THIS ONE GOES UP TO ELEVEN
Anyone buying Denon’s new 1700-watt home-cinema amplifier will need deep pockets and a strong shelf. The Behemoth, as it is known, costs a cool £4000 ($7200) and weighs 41 kilograms, mainly because of the huge transformers needed to power its 10 surround-sound channels, each delivering 170 watts. Some of the Behemoth’s weight comes from an advanced audio processor that compensates for the distortion caused by sound reflecting off the walls. Developed by Audyssey Laboratories, a spin-off of the University of Southern California based in Los Angeles, MultEQ ensures that up to eight positions around a room will receive exactly the same sound. Previous systems could only fine-tune one listening position.
To set up the system, the amplifier sends a broad-frequency test signal to the 10 speakers while the user moves a microphone to each listening position. The circuit analyses the sound and uses filters to produce the best possible sound at the designated spots. The Behemoth will be launched in November.
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FAST FORWARD FOR FUEL CELLS
A new material that can store hydrogen gas at low pressure could help to make hydrogen-fuelled cars a reality. Hydrogen fuel cells generate energy cleanly – the only by-product of the process is water.
An efficient way to store the gas is in a cage-like molecule called a metal-organic framework (MOF). Existing MOFs are zinc-based, and need to be kept at pressures of around 20 atmospheres until the gas is needed (¿ìè¶ÌÊÓƵ, 24 May 2003, p 18), which makes storage dangerous and cumbersome.
Now Mark Thomas of the University of Newcastle upon Tyne in the UK and colleagues have found that a nickel-based MOF can store hydrogen at just 1 atmosphere of pressure (). Unlike the zinc-based one, the nickel MOF’s pores change size in response to temperature. To release the hydrogen, the pores are opened up by warming the material. The hydrogen is stored at −196 °C, and is squeezed out by warming the MOF to −159 °C, bringing it within the range of commercial application.
