babies born to China. This is a huge social and cultural problem coming down the road for the Chinese. 
 
I’m not making light of the problems faced by America. Our international role is changing without question. But seeing China as some kind of demonic threat is ridiculous. A good rule of thumb about how people perceive a society’s future is its relative rates of emigration and immigration. China stills sees far more emigration that America and far less immigration. People are deciding where the future looks most promising, and are voting with their feet.