Tech Universe: Tuesday, 28 May

By Miraz Jordan

Charging your phone could soon only take 20 seconds. Photo / Thinkstock
Charging your phone could soon only take 20 seconds. Photo / Thinkstock

SPEED CHARGE: Charging a cellphone seems to have grown quicker over the years, but Eesha Khare of California thinks it should take only 20 seconds. She's invented a tiny flexible supercapacitor that can last for 10,000 charge-recharge cycles, compared with 1,000 cycles for conventional rechargeable batteries. So far she's only used her supercapacitor to power an LED but she says it could fit inside cellphones and other portable electronics. There's only one question: how soon?

GROW YOUR OWN GRAPHENE: What do hemp and graphene have in common? It turns out you can make one from the other, according to researchers at the University of Alberta. Graphene is ideal for use as electrodes in batteries and supercapacitors, but it costs a lot to produce. Hemp is relatively inexpensive because the plant grows quickly and easily. One part of the plant called bast is usually just wasted, but process it the right way and it separates into nanosheets similar to graphene. Bingo, the hemp can be used as an electrode.

So, that makes all parts of the plant useful then?

TRUCK IN A BOX: The Ox is a truck designed for Africa. 6 of the trucks fit into a single shipping container when packed flat. Then each truck takes 3 people less than 12 hours using standard tools to assemble — no high-tech engineering degree required.

The low-cost front-wheel drive vehicle is powered by a 2.2 litre diesel engine, weighs 1.7 tons, and can carry a maximum payload of 2.2 tons. It also has a wide track, high ground clearance, short front and rear overhangs, and can apparently drive through water nearly a meter deep. It sounds as though it would also be easy to fix and maintain.

WATER IN THE TANK: It's all very well having a wind farm out at sea, but ensuring a constant and steady supply of electricity is tricky. Norwegian scientists have suggested using an underwater battery system. A tank sits on the seabed at a depth of 400 to 800 metres. Open a valve and water flows in to start the turbine turning, generating electricity. When the tanks are full electricity is used to pump the water out again, perhaps taking excess energy from wind turbines or solar panels. The deeper the tanks are sited the greater the water pressure difference and the more energy is stored. One has to wonder how fish fare in all of this.

MIX AND MATCH: Wind energy or ocean power? In Japan they're not choosing between the two, but incorporating both into a single turbine. Mitsui Ocean Development & Engineering Company's hybrid system combines a floating vertical-axis wind turbine with an underwater turbine that generates power from ocean currents. The hybrid effectively doubles the efficiency of a typical wind or ocean current turbine. The wind turbine portion is expected to be 47 metres tall, while the underwater portion will be 15 metres in diameter. Each turbine could generate enough energy for 300 households. Go on, add some solar panels.

Miraz Jordan, knowit.co.nz

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