WHAT skims just metres above the water, looks like a plane, but can be
flown by anyone with a speedboat licence? The answer is the next generation of
flying boats, called wing-in-ground effect craft. The race is on to be the first
to produce a commercial WIG. Teams in Russia, China, the US and Germany have
been designing WIGs. But two teams from Australia hope to pull ahead of the pack
with the launch of prototypes this month.

WIGs are designed to fly above the water at a height of no more than 5
metres. At this height, they take advantage of the wing-in-ground effect,
which is an increase in the ratio of lift to drag for a wing flying close to the
underlying surface. Experiencing 70 per cent less drag than a normal plane in
flight, the craft can travel farther on less fuel than a conventional plane,
helicopter or boat.

Rada Corporation of Melbourne has designed a two-seater vessel called
Radacraft. This prototype, with a wing span of 6.5 metres, can fly up to three
metres above the water and reach a top speed of 120 kilometres per hour. The
Rada team also plans to build a larger craft that will carry eight people and
reach speeds of up to 180 kilometres per hour.

In Tasmania, Sea Wing International is developing a five-tonne four-seater
prototype. With a 10-metre wing span, Sea Wing will cruise five metres above the
water at 120 kilometres per hour. John Lesley, who designed Sea Wing, says it
could provide a squadron of cheap patrol craft to protect Australia’s vast
coastal waters. “Sea Wing could skip across the reefs and shallow tidal flats to
land beside a smuggler’s boat faster, easier and cheaper,” says Lesley. By
October, he plans to build a five-tonne craft to carry up to 17 people.

All WIGs fall into one of three design categories—the Lippisch, the
Ekranoplan and the Jörg—each with a different wing shape. The
Ekranoplan has a short, broad wing, the Lippisch craft has a triangular wing
with the point facing towards the tail and the Jörg model has a pair of
wings in tandem, with one behind the other. Rada used the Ekranoplan design,
while Sea Wing opted for the Lippisch.

Lawrence Doctors, head of naval architecture at The University of New South
Wales, says: “The critical test for these craft will be whether they can fly at
several metres above the water and still remain in the zone where wind drag is
łľľ±˛Ôľ±łľ˛ą±ô.”

The Russians began experimenting with WIGs in the 1960s and built some of the
largest Ekranoplans. But these giant military craft are a far cry from the nippy
little prototypes now under development.

Paul Sacco and his colleagues at the Australian Neuromuscular Research Institute in Perth studied seven top badminton players and seven people matched for age and sex who did not regularly play the game. Badminton players send the shuttlecock speeding over the net with a sharp flick of the wrist. This is achieved by contracting the wrist flexor muscle, which runs down the forearm from the crook of the elbow.

The researchers recorded the electrical activity of the volunteers’ brains as they played. From these recordings they mapped which of 32 different areas within the brain’s motor cortex were active when a stroke was played. In both groups, the strongest activity occurred in the same brain areas. But the activity of the top players’ brains was more focused: larger areas of their motor cortex remained silent each time they struck the shuttlecock.

“Our whole motor system is ready to go, but with the pause button on,” says Sacco. “All that is needed to move a muscle is to release the pause button and the neurons fire.” When average badminton players flex their wrists during a stroke, Sacco believes, a number of muscles are recruited to generate the movement. But skilled players seem to have a more selective pause button and so can use the wrist flexor muscle exclusively.

“It’s not the case that you need more brain power to do a certain skilful movement,” Sacco concludes. “What’s critical is the balance between neuron excitation and inhibition.”

David Wilcken and his team at the Prince Henry Hospital in Sydney, have studied more than 20 different genes which could increase the risk of heart disease, such as those affecting blood cholesterol levels and clotting. They looked at the gene that codes for the NO enzyme because the dissolved gas relaxes blood vessels, keeping them open and allowing free flow of blood. The gene sits on the long arm of chromosome 7, and about 7 per cent of the population carry the dangerous form.

The researchers took DNA samples from 550 patients who had complained of chest pains. They knew the smoking history of each patient and correlated this with the occurrence of the rare gene and the severity of the blocked blood vessels. The gene was directly related to the severity of heart disease among the smokers, but had no obvious ill effects in the nonsmoking patients (Nature Medicine, vol 2, p 41).

While the research shows that genetic factors can exacerbate the damage done by unhealthy habits, Wilcken stresses that “good” genes can never make smoking safe. “This does not give a licence to smoke to those people without the rare gene,” he warns. “Everyone who smokes is susceptible to heart disease, but your chances are increased if you carry this genetic marker.”

“It’s the first few minutes of falling asleep when the body’s reactions are changing quickly that are the most dangerous,” says Richard Upton, head of the University of Adelaide and the Royal Adelaide Hospital team which developed the software.

