German Telecom, Siemens, BMW and some German city councils have also
announced that they intend to use the new battery technology, which was
developed by physicists at the Jerusalem-based company Electric Fuel Limited
(EFL).

The battery has an energy density of 207 watt-hours per kilogram, which
is about four times better than a nickel-cadmium battery and ten times better
than a lead-acid battery, though still less than the energy density of
petrol or diesel fuel.

Most batteries now available for electric vehicles are heavy and expensive,
and last only a few years. A typical lead-acid battery configuration might
only power a vehicle for about 50 kilometres before needing to be recharged,
a process that takes hours. However, EFL’s zinc-air battery can work at
temperatures of -20 degreesC, does not discharge itself, and cannot burn
or explode.

This contrasts strongly with other leading technologies, principally
the sodium-sulphur battery, which BMW has spent millions refining. This
battery contains liquid sodium and sulphur at a temperature of around 300
degreesC, but loses power relatively rapidly if it is not recharged daily
(‘Flat out for the car of the future’, New ÐÓ°ÉÔ­´´, 7 November 1992).

The zinc-air battery also provides enough power to accelerate a vehicle
from standstill to 80 kilometres per hour in 12 seconds, reaching maximum
speeds of more than 120 kilometres per hour. Perhaps best of all, it can
be recharged in three minutes by changing the electrodes. Zinc-air batteries
work like a conventional alkaline dry cell; the oxidation that produces
the electricity is achieved as the oxygen in the air turns the zinc electrodes
to zinc oxide. New electrodes mean a fresh store of power.

The German parcel post service tested the EFL battery for several months
in a 3.5 tonne electric Mercedes vehicle laden with a tonne of goods. They
found that a 350-kilogram battery gave a range of 300 kilometres. Other
batteries of the same weight could only power the van for 40 kilometres.

Gunter Tumm of the German post office expects that by the end of the
decade the running costs of vehicles powered by zinc-air batteries could
challenge those for diesel. The current cost of a van powered by a zinc-air
battery is DM1.40 per kilometre travelled, compared with 40 pfennigs for
a diesel-fuelled van. If the costs of batteries and fuel were more comparable,
observers think the environmental benefits of electric vehicles would give
them the edge.

The virtual keyboard could be one solution to a problem that has recently
stumped designers of portable computers. While the machines themselves
are getting smaller and lighter, the human hand, of course, remains the
same size – placing a lower limit on the keyboard size, and hence the weight
of the machine. Small handheld computers have smaller keys, but most people
have to poke at them with just a couple of fingers, making typing at speed
uncomfortable and inaccurate.

The virtual keyboard would make it possible to take a computer practically
anywhere. It could also reduce maintenance, since dust buildup in the electrical
contacts of keys tends to make them unresponsive. Mechanical parts are
also prone to breakage. A computer with a virtual keyboard could almost
be a sealed unit, except for sockets and disk drives.

The idea emerged from IBM’s production centre in Sindelfingen, Germany,
which envisages applications in places such as operating theatres – where
standard keyboards, which are almost impossible to sterilise, are unwelcome
– and in public places where vandalism is a risk, such as information points
and vending and cash machines. The video camera sends 25 pictures a second
to the system to follow finger movements, which are interpreted by a program
requiring only 7 kilobytes.

People who do not touch-type could use the virtual keyboard with the
help of a paper template, spread out on a convenient surface to guide their
fingers. By changing the position of the camera, it might also be possible
to enlarge the virtual keys. Presently, though, the product is about two
years away from commercial production, though IBM does intend it for use
with PS/2 personal computers.