Ammoniacal nitrogen can be present in two forms: ammonium ions and free
ammonia. Most instruments only measure ammonium ions, and so miss the ammonia,
which is toxic to fish.

Free ammonia can be measured using a gas-sensing membrane probe, but this
misses the ammonium ions, which are converted to ammonia under alkaline
conditions. To use this sensor to measure the total ammoniacal nitrogen, caustic
chemicals such as sodium hydroxide must be added to the sample to increase its
pH and convert ammonium ions to ammonia. These chemicals have to be handled with
care.

M²T’s solution uses optoelectronics. At the heart of the new instrument is a
sensor that has a dye trapped in a porous membrane backing onto an optical cell,
which fires light at specific wavelengths at the membrane. If there is ammonia
in the water the dye changes colour. This alters the intensity of the light
reaching a detector, producing a signal that can be converted to an ammonia
reading.

The other key element of the new device is a patented system that changes the
pH of the sample and converts any ammonium ions to ammonia. It works by passing
an electric current through an aqueous solution, splitting the water molecules
into alkaline hydroxyl ions and acidic hydrogen ions. The alkaline portion, in
which the ammonium ions have turned to free ammonia, then passes through the
optical cell.

The Environment Agency and the Department of Trade and Industry backed M²T
in its development of the probe.

I was not surprised to discover that I could indeed make a fortune buying
and selling water filters, and that water filters are the boom product of
the 1990s – just as microwaves were in the 1980s. I was told to act fast,
and the first step to this fortune was to sign a fat cheque – or preferably
lots of fat cheques in succession – to the Mega Water Filter Company Inc
(MWFC Inc) from Americaland, and Bob’s your uncle. That’s not its real name,
incidentally. MWFC Inc works like this:

Get to hear about MWFC Inc through one of its chain-sellers, or respond
to an advert it has placed, and you’d be loaned a video. This clever film
show will show you pictures of Big Bad Industry spewing all kinds of crud
into the air and rivers, followed by pictures of grotty water and such-like.
A deep-voiced, authoritative presenter with the obligatory mid-Atlantic
accent will guide you through this environmental carnage and lead on to
a child drinking a glass of water.

Needless to say, the water in the glass is dangerous unless it has first
passed through a water filter, because ‘leading scientists’ with ‘scientific
evidence’ say so. Every home should have a water filter – and most will
have, according to ‘leading marketing experts’, intones the mid-Atlantic
commentator. Then a series of graphs, charts and explanations tell you how
you will get rich by (i) buying MWFC Inc filters and reselling them, (ii)
persuading other people to do the same, (iii) persuading the persuaded to
persuade others, and so on. If this impresses you, then move on to Part
Two.

This takes place in a ritzy hotel and will have as much hype and religious
fervour as TV evangelism in the American Bible Belt. A first generation
of MWFC Inc followers will show you the ropes to the specially selected,
‘high calibre people’. Not that they will ask for evidence of a disciple’s
calibre. Just your money. You then buy as many filters as you want, and
then resell them at a mark up of 50 per cent. You also buy a licence which
allows you to buy and sell MWFC Inc filters – a vague franchise arrangement,
but with little of the backup associated with franchises.

Then you are on your own until, to use the MWFC Inc hype, you reach
Multiple Dimension: beget several generations of the persuaded, and not
only does MWFC Inc give you a small commission for each filter sold, but
it will then give you a budget for marketing. You can actually get quite
rich once you have reached Multiple Dimension, and a few people have. Yet
these are the kind if people who could succeed at anything.

For normal people, caveat emptor applies. First, you pay for the filters
up front and the onus is on you to resell them – forget about sale-or-return
arrangements, or invoices with 30 days’ credit: if your sales acumen should
abandon you on the long, costly path to Multiple Dimension, then it’s no
skin off MWFC Inc’s back because it has sold at least one more filter, and
there are plenty of people waiting to fill your vacant footsteps. Secondly,
until you reach Multiple Dimension, you pay your own overheads. In these
circumstances, a 50 per cent mark-up is pitiful. You would have to sell
one hell of a lot of filters very quickly to make it really worth while.

Thirdly, chain selling is like chain letters: just about everybody gets
them and loses a few pennies, but hardly anyone gets rich from them. So
in cold, commercial terms, MWFC Inc not only gets sales people to work for
commission alone – effectively working for nothing – but persuades them
to invest in the company’s growth and pay its sales overheads too.