The body’s level of consciousness must be precisely controlled to balance the level of stress inflicted by surgery. If the anaesthetic is too light then procedures such as inserting a tube down a patient’s throat can stimulate the release of adrenaline and cause their blood pressure to rise. Too much anaesthetic sends the blood pressure tumbling to dangerously low levels.

For the past three years the group has measured the flow rate and concentration of anaesthetic drugs to sheep’s brains and hearts. They used these data to design mathematical models to mimic physiology, and they can now predict how these drugs will move in and out of the brain under various conditions. The resulting software controls a pump which operates the speed of the syringe plunger.

“This system will give us more time to monitor the patient,” says Guy Ludbrook, an anaesthetist with the University of Adelaide. Clinical trials of the syringe system are scheduled to begin at the Royal Adelaide Hospital next year.

The aircraft are called aerosondes. They were designed by Perkins Engineering of Melbourne, the Australian Bureau of Meteorology and The Insitu Group of Washington state. An aerosonde is cheaper than current methods of monitoring the weather and provides better coverage. Remote areas such as oceans are not covered by weather balloons, and it is expensive and dangerous for large planes to fly into storms. Remote sensing satellites may have global coverage but have poor vertical resolution – when watching from orbit it is difficult to work out the height of weather features.

“The aerosonde can navigate into the eye of a storm, monitoring changes as it flies along,” says Greg Holland, from the Bureau of Meteorological Research Centre in Melbourne. Last week the design partners sent an aerosonde on its maiden flight into a thunderstorm over the Tiwi Islands, 25 kilometres off the north coast of Australia.

Three aerosondes are now due to fly several 24-hour missions to record the evolution of thunderstorms as part of an international project called the Maritime Continent Thunderstorm Experiment. The storms build up over each island every afternoon during November and December. There are between 30 000 and 40 000 islands in this region, which covers Indonesia, the Philippines, Malaysia and Papua New Guinea. According to Holland, the convective storms sitting above each island have a huge cumulative effect on the regional and global climate.

The plane is 1.6 metres long and has a wingspan of 3 metres. One of the two on-board computers controls the flight path and monitors the mechanics and fuel and oil levels during the journey. The other computer controls the meteorological instruments which record changes in the temperature, humidity, pressure and wind. The aerosonde navigates using the Global Positioning System, which can determine its position to within 30 or 40 metres. For take-off, the aircraft is strapped to a car roof rack. All that is needed is about 1.5 kilometres of flat ground for the car to drive along. When the car is travelling at about 50 kilometres an hour the wings of the plane start to lift and the strap falls away.

The aircraft weighs 15 kilograms with a full load of fuel. It can fly for 7000 kilometres on a single 10-litre tank. “At the moment it can reach an altitude of 5 kilometres, but eventually we hope it will go up to 16 kilometres,” says Holland. But before this can happen, a turbo charger must be designed to compress the air in the engine so that it can run efficiently at the lower air density.

Even at relatively low altitudes, aerosondes are in danger of icing up. The computer is programmed to direct the plane to descend when ice is detected on the wings. This should allow any ice to melt. If the air intake and carburettor ice up then the engine will stop and the aircraft will glide to the ground.

Just in case any of the aircraft are lost, 11 aerosondes have been shipped to the Tiwi Islands. Each plane costs around A$22 000, but they are still cheaper to use than a regular aircraft used in tropical cyclone research, which costs between A$7000 and A$10 000 an hour to fly.

Decades of irrigation and deforestation have swelled the reserves of water lying under much of Australia’s farmland. And as the water rises, it carries salt to the surface. Already, 2 million hectares have been degraded by salinity, according to the Murray-Darling Basin Commission – the government body looking at the problem. Salt damage costs the country A$200 million (ÂŁ100 million) a year in lost production, according to the government (“Australia’s growing disaster”, New ĐÓ°ÉÔ­´´, 29 July 1995).

The new salt detection system is called Saltmap. It was designed by World Geoscience Corporation (WGC) in Perth, the Cooperative Research Centre for Australian Mineral Exploration Technology, and the CSIRO, Australia’s national research organisation. The system is adapted from metal detectors used by geologists to hunt for ore deposits. Like the metal detectors, Saltmap generates electromagnetic fields and picks up a response from the ground.

An alternating current passes through a copper cable strung around the body of the plane. This generates a pulsating electromagnetic field which induces secondary electrical currents in the ground wherever there is a good conductor, such as saltwater.

This secondary field is measured by a torpedo-shaped antenna, which trails behind the aircraft. Data from the antenna are analysed by an onboard computer. The size of the induced current indicates the concentration of salt, while shallower salty layers return signals more rapidly and contain more higher-frequency components. With one flyby, the system can detect saline water lying between 5 and 30 metres underground.

