Some use it to grow bones. Others to build planes. The American talk show host Jay Leno used it to replace the rusty bits of his 1907 White Steamer automobile, one of his vast collection of old cars. Hardly a week goes by without headlines about 3D printing, a technology that’s going to change the way you live. Welcome to the next industrial revolution.
The first industrial revolution boosted the income of hoi polloi and reshaped society over decades as manual labour was displaced by machine-based manufacturing. Factories produced items in their thousands and tens of thousands to enjoy vast economies of scale. Today, however, bespoke craftsmanship is making a comeback, thanks to 3D printing or “additive manufacturing”, in which a three-dimensional object is built layer by layer.
As a manufacturing process, 3D printing contrasts with the traditional “subtractive” approach, which relies on milling, grinding and cutting to remove material, wasting much of it in the process. This creative development offers all kinds of advantages and innovations.
The company 3T RPD, of Greenham Common, Berkshire, working in partnership with the University of Southampton, has created an Unmanned Aerial Vehicle; Plastic Mould the world’s first 3D-printed aircraft. At Loughborough University, Richard Buswell is developing a vast, three-storey rig to create buildings by ''concrete printing’’.
Susmita Bose and colleagues at Washington State University recently described in the journal Dental Materials how they used a customised printer to create a bone-like material that can be used in orthopaedic operations and dental work. Other researchers are laying down layers of living cells. And a new generation of edible objects is being printed by Peter Walters at the University of the West of England. Scientists can reconstruct fossil bones, clone priceless artefacts and forge body parts.
Why stock warehouses with parts from abroad when entire designs can now be stored in virtual computer warehouses, waiting to be printed locally, and on demand? So asks a Science Museum curator, Ben Russell, who has used 3D printing at University College London to recreate the contents of a delicate plaster mould that turned out to be a lost bust of the Scottish engineer James Watt. He says 3D printing is an organic blend of craft and hi-tech that is a million miles from the production line assembly methods pioneered by Henry Ford.
The idea is not new: 3D printers have been available commercially for three decades, and are routinely used to make prototypes by car manufacturers. I first become aware of the potential of what was then called “rapid prototyping” in 2004, when I visited the Renault F1 team works in Oxfordshire, where titanium and plastic components were solidified from a soup of ingredients scanned by a beam of blue laser light.
But what has changed is that 3D printers are becoming cheaper, smarter, better and more ubiquitous. One of the more remarkable developments came from Adrian Bowyer of the University of Bath, with RepRap, which stands for ''replicating rapid-prototyper”, on which I reported for this paper. RepRap had first been honed to print out everyday plastic goods such as door handles, sandals and coat hooks. The machine works like a printer but, rather than squirting ink on to paper, it puts down thin layers of molten biodegradable plastic which solidify to make objects.
Three years ago, however, the machine had succeeded in copying all of its own 3D-printed parts, which could be assembled into a new RepRap machine.
RepRap marked the birth of a domestic machine, a revolution analogous to that which saw the mainframe computer give way to the desktop PC. Recently it became available in kit form and Bowyer has already sold 100. All the while, the software and other ingredients are getting cheaper. There are rival kits, from Bits from Bytes to MakerBot. There are hackers adapting and improving them. As the technology mutates and evolves, the quality of the objects they can make gets better.
2011年12月6日星期二
2011年9月25日星期日
Try a new, improved strawberry
This is the perfect time to start planning so that your strawberry crop next year is the best ever.
If you have a strawberry bed, tidy it up in the next month or so. Untidy beds are at greater risk of disease, which will affect cropping next year. Look out for any signs of virus and assess whether plants need replacing. The widest range of varieties is available in October so you can choose the best for flavour and performance.
Commercial strawberry producers have developed many new varieties and growing techniques that have benefits for home gardeners too.
You can grow fruit over a longer season, with excellent flavour and disease-resistance. You can also obtain better yields from less space, reduce the need for fungicides and use less water.
he best thing about growing your own strawberries is that you can pick them fresh, at just the right stage of ripeness when they are juicy, with a sweet flavour and aroma – qualities that change within a day of picking.
You can also seek out varieties that the supermarkets do not stock. 'Sallybright’, a British-bred variety listed by Dobies and Suttons, is a tasty early variety, but the berries are too fragile for supermarkets.
'Malwina’ is a juicy, flavoursome late berry but is deemed too dark a red to sell well in supermarkets. Fortunately, most mail order fruit specialists are listing it. Both are Which? Gardening best buys for flavour, but you can only get them if you buy runners this autumn.
The Which? survey (June 2011) also recommended 'Darlisette’, 'Elsanta’ and 'Sonata’. This summer, as part of a Thompson & Morgan blind taste test, I sampled six new varieties. My two favourites were 'Sweetheart’ for its peardrop flavour and 'Cupid’ for being extra sweet and juicy.
British growers now supply supermarkets with fresh strawberries from April to October, so if you finish picking strawberries in three weeks, consider extending your season by growing an early, mid and late variety.
Another good reason for trying new varieties is that they offer higher yields. R W Walpole is a family firm who have been growing strawberries in Norfolk since 1926, yet Paul Walpole is in no doubt that new varieties are higher yielding: “Old favourites such as 'Royal Sovereign’ or 'Cambridge Favourite’ produce 7oz and 12oz of fruit per plant respectively, but it is easy to find modern varieties that give 1½lb-2lb 3oz per plant,” he says.
When it comes to fruit quality, heavy rain, careless watering or wet soils can spoil the fruit and spread diseases such as grey mould (Botrytis), which makes fruits inedible. For high rainfall areas, Paul recommends varieties with waxy berries such as 'Fenella’ and 'Elegance’. 'Cupid’ is disease resistant, and also rain-tolerant, as its leaves protect the fruits.
Infection can often be traced back to planting too close or the flowers getting too wet. To prevent grey mould, always direct water at the surface of the soil, so the flowers are not wetted. When heavy rain is forecast, a temporary cover of perforated polythene will help.
Straw suppresses weeds and protects the ripening fruit from rot. However, it is vital to wait until there is very little risk of frost before laying straw.
Too early and you will only succeed in making the flowers more vulnerable to frost: the straw acts as a barrier between them and the insulating effect of the soil.
Tabletop growing is a commercial technique that uses growing bags raised off the ground and fitted with automatic watering. This gives growers more control over the crop, and uses less space. It also means they don’t need to sterilise the soil and there is better air circulation around the crop, meaning less disease. The watering and feeding is very precise, hence less waste of resources and less feed leaching into the water table. Picking the fruit is also easier, as is weed control.
For home gardeners, the ability to get more out of a small space, better quality fruit and ease of picking are all advantages that can be copied. Use eight to 10 plants per bag, and support them on a couple of upturned packing crates. Cