2021年经济学人 新款集水网--天网恢恢,疏而不漏(1)

（单词翻译）

Water supply

供水

A better fog trap

更好的雾网

A clever upgrade of a humble¹ but useful technology

一种不起眼但有用的技术的聪明升级

Every night, air cooled and moistened by the Humboldt current blows over Chile's northern coast and across the Atacama desert. The billowing banks of fog thus created might look insubstantial, but there is water here to be captured—and in this, the driest place on Earth, capture it people do. Fog-harvesting will never be big business, for it needs particular conditions to operate well. But in zones like the Atacama, where moisture-laden breezes bring fog but no rain, the invention in the 1960s of traps which can pluck that moisture from the air has helped sustain settlements otherwise on the brink² of drought.

每天晚上，洪堡洋流吹过智利北部海岸和阿塔卡马沙漠，使空气变得凉爽、湿润。由此产生的滚滚大雾可能看起来并不真实，但这里有水可以收集——在这里，在这个地球上最干燥的地方，人们是这样做的。雾收集永远不会成为大生意，因为它需要特殊的条件才能运作良好。但在像阿塔卡马这样的地区，潮湿的微风带来雾，但没有雨，20世纪60年代发明的网可以从空气中吸收水分，帮助维持住在干旱边缘的定居点。

Fog traps are polymer-mesh³ screens mounted in metal frames. As misty⁴ zephyrs⁵ blow through them, droplets⁶ of water adhere to the mesh. These absorb others until the result breaks free and runs down the screen, as a raindrop runs down a window pane⁷, into a collector. A typical trap, with a 40-square-metre collecting area, yields about 200 litres a day. That is enough to supply around 60 people with drinking water. Such a collector costs $1,000 or so, and will last a decade.

雾网是安装在金属框架上的聚合物网屏。当雾蒙蒙的和风吹过它们时，水滴就会粘在网孔上。它们吸收其他物质，直到释放出来并沿屏幕流下，就像雨滴沿窗玻璃流下，进入收集器。一个典型的雾网有40平方米的收集面积，每天可以产出约200升的水，足以为大约60人提供饮用水。这样的雾网价值约1000美元，可以用10年。

A simple idea, then. But even simple technology can be upgraded. And that is exactly what Urszula Stachewicz of the AGH University of Science and Technology, in Krakow, Poland, proposes to do.

这是一个简单的想法，但即使是简单的技术也可以进行升级。而这正是波兰克拉科夫AGH科技大学的厄休拉·斯塔切薇兹打算做的。

Her upgrade relies on giving the mesh a slight electrical charge. Overall, the molecules⁹ in it are electrically neutral. But polymer molecules are large, and their electrons can move about within them. Uneven¹⁰ distribution of these electrons means some parts of a molecule⁸ are positive and some negative. That fact might be exploited to give the outside of each thread in a mesh one electrical polarity (either positive or negative) while burying the other polarity in the thread's interior. Just as static electricity will attract a balloon to a wall, a surface charge created in this way will attract water droplets from the air.

她的升级方法是给网眼轻微的电荷。总的来说，它的分子是电中性的。但是聚合物分子很大，它们的电子可以在其中移动。这些电子的不均匀分布意味着分子的某些部分带正电，某些带负电。这一事实可能会被利用来给网中的每条线的外部一个电极性(无论是正的或负的)，而把另一个极性埋在线的内部。就像静电会把气球吸引到墙上一样，用这种方法产生的表面电荷也会吸引空气中的水滴。