Something fishy in the wadi
Scientists at the Jacob Blaustein Institute for Desert Research at Sde Boker are developing modern technologies that exploit the desert climate for the benefit of man
A ray of sunshine
Laser surgery has become increasingly common in recent years. Lasers are used to remove cancerous growths, to cut tissue and even to whiten teeth and to remove unwanted hair. A team of physicists from the Blaustein Institute for Desert Research [BIDR] at Sde Boker proposes performing similar operations exploiting the Negev's main resource - sunlight - for medical purposes.
"Until now we have used solar energy for heating water, but this is energy in every sense, which can be exploited for many purposes," explains Prof. Jeffrey Gordon of the Department of Energy and Environmental Physics at BIDR.
A team of scientists has invented a special instrument that absorbs the sunlight. Immediately afterward another instrument, which was also developed at the institute, filters the solar energy. From this moment on, the process is similar to ordinary laser surgery - the concentrated sunlight is delivered with high intensity to the area being operated on. In experiments conducted to date, doctors have succeeded in removing cancerous growths and cutting tissue using this method.
According to Gordon, solar surgery is 100 times cheaper than that performed with laser beams. The intensity of the sunlight is also greater than that of the ordinary laser, which makes it possible to achieve better results. In the experiments, the medical team successfully operated on animal livers, and removed malignant growths with great precision. Soon the institute is planning to begin experiments on live animals, and if funding is found for the project, they will be able to begin tests on humans.
The only disadvantage of solar energy that the researchers have encountered so far is the dependence on the weather. Since it is impossible to store sunlight, solar surgery can be performed only on sunny days, and in areas where there are large amounts of sunshine. Even too much dust in the air is liable to reduce the intensity of the medical instruments. But Gordon says, "Even now, many laser operations are postponed due to technical problems, usually nothing will happen if the operation is postponed for a week. Therefore, if it rains, one can simply tell the patient: `Come back next Wednesday.'"
Window of opportunity
The desert climate encourages researchers to develop unique construction technologies, suitable for life in harsh conditions. Thus, for example, scientists have to make sure that the buildings they construct will be cool in the summer and warm in the winter. In addition, they are expected to deal with the severe shortage of water. One of their inventions is a "desert window" which is now being developed at BIDR in Sde Boker.
At first glance, the desert window looks like a very complex invention. It is in fact similar to the simple home window, but they are as different as a Volkswagen Beetle and a racing car.
The new window is composed of dark glass and ordinary glass, with a space between them. During the summer months, the dark glass faces the outside of the house; the sun's rays hit the glass and the glass neutralizes them. The space between the two types of glass causes the hot air to leave the area of the "desert window" and cooler air to enter it. This action prevents the heating of the ordinary glass, and leads to a lowering of the temperature inside the house. In addition, the entire mechanism prevents harmful solar radiation from penetrating the house.
In the winter, the dark glass is placed inside the house, where an opposite action allows the desert window to raise the temperature inside the house. It also prevents the penetration of dangerous radiation.
Scientists believe that the cost of the desert window will be only about 20 percent higher than that of an ordinary window. The use of this window, says Dr. Yair Etzion, head of the Man in the Desert department at the institute, would substantially reduce the use of electricity during both the summer and the winter months. The amount of electricity saved would subsidize the cost of the window, and indirectly, reduce air pollution.
The desert window project has been developed so far with the help of the European Union, and Etzion currently is conducting negotiations with foreign companies to begin producing and marketing the unique window.
For 14 years, Dr. Samuel Appelbaum has been trying to convince politicians, investors and Negev residents that the Israeli desert is a particularly good place for raising fish. "In Israel fish have always been raised only in the north," says Appelbaum, head of the Center for Desert Aquaculture, somewhat bitterly.
"Because the Mediterranean is too stormy, fish cannot be raised on the coastal plain. In Eilat they prefer tourism to fish breeding. The north is faced with a constant shortage of potable water. So why not raise fish here in the Negev?"
When Appelbaum proudly displays the 10 aquariums standing in his laboratory in the heart of the desert, one can understand that this is not a hopeless vision. Despite the dry climate, there are huge quantities of subterranean water in the Negev. Because of its high salinity, this water cannot be used for drinking, but it is very suitable for raising fish.
"At present we are using the water reservoirs in the Negev only for agriculture. Very few crops can grow on saline water, but many of the fish actually prefer it," explains Appelbaum.
The water in the Negev has other significant advantages, he points out. It remains at a fixed temperature of 40 degrees Celsius all year long, so there are savings in heating costs. In addition, because it has never been used, and because it is located in the heart of the desert, the Negev water is not polluted.
The consumption of fish and seafood worldwide has been growing at a dizzying rate from year to year. Every Israeli eats an average 11 kilograms of fish per year, and the growers expect a significant increase in demand in the coming decade. The local production of fish no longer supplies the needs of the population, so Israel is forced to import fish. This idea could change the trend.
Fish and shrimp currently are being raised at BIDR and in nearby moshavim using Appelbaum's technology. Most of the fish are exported. The shrimps, which are much in demand in Europe, have acclimated extremely well in the Negev. Now at Sde Boker they are trying to raise the Australian barramundi fish. The meat of this fish is considered especially tasty, but it cannot be raised in the north of the country because it is a carnivore. If it can acclimate to the Negev, the barramundi will also become one of Israel's export industries.
Stuck in the mud
An intriguing initiative that has been examined at BIDR is the construction of homes from mud. Members of the Man in the Desert department have tried to build houses based on muddy soil. The scientists believe the construction of mud houses is cost-efficient and effective. In a desert area it's easy to get such soil, and according to the study, a house built from mud is much cheaper than concrete or wooden houses, and is also earthquake-proof.
Dr. Yair Etzion, who headed the project, says that mud houses are also more suited to a desert climate. "These houses heat up much less in the summer, and cool off less on winter days. Our goal was to develop new technologies that would make it possible to adapt residential buildings to the harsh desert climate, with a minimum of external investment."
But despite the many advantages, and although the efficiency of the mud houses has been proved in tests, the experiment has been shelved. The Israeli authorities did not express interest in such houses, and since the institute couldn't find resources for continuing the research so the houses could be marketed abroad, the BIDR decided to discontinue the project.
"We wanted to sell these houses to India, South America and Africa," says Etzion. "But since we didn't succeed in doing so, we have begun to develop other technologies suitable to life in the desert." n
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