MWFC Inc filters are also expensive even at the ‘wholesale’ price –
after lots of investigating at plumbing shops, builder’s merchants and adverts
from various sources, I discovered that several companies produce comparable
filters which cost as little as a third as much. So why do people get sucked
in by the hype?

Apart from the dangling carrot which draws you to the riches of Multiple
Dimension, environmental scaremongering helps a great deal. This is a marketing
ploy used by other manufacturers of water filters too. For example, ‘Do
you really care whether you and your family are healthy? Then use a water
filter,’ commands an advert for a British filter. A German producer tries
to persuade us to buy its filters because, once again through ‘scientific
sources’, ‘no area in Britain meets EEC standards for drinking water’. This
raises two issues: is Britain’s drinking water so dire, and are water filters
the answer?

First, the water. Most of it derives from aquifers in the ground. Before
being pumped on to users, it goes through an array of treatment plants to
purge it of contaminants such as pesticides, nitrates, fertilisers, bacteria,
heavy metals and sediments. Inspections are now made daily by the water
companies, and an independent watchdog – the Drinking Water Inspectorate
– makes spot checks to ensure that standards are maintained. In Britain,
water companies have to comply with about sixty parameters, and many of
these are aesthetic standards.

According to a spokesman from North West Water, ‘Ninety-nine per cent
of the time, our water is well within EEC guidelines. Exceedances do happen
though, but these are usually short term peaks and there is no evidence
to show that these peaks are as dangerous as the vendors of water filters
claim.’ Yet these vendors of water filters will readily quote these peaks
as if they are a continuous violation of the standard.

That said, accidents can happen, and the aluminium content, for example,
can soar to potentially dangerous levels. Whether these can be avoided or
not is a moot point. The water companies say they are tackling the problems,
especially where nitrates and aluminium are concerned – aquifers in some
areas of Britain are burdened with high levels of nitrate. But are domestic
water filters the answer?

Water filters mimic some of the simpler aspects of the groundwater treatment
plant. The most common types comprise a candle of ceramic material and activated
charcoal impregnated with silver. These will remove most of the heavy metals,
sediments, and organic residues, while the silver will kill any bacteria
present. It is tried and tested technology, and it works well – they can
go a long to cleaning up dirty water. There are, however, several caveats.

First, they are not designed to cope with pollutant peaks associated
with disasters. Secondly, while they are extremely efficient for the first
litre of water, their performance declines steadily. Ask the candle to do
too much, and after a time, the contaminants will be released back into
the water. Thirdly, few will remove all nitrates or lead.

So should we bother with water filters at all? Keith Osborne, an occupational
health expert with North West Water, says: ‘They are very good for aesthetic
reasons. They are also great for removing chlorine – dis-infectants are
necessary but they do not taste good. However, we disagree that water filters
are essential to bring potable water up to European Community standards
– it’s scaremongering.’

So what about lead in water? In our town, for example, potable water
often exceeds European Community standards because of the abundance of lead
piping in the ancient houses which dominate the place. ‘There are three
answers to that,’ says Osborne. ‘You can replumb and remove the lead pipe,
or you can let taps run for up to a minute before you use the water for
consumption, or you can use a filter. Just make sure it contains ion exchange
resins, or it won’t remove lead.’ I posed the same questions to a Fellow
of the Institute of Public Health Engineers, and got similar answers.

So there you have it. Next time someone tells you that all areas of
Britain suffer from undrinkable water and insists that you need to buy a
water filter for health reasons, they are probably selling them. And if
someone offers you membership of a chain sales scheme for water filters,
bear in mind that only a few get rich. So long as water quality is not perfect,
someone somewhere will exploit the fact.

Water quality seems to be improving in Britain and the rest of the Western
world. Meanwhile, in the Third World, around 30 000 children die every day
through water-borne diseases. All they need is clean water. Perhaps they
would find better use for water filters than us.

Richard Gould is a freelance journalist.

Uta Maier-Maercker and Wolfgang Koch from the Centre for Botany Research
in Munich found that the stomata of spruce trees (Picea abies) exposed to
ozone cannot open or close as efficiently as those of healthy trees (Plant,
Cell and Environment, vol 14, p 175). Stomata are the pores on plant leaves
through which water evaporates; in dry conditions they close. Carbon dioxide
for photosynthesis and gaseous pollutants enter leaves by the same route.