The idea of an airborne salt detector is not new, but Guy Roberts of WGC says that Saltmap provides more detail than earlier systems. “We can see at shallower depths and discriminate several layers of water,” he says.

According to Lindsay Nothrop, director of government’s Community Landcare Initiatives, the technique works best when surveying relatively flat areas. This is the kind of terrain where salinity most often causes a problem. “Although the system is not applicable everywhere, it’s still a cheap reconnaissance tool to find saline hot spots in many areas,” says Nothrop. (see Diagram)

ĐÓ°ÉÔ­´´s estimate that there are now some 300 million rabbits in Australia. The government claims that they are responsible for eating pasture and crops worth about A$90 million (ÂŁ44 million) a year.

In 1950 the government introduced the deadly myxoma virus to control rabbits. Since then, many rabbit populations have grown resistant to the disease and in some places as many as 70 per cent of rabbits survive infection. Trapping, shooting and poisoning work only in small areas.

Vaccinating rabbits to stop them breeding could be the answer to the resistance problem, said Tony Robinson, head of a team at the Cooperatve Research Centre for Biological Control of Vertebrate Pests. He told the ANZAAS meeting that his group has created a myxoma virus that contains a gene for a protein on the surface of sperm, and another that includes a gene for a protein found in the coating of eggs. Rabbits infected with these viruses would produce antibodies against sperm or eggs.

The group now wants to find out if the rabbits’ immune response will be strong enough to make them infertile. The researchers have permission from the government’s Genetic Manipulation Advisory Committee to test its altered viruses in the lab.

For the strategy to work, Robinson’s group needs a strain of myxoma that will infect as many rabbits as possible. So they are looking for a mild strain that does not kill, and so will linger in the population. Last week, a candidate strain was released in the Cooma district south of Canberra to assess how well it spreads. “If this works, then the net suffering of rabbits will be reduced because there will be fewer animals to be shot, poisoned or infected with a virulent strain of myxoma virus,” says Robinson.

Animal welfare groups are cautiously optimistic about the idea. “Overall I’m very pleased that fertility control of feral animals may be a reality, but we should strive to make it humane,” says Glenys Oogjes, director of the Australian and New Zealand Federation of Animal Societies. But like others she is concerned about the use of the myxoma virus to carry the vaccine. Virulent strains of myxoma produce painful lesions: the rabbits eventually go blind and starve or are easy prey for foxes and cats.

Others express outright opposition to using a genetically engineered virus to keep rabbits down. It is an unnecessarily risky strategy, says Glenn Albrecht, an environmental scientist at the University of Newcastle. Introducing a new “disease” which makes animals infertile may not work – and it could infect other species, he says.

Robinson argues that there is no great risk of myxoma infecting other species. It is “one of the most species-specific viruses that we know”, he said.

But Albrecht’s objections go deeper, as he disagrees with the whole idea of trying to eradicate feral animals. Even though rabbits came from Europe, he says, they are now part of the Australian ecosystem. He thinks threatened native species would be better protected by expanding areas of natural habitat and controlling feral animals with conventional methods.

This tolerant attitude to imported pests would be unlikely to go down well in New Zealand. Most people there would like to see the country rid of possums by any means, the ANZAAS meeting heard. Phil Cowan from Landcare Research, a state-owned research agency in Palmerston North, said that 73 per cent of people questioned in a recent survey wanted the possums exterminated and 85 per cent agreed with using contraceptive methods to achieve this. Brushtail possums were imported from Australia, and with no natural predators, their numbers have soared to around 70 million.

Researchers from AgResearch, the state-owned research agency, are confident that a virus is at work, because tissue remained infectious even after it had been passed through a series of fine filters. “A virus is the only thing that could have got through the rigorous filtering process,” says Paul Atkinson, of the animal division of AgResearch in Wallaceville.

The first cases of “wobbly possum syndrome” appeared among laboratory animals in mid-February. Almost immediately, reports started coming in from farmers who found animals staggering around on the ground during the day -unusual behaviour for a nocturnal animal which lives and feeds in trees. The virus progressively destroys the possum’s balance and eyesight so that it becomes increasingly difficult for the animal to feed.

Possums are a serious pest in New Zealand, and the researchers think the virus could provide a means of controlling their numbers. The possum, imported from Australia to start up a fur industry in the 1830s, has no natural predators and its numbers have now reached around 70 million. They pose a grave threat to the country’s native vegetation. Paul Livingstone from the Animal Health Board in Wellington, estimates that each night the possums eat their way through 21 tonnes of native trees and pastures. The possums also carry bovine tuberculosis, making them a threat to the country’s beef and dairy industries.

