Scraps of food could soon be helping power your home, thanks to an ultra-cheap bacteria-driven battery. Its developers hope that instead of feeding the dog or making garden compost(混合肥料), organic household waste could top up your home's electricity.
Although such "microbial fuel cells"(MFCs)have been developed in the past, they have always proved extremely inefficient and expensive. Now Chris Melhuish and technologists at the U-niversity of the West of England(UWE)have come up with a simplified MFC that costs as little as ￡ 10 to make.
Right now, their fuel cell runs only on sugar cubes, since these produce almost no waste when broken down, but they aim to move on to carrot power. " It has to be able to use raw materials, rather than giving it a refined fuel," says Melhuish.
Inside the walkman-sized battery, a colony of E. coli bacteria produce enzymes that break down carbohydrates, releasing hydrogen atoms. The cell also contains chemicals that drive a series of redox, or reduction and oxidation reactions, stripping electrons from the hydrogen atoms and delivering them steadily to the fuel cell's anode(正极). This creates a voltage that can be used to power a circuit.
To prove the MFC works, the researchers are using it to power a small light-sensitive robot. When a number of the cells are connected in series, they could power domestic appliances, running a 40-watt bulb for eight hours on about 50 grams of sugar.
Earlier MFCs were inefficient because they relied on energy-hungry filters and pumps. By experimenting with different anode materials, the UWE team have figured out how to make their system work: they dump the bacteria and redox chemicals directly into the cell.
In its current form, the UWE team says its organic battery can produce eight times as much power as any previous MFC. But Melhuish wants to improve this, both by scaling it up and finding a better mix of redox chemicals.
单选题 Which of the following would be the most appropriate title for the passage?
【正确答案】 B
【答案解析】主旨大意题。综合各段的主题句可以看出本文主要是介绍一种成本低、产能高的新型微生物燃料电池。故选B。
单选题 Chris Melhuish and technologists are trying to use household wastes to______.
【正确答案】 C
【答案解析】细节题。根据第一段最后一句“…organic household waste could top up your home’s elec—tricity．”可知，使用家庭垃圾的目的就是发电，故选C。
单选题 The word "redox" in Paragraph 4 most probably means______.
【正确答案】 A
【答案解析】词义题。首先在文中找到该词所在的句子(第四段第二句)，本句中出现了对redox的解释or reduction and oxidation reactions(即氧化还原反应)。故选A。
单选题 Earlier MFCs were inefficient because they______.
【正确答案】 C
【答案解析】细节题。根据第六段第一句“Earlier MFCs were inefficient because they relied on energy—hungry filters and pumps．”可知，早期的MFCs低效是因为它们依赖于高耗能的过滤器和水泵。energy-hungry意思是“高能耗的”。故选C。
单选题 According to Melhuish, his present MFC______.
【正确答案】 D
【答案解析】推断题。根据最后一段第一句“In its current form，the UWE team says its organic batterycan produce eight times as much power as any previous MFC．”可知，新型有机电池产生的能量是从前的MFC电池的8倍，这说明这种型号的MFC效率已经很高了。故选D。
单选题 Which of the following statements is NOT TURE according to the passage?
【正确答案】 D
【答案解析】细节题。根据第二段第一句“Although such‘microbial fuel cells’(MFCs)have been developed in the past，they have always proved extremely inefficient and expensive．”可知，虽然微生物能源电池早在过去已经得到发展，但是却被证明是非常无效且昂贵的。A、B是正确的。根据第五段最后一句“When a number of the cells are connected in series，they could power domestic appliances…”可知，C也正确。D选项应该是“Organic batterycan produce eight times as much power as any previous MFC．”，有机电池产生的能量是过去微生物电池的8倍，所以D不正确。故选D。