Maier-Maercker and Koch exposed young spruce trees to up to 175 parts
per billion of ozone and measured the rate of transpiration from their leaves
from 80 per cent humidity to drought conditions. Other trees were exposed
to very low levels of ozone.

The researchers found that the closing and opening of the stomata of
ozone-damaged trees was irregular and delayed. In humid air, rates of transpiration
were initially high, so the leaves lost a lot of water. In dry air, the
rate of transpiration soon fell far below those of healthy trees because
they had lost water. In control trees, transpiration rates fell steadily
with humidity and soil moisture.

Researchers at the Swedish Environmental Research Institute (SERI) in
Gothenburg have seen similar trends: ‘We have been looking at trees exposed
to ozone and drought stress, and we are also finding loss of control, especially
in drier conditions. The stomata are less responsive when conditions change,’
says Per-Erik Karlson, a plant physiologist. A team led by Terry Mansfield
of Lancaster University discovered that birch leaves exposed to sulphur
dioxide are less able to reduce water loss.

But, Tom Sasek, a forestry researcher at Duke University, disagrees:
‘We have always found stomatal closure after exposure to ozone. We see a
decrease in photosynthesis due to ozone, which results in a build-up of
carbon dioxide in the leaf. This in turn triggers the leaf to close the
stomata so that gas uptake and water loss are re duced.’

‘If you do match bag to passenger, you are 99 per cent on the way to
a safe flight,’ said Derek Dempster, a member of the Air Transport Users
Committee, an independent body which advises the Civil Aviation Authority
in the interests of passengers.

The Pounds sterling 8 million system will be installed at Heathrow Airport’s
Terminal 4 by the British Airports Authority and British Airways. Although
the BAA and BA will be the first aviation companies to install the system,
the International Air Transport Association (IATA) has stipulated that all
carriers that transfer baggage to other carriers will eventually have to
use bar-coded luggage tags to ensure compatibility between systems.

The BAA owns Heathrow airport, and has invested most in the development
of the system, while BA are the principal users of Terminal 4, and handle
the baggage for other airlines which use this terminal.

The integrated system is being assembled and tested by BAE, a company
based in Dallas, Texas, and software engineers are currently there finalising
the computer programs. According to John Peacock, BA’s manager for baggage
automation, ‘If next week’s trials go as planned, then the complete system
should be up and running by November.’ Other airlines are waiting to see
how the BAA and BA fare.

Presently most baggage at airports is sorted manually. Some airports,
particularly in the US, have introduced a semi-automated system which uses
luggage labels with printed bar codes containing information relating to
the flight and destination of the bag and laser scanners on the conveyor
belts. The scanner conveys this information to a computer which will then
activate the appropriate gate so that the luggage is directed to the correct
loading bay.

The new system will still use bar codes, but instead of the code relating
to the flight, it encodes a registration number for each bag which is stored
in the passenger record in BA’s main computer. Once a passenger has handed
over their ticket and checked in their baggage, the computer issues a registration
bar code, which is printed immediately on both the luggage tag and the baggage
receipt.

The tag will be read by four laser scanners grouped together on the
conveyor to give an all round field of view of the luggage. The scanners,
developed by Accusort of Pennsylvania, will be linked via modems to the
central computer. At the plane, another scanner will read the label to check
and record that the bag has been loaded and where it is in the hold. If
a bag is loaded onto a plane but its owner fails to board, the bag must
be removed for reasons of security.

A few airlines are already using this system of bar-coded labels and
checking baggage onto the plane with hand-held laser scanners, similar to
those found in many supermarkets.

The new system will also use hand-held scanners but they will be linked
directly to the central computer via a radio to allow constant communication.
The developers are currently waiting for approval by the DTI for the radio
link. The devices are now approved in the USA.

For the future, Peacock says that the BAA and BA are interested in using
luggage tags containing a simple computer chip, or ‘smart labels’. ‘The
advantage of smart labels is that they can be detected in the dark, and
viewed from any aspect.’

The system is the work of Bill Mathauser, an American aircraft engineer.
At its heart is a cylinder containing a piston and a rolling diaphragm made
from a fabric-like material used in the aerospace industry. This material
is strong, flexible and impervious to fluids under pressure. Mathauser calls
it a Bellowphragm. It rolls in the clearance space between the cylinder
and the piston, producing a perfect seal.