Attempts to reduce the possum population by dropping poisoned bait from the air or trapping and shooting them have failed. “The virus has the potential to be used as a biological control agent,” says Colin Mackintosh, a research vet with AgResearch at Invermay. “The big advantage is that it’s a naturally occurring agent, so we are not introducing something from outside,” he says.

The next step is to find out what it is and whether it poses a danger to other species. “We need to identify the virus, and find out whether it affects possums only,” says Atkinson.

The battery was designed by engineers and electrochemists at the University of New South Wales in Sydney. Like other batteries it relies on electrically conducting solutions called electrolytes. But the new battery has two electrolytes containing different solutions of vanadium sulphate and dilute sulphuric acid.

When the solutions are spent, they can be pumped out and replaced. They can be recharged at the service station and made ready for the next driver who needs to fill up.

The researchers have already developed a golf cart that is driven by the new battery. “We can demonstrate that the battery works,” says Maria Skyllas-Kazacos, who heads the research team. “But at the moment it’s too big to be used in cars. We need to reduce the size of the storage tanks holding the electrolyte.”

At the moment, the battery needs two 280-litre storage tanks. This is fine for a bus or lorry, but not for the average family car. The team is working on reducing the tank size, by doubling the concentration of vanadium in the electrolyte solutions. According to Skyllass-Kazacos, this would provide enough energy to run an electric vehicle for 160 kilometres.

The battery is called a vanadium redox flow battery. It has two tanks holding the vanadium solutions, which are linked to a stack of battery cells by two small pumps. The pumps replace spent solutions in the stack, for example, when the vehicle needs extra power to accelerate up hill. The researchers say that around 5 per cent of the energy from the battery goes on powering the pumps.

The device uses vanadium ions in four different oxidation states. Each type of ion has a different amount of positive charge. When the battery is fully charged, one tank contains a solution of vanadium ions, each with five positive charges (vanadium V), while the other tank contains vanadium ions with just two charges (vanadium II). When connected, the potential difference between the two solutions drives electrons from one to the other, generating a current to power the vehicle.

Although the solutions are physically separate, electrons can flow between them through a bipolar plastic electrode that divides them. Once the exchange is complete, the vanadium V ions have gained one electron each to become vanadium IV ions, while the ions in the vanadium II solution have each lost an electron to leave a solution of vanadium III ions. At this point, the battery is flat and the electroIytes must be recharged or replaced.

When fully charged, each cell can generate a potential of about 1.5 volts. The cells can be stacked to give larger voltages. The amount of energy stored depends on how much vanadium is in the electrolytes, which can be increased or decreased by changing the size of the tanks or the concentration of the solutions.

Skyllas-Kazacos says the battery is safer than other batteries because it works at ambient temperatures. Batteries tend to heat up as they are recharged, but in this case, the electrolytes act as coolants.

The university has already granted two commercial licences for non-vehicle applications of the new battery. Thai Gypsum Products in Thailand is beginning trials of the batteries to provide back-up power for solar houses in remote areas, and a Japanese consortium is developing a 300-kilowatt version to provide energy to the grid at times of peak demand in the Tokyo area. The consortium eventually plans to have several megawatts of battery power available.

Jim Peterson of Monash University in Melbourne and Geoff Hope of the Australian National University in Canberra have been studying three of the four equatorial glaciers on the summit of Mount Jaya in lrian Jaya, the Indonesian portion of the island of New Guinea.

The three glaciers – Meren, Northwall Firn and Carstensz – were first recorded by explorers in 1936. From this starting point, Peterson and Hope used historical records coupled with data from recent visits to Mount Jaya to measure how far the ice had retreated. They compared aerial photos of the glaciers taken in 1936 and maps drawn in 1962 with their own surveys conducted in 1971, 1993 and 1994. Since 1936, the glaciers have shrunk by some 16 square kilometres, and today less than 3 square kilometres of ice is left. The rate at which the glaciers are receding also seems to have accelerated, from about 30 metres per year at the time of their discovery to the current rate of 45 metres a year.

The researchers say that the Meren glacier may soon be defunct. Last year, Peterson and Hope returned to find that it was cut off from its supply of ice. “What is left is a chunk of ice that is completely out of place,” says Peterson. “It is not being renourished so when the last of it melts it will completely disappear.” Global warming is the most likely culprit, say the researchers, as the glacial retreat does not seem to be due to a decrease in precipitation. “This region has heavy snow showers,” says Hope. “So the shrinking must be due to a rise in temperature.”

A paper on the demise of Indonesia’s glaciers will be published in a future issue of the journal Zeitschrift für Gletscher kunde und Glazialgeologie.