A THREE-DIMENSIONAL (3D) printer powered by sunlight has been developed with the aim of turning desert sand into glass. Now, experts are recognising the device as a promising first step towards a future large-scale industry. The machine, developed by German designer Markus Kayser, is called the Solar Sinter. It takes its name from both its energy source and the technique it harnesses — sintering — which converts a powdery substance into a solid form by heating. 3D printers use laser technology to create precise solid shapes from a variety of powdered metals, plastics and resins. Its most common use is in creating prototypes for engineering projects. Kayser’s device replaces the laser with the sun’s rays and the powdered material with common desert sand. He believes it could be used to exploit the largely untapped natural resources of deserts in the Middle East and North Africa. The Solar Sinter uses a large Fresnel lens, which is designed to capture the same amount of light as conventional lenses but is lighter and thinner. The lens rotates towards the sun throughout the day to capture light, which melts together layers of sand contained within the device to produce glass objects. Digital designs can be downloaded from a computer onto a simple memory card and transferred to the machine. The Solar Sinter then follows the models’ ‘instructions’ and prints out 3D reproductions of the designs. Kayser, who developed the Solar Sinter in 2010 during his studies at the Royal College of Arts in the United Kingdom, says that in the future the process could become the most cost-effective way of producing glass, because solar energy and sand are abundant and free, and large-scale factories could be built in the desert. The lens costs about US$600, making it cheaper than most of the parabolic devices used to capture light in the desert, says Kayser. Eventually the process could produce a variety of artefacts ranging from glass vessels to the surfaces for photovoltaic panels. “I would really love to see companies using or developing this process into a business,” he says. “Many ideas remain stuck in university, but it would be nice if the Solar Sinter concept became a commercially viable process as, in the end, it’s free and clean energy.” A ceramics company interested in the Solar Sinter’s applications sponsored one of Kayser’s latest research trips to the Moroccan desert, which he believes is a positive sign. Robert Jeffreys, a 3D printing consultant at the UK-based company Inition, says: “There is potential in the idea of machinery that can use what is already on location, to produce things. I think [the Solar Sinter] would be useful in places where the raw material is in great supply but is inadequate for most conventional manufacturing.” In the future, says Jeffreys, 3D printing could become advanced enough to produce high-quality objects, and the Solar Sinter could be the first step towards this long-term goal. “3D printing is now raising an exceptional interest from the media,” he adds. “Popularity could attract funders and speed up the research.” Jeffreys says that one of the major problems in the 3D printing industry worldwide is the high cost of materials: “Research centres and universities in developing countries often have a 3D printer but they rarely use it because they can’t afford the specific plastics. Having free materials would probably make the difference.” (SciDev)
Focus on local crops as farming intensifies
THE PRESERVATION of genetically diverse local crops can be compatible with the intensification of small-scale farming, a study in Latin America has found. The conservation of agricultural biodiversity can be combined with agricultural development to increase the income of small-scale farmers, according to the study, which examined parts of Bolivia where the cultivation of peaches and other non-traditional crops has recently expanded. Previous studies suggested that intensification based on non-traditional crops was incompatible with the agrobiodiversity conservation of local crops such as maize, because they could not or were unlikely to co-exist. These new findings show that they can be grown together under certain conditions. The study is part of a ten-year project, currently in its fourth year, investigating maize and fruit agriculture in Bolivia, Mexico and Peru. “In general, these Latin American countries are extremely important [as they have a] globally unique and high-priority agricultural biodiversity of maize, while requiring agricultural intensification and development to benefit the rural poor,” says Karl Zimmerer, head of the geography department at Penn State University, United States, and head of the project. The Bolivian study analysed 174 small-scale farms in three areas within Bolivia’s Valle Alto region. Zimmerer and his colleagues surveyed land use to assess crop production, while interviews with farmers and officials enabled the identification of some of the factors that encourage and enable local farmers to keep growing wild maize while practising intensive agriculture on peaches. He says that the following factors are important: farmers prefer to eat maize, they earn enough so they can afford to not fully intensify their farms, they have sufficient knowledge on land management and know how to obtain better crops; they have the capacity for innovation so they can grow both peaches and maize, and they use money earned to further improve their farms by investing in seeds and agricultural products. Zimmerer adds: “It is specific combinations of these factors that lead to favourable outcomes for conserving high-agrobiodiversity maize. While these factors are region-specific, they are also found elsewhere, so what has worked in Bolivia could work in other developing countries”. Hugo Perales, head of the agroecology department at El Colegio de la Frontera Sur, Mexico, says the study shows that the relationship between the intensification of farming and preservation of crop biodiversity is not straightforward. The presumption that more intensive agriculture leads to more development but less biodiversity may be flawed, he says. The larger project of which the Bolivian research is a part seeks to examine the relationship between biodiversity and farming on other continents, especially Africa and Asia. The aim is to establish a global network of sites for research and livelihood analysis, which examines how people make a living through farming and other means. (SciDev)
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