The piston connects to the brake shoe via a hexagonal rod, which prevents
misalignment caused by twisting forces. The brake uses a piston instead
of the pivoted callipers found on cable brakes. This makes it the only brake
to approach the wheel rim at a 90-degree angle. The use of hydraulics means
that there is no cable friction and no stretch, so less effort is needed
to operate the brakes. The system is more responsive to the touch.

The design makes it possible for the front brake to be located behind
the front fork, so the braking force is transmitted through the fork blades
rather than going through the pivot bolt, which is considerably weaker.
With conventional brakes, it is difficult to put the front brake behind
the front fork because the cable gets in the way. The new brakes are also
lighter than most conventional brakes.

Mathauser recently sold the manufacturing rights on the design to a
Californian firm which is mass-producing a refined version of the brake.
Richard Gould

Things were pretty relaxed under Old Father Time, even though it wasn’t
always like that – giving his boss a week to make a planet is a pretty tight
schedule. Later in life, when he no longer had a scythe to grind, we had
things easy, as we did during the 1960s. Then his son took over, and TJ
has shown us exactly how he wants to run things.

TJ is young, impatient, obsessed with efficiency and has a penchant
for time-saving gadgets. The verb ‘to wait’ is not in his vocabulary and
he abhors people who are incapable of doing less than three things at once.
His favourite hangouts are editorial offices, computer companies, rush hours
in capital cities, the world’s stock markets and 10 Downing Street. You
will never see him at the post office, Whitehall, the US Immigration Service
or Heathrow Airport. If TJ had his way, these places would be closed.

How can we keep pace with his activities? Fortunately, we can model
his progress with TJ’s law, which I have devised by combining the ideas
of Einstein, Keynes, Newton and Hawking. In its simplest form, it says that
money is related to time squared multiplied by a fudge factor. In real terms,
it means that if you want to make twice as much money, you have to do it
in a quarter of the time. This is fine if you are content to stay put, but
economists are concerned with economic growth. As economies grow, you have
less time to make the same amount of money as you did the year before. Life
gets more frenzied.

Not that this need be a problem: strong coffee and technology save the
day. We simply have to make everything work faster. This phenomenon is most
visible in the computer industry, where the pace is so hot that, if the
staff of a company took a two-week holiday, when they returned to work they
would find that they were six months behind everybody else. This is why
every new computer product is ‘the most advanced product to date’ or ‘years
ahead of the competition’ – they have to be like that so that the poor souls
who developed them can have the occasional lunch break.

However, every reaction has an equal and opposite reaction, so if the
technology gets faster, then something else must give. These days, quicker
gadgets tend to shrink. A case in point is the laptop computer which I’m
using to write this. It’s more powerful, faster and has a bigger memory
than the ‘old’ PC I have in my office, but a fraction of the size. If it
was any smaller then I would have to question its practicality. But TJ’s
Law won’t allow this, which is why we now have real computers scaled down
for teddy bears. If current trends continue, then tomorrow’s computers will
make a Cray look like a forgetful slug and be packaged in a matchbox. No
wonder we need mice to operate them.

Technology changes quickly to hold pace with TJ. Human beings, however,
don’t evolve as fast, and biological functions such as eating now take too
much time. Instant food, microwaves and TV dinners helped a lot in the 1970s
and 1980s, but TJ’s Law seems set to leave them behind. This is where super-fast
food comes to the rescue, and I reckon the US will be the first to develop
this to a fine art. Super-fast food will involve a system of drive-in restaurants,
which will employ telepaths to figure out your order and cook it before
you have even noticed that you are hungry. And when you buy the substances,
you will be able to enjoy them in the comfort of your car, as one accessory
manufacturer has already produced a little table that sits between the two
front seats, and has special places to park your, er, cosmestibles and liquids.

However, the problem with super-fast food is that, in keeping with TJ’s
law, it tends to slow down elsewhere. So the time saved in not having to
prepare food, or even stopping to eat it, may be lost in the smallest room
(is this why laptop computers were invented?). But don’t panic: one friendly
pharmaceutical firm has the answer for those go-getters who want to get
going and, in the words of the laxative manufacturer, ‘don’t have time to
wait’. With friends like that, who needs enemas? So the next time you think
that time is moving at a faster pace, don’t worry: you’re right – it is.
A year is still a year, but it currently takes about six months. And when
your time-saving nano-computers start to disappear without a trace, bear
in mind what physicists have been saying about black holes and the like.
All of this means that the 1990s could be fairly frenetic under TJ, but
I hope that he finishes grinding his scythe before the turn of the century.
Then we can turn the clocks back to the laid-back days of his dad, and look
forward to a more relaxed future.

