经济学人下载:制造氧气(2)

A previous attempt by a different group of engineers used pulsed electromagnets. This, though, required both high pressure, which is expensive to create, and the electromagnets themselves, which are costly to buy and costly to run. Dr Vetrovec intends to perform his version of the trick at atmospheric pressure, and using permanent magnets. Both of these modifications greatly reduce power consumption. In fact, the device's only moving part is the blower which pushes air through it. 

此前，另一组工程师尝试使用脉冲电磁铁。不过这需要两种高压，成本很高，电磁铁本身的购买和运行成本就很高。维特威克博士想要在大气压力下使用永磁体来实现他的这种把戏。这两种改进都大大降低了功耗。事实上，这个装置唯一的活动部件就是推动空气通过的鼓风机。

It's a gas 

它是一种气体

The magic extra ingredient Aqwest brings to the party is an array of structures called microchannels. These are tubes less than a millimetre in diameter that are intended to carry liquids or gases. Crucially, their narrow bores ensure the laminar flow of any fluid passing through them. Translated from physics-speak, this means they cause no turbulence, and therefore no mixing of their contents. That allows them to act as gas separators in the firm's device. 

Aqwest给派对带来的其它神奇的东西是一组被称为微通道的结构。这些管道直径小于一毫米，用来运送液体或气体。最重要的是，它们狭窄的孔确保了任何流体都能通过它们的层流。从物理学的角度来说，这意味着它们不会引起湍流，所以里面的物质就不会混杂在一起。这一点使得它们可以在该公司的设备中充当气体分离器。

On the face of things, the initial results do not look that impressive. Prototypes yield a concentration increase of around 0.1% per passage, though Dr Vetrovec thinks his team can raise this to 0.4%. The key, though, is the repetition. Like the tale about a vizier who asked his king, as a reward for some service, for a grain of rice on the first square of a chess board, two grains on the second, four on the third, and so on, the oxygen concentration rises rapidly with successive iterations. Thirty passages at the higher rate would yield a 90% concentration of oxygen—and that would be commercially useful. 

从表面上看，最初的结果并没有那么令人印象深刻。虽然维特威克博士认为他的团队可以将浓度提高到0.4%，但其原型只给每个通道的浓度增加了约0.1%。然而，关键在于反复。就像有个故事说的那样，一个大臣向他的国王要一粒米作为某种服务的奖励，在棋盘的第一个方格上要两粒米，在第二个方格上要四粒米，以此类推，氧气浓度随着不断的迭代迅速上升。以更高的速率进行30次传代将产生90%浓度的氧气——这将具有商业价值。

Whether this approach actually will prove cheaper than the established alternatives, and whether, if it does, that will really save fossil fuels' bacon, remain to be seen. But some versions of a green-energy future involve the use of a lot of hydrogen, so better ways of generating that gas are always welcome. In the meantime, oxygen's many other users would surely welcome a cheaper source of supply. The idea of doing this with magnets is attractive. 

这种方法是否真的会比现有的替代方法成本更低？如果是，那么它是否真的能够节约化石燃料，这一点还有待观察。不过，一些绿色能源在未来的改版会涉及到大量的氢的使用，所以更好的制造氧气的办法总是受欢迎的。同时，氧气的很多其它使用者肯定会欢迎更便宜的供应来源。使用磁铁来制造氧气的想法很有吸引力。