Richard Gould who lives in Sweden, somehow found the time to write this,
even though the days there are currently just a few hours long.

If I had been born 25 years later, and first saw daylight in the town
of Kungsbacka, in west Sweden, my first taste of fishing would have been
a little different. For some children from this town, the first lesson begins
with a bit of analytical chemistry. The problem with most of the rivers
and streams in west Sweden, such as the River Kungsbacka, is that their
fish have enjoyed better times. Acid rain, which some Swedes regard as Britain’s
major export, has killed most of the trout and salmon. So fishing in Kungsbacka
begins with a simple test to work out the pH of the water, after which follow
some practical lessons in ecology, liming and fish breeding. Once the water
has been limed, and streams and rivers are no longer so acidic, the next
stage is to restock the waters with fish. After several years of continual
liming and some careful monitoring, then, and only then, can the serious
business of fishing begin.

Fortunately, the River Kungsbacka is a success story. In the late 1970s,
the pH of the water had fallen to such a degree that it had lost nearly
all of its sea trout and salmon. Over the years, the local fishing club
watched the situation worsen while governments bickered. By 1984, it was
obvious that emissions of acidic gases were not going to fall sufficiently
to remedy the situation, so the folk of Kungsbacka decided to take some
action. They had among them an aquatic ecologist, Ingemar Alenas. As well
as being nuts about fishing, Alenas has spent most of his career developing
strategies to lime acidified waters, and then restock them with fish. In
1984, Alenasand some of his colleagues applied their professional expertise
to the River Kungsbacka. Now the river has improved so much that the fish
are reproducing in it again. In April this year Alenas’s five-year-old son
had his first lesson in adding trout and salmon fry to the river.

Combating the effects of acidification involves more than simply bunging
a few tonnes of lime into the water. Each lake, river or stream is different.
For example, some lakes have large areas around them which deposit a great
deal of acidified run-off water into the lake, which means that larger amounts
of lime must be added. Other lakes may be low in nutrients, and too much
lime could have undesirable consequences, such as rampant algal growth.
It means that individual strategies must be worked out for each body of
water. Only when the water has reached a stable pH can restocking with fish
begin. Fishing enthusiasts in Sweden have always added fish to the rivers,
but acidification has intensified this effort.

Liming is an expensive business. In the past five years, the Swedish
government has given more than $20 million to projects such as that at Kungsbacka,
and so long as emissions of acid gases are high, the liming must continue.
There are other political problems. The European Community has been very
critical of the liming projects, on the grounds that adding lime to the
lakes and streams will alter the ecosystem. ‘This is true,’ says Alenas,
‘but at the moment liming is the only way to save genetically important
fish stocks from extinction while awaiting reductions in emissions.’ The
new ecosystem (with lime and fish) may differ from the original one, but
it is not as different as one which is acidified and depleted of fish. Many
aquatic ecologists in Sweden feel that the European Community is missing
this point.

Snow complicates the problem: while it is not too difficult to balance
the input of acid rain with continuous liming, it is almost impossible to
combat the problem of acid snow. The problem is that, when the snow melts,
the surge of acidity into the watercan undo years of work. ‘One problem,’says
Alenas, ‘is that the acid surges can kill most of the fish, and there is
no way of predicting where and when all the surges may occur.’

For Alenas, the work continues, but from December he will be able to
devote more time to the ecology of the Kungsbacka district. He will be leaving
his current job with the Swedish Environmental Research Institute in Gothenburg,
having spent 13 years working on liming projects, and will become Kungsbacka’s
first full-time ecologist. Who knows? If he’s lucky, his new job might give
him a little more time to educate his son in the now complicated art of
fishing.

Richard Gould works at IVL, the Swedish Environmental Research Institute,
in Gothenburg.

Planesail is the brainchild of John Walker, an aircraft engineer. His
idea for wingsails came 21 years ago when a motorboat nearly collided with
his yacht and a swinging rope sent him flying. This inspired him to develop
a better system for powering sailing boats.

The wingsail, which looks like a modern aircraft wing, has less drag
and more thrust than conventional sails. As on aeroplanes, the wings have
flaps, air-directing slats, and motorised actuators to move them. The wings
are constructed from epoxy resins on an alloy framework, with the lightly
stressed areas of the wings covered with laminated polyester fabric. Each
wingsail is mounted on the hull by a large ball-bearing, similar to those
found on small cranes.

The skipper can control the actuators either manually, or by a computer
called Micromariner. A network of sensors provides it with information on
the direction and speed of the wind and the boat. It uses this information
to translate a skipper’s commands into signals to the tail and wing flaps.
Micromariner also has a system which warns of any developing faults.

The electric motors for the flaps are powered by batteries. Solar panels,
wind generators and a pair of alternators connected to the auxiliary diesel
engine charge the batteries. The flap actuators can also be moved by hand.
Walker is now working on a boat with more efficient solar panels and electrical
components, so that the diesel engine can be eliminated.

Micromariner can accommodate either semi-automatic or fully automatic
control over the wingsails. In the first case, the computer trims the flaps
according to the sailing conditions but allows the skipper to steer the
boat. Full control is similar to the autopilot used on most aircraft. Walker
believes that his is the first such system to be used for sailing yachts.

Walker and his wife, Jean, set up their company, Walker Wingsail, in
Plymouth in 1983. They hoped to adapt wingsails for larger ships in order
to provide cheap, clean auxiliary power. The first one of these was an enormous
triple-winged device fitted to the 6500-tonne MV Ashington (Technology,
19 June 1986). Although the device reduced both fuel consumption and emissions
of pollutants by 10 per cent, itattracted little interest, as plummetingoil
prices made fuel efficiency less of a priority.

BUSES in Scandinavia are about to start tests on a system that saves some of the energy they lose in stopping, and uses it to start up again. Volvo, the Swedish vehicle manufacturer, is fitting 20 new buses with the device, called Cumulo, for tests in several cities. The company says mass production could start as early as next year.

Volvo’s aerospace division has been developing Cumulo, a hydraulic transmission system, over the past 10 years. The device stores the energy of the spinning driver shaft as it comes to a stop. When the driver is ready to move on, the system reverses the process, returning the energy to the drive shaft.

When a bus half full of passengers brakes to a stop from 45 kilometres per hour, Cumulo captures enough energy to power the bus from standstill to 35 km/h before its diesel engine takes over. It can be fitted to any bus and will dramatically reduce fuel consumption and pollution.

While the bus is moving along at a steady speed, Cumulo remains disconnected from the drive shaft. It is only when the driver applies the brake that an electronic control unit engages the system. At this moment, a clutch connects a heavy gear wheel to the drive shaft. This gear turns a smaller gear wheel that drives a pump, which in turn pushes hydraulic fluid from a reservoir tank to an accumulator.

The accumulator contains pressurised gas. The hydraulic fluid pushes against a plunger, like a bicycle pump, raising the pressure of the gas in the accumulator from 20 million pascals to 36 million pascals. When the bus stops, the electronic control unit closes a valve to contain the pressure.

When the driver steps on the accelerator, the control unit triggers the valve, releasing the plunger. The hydraulic fluid is forced back through the pump, turning the gear wheels and the drive shaft. When the energy is expended, the control unit disengages the clutch and activates the diesel engine, which has been idling during the acceleration.

The transmission system also acts as a hydraulic brake when the bus is slowing down. However, if the bus is descending a long hill and the driver is braking, the control unit prevents the accumulator from overloading by disengaging the system and applying the brakes.

When Volvo began work on the prototypes for Cumulo 10 years ago, it achieved fuel savings of 22 per cent. The savings corresponded to an average of three stops per kilometre of operation. Following this result, Volvo started the second phase of development in 1987.

The second generation of Cumulo is smaller, much lighter, and according to Sverre Skauby of Volvo, ‘hopefully much more reliable’. Skauby claims that the improvement in fuel consumption could be as much as 30 per cent. Cumulo also prolongs the lives of the engine and brakes. Initially, Cumulo will be available only for buses, although Lars Scharland, the project manager, has said that it could be developed for other applications in the future.

Another benefit is a reduction in the amount of soot emitted from the diesel engine. Exhaust gases from diesel engines contain hydrocarbons that may cause cancer. These compounds bind to the soot particles, making them easy to breathe in.

A diesel engine gives off the greatest amounts of soot when the bus is accelerating, for instance away from a bus stop, where people are most exposed to the fumes. The Cumulo transmission largely eliminates these, because the engine is only idling while the hydraulic accumulator provides the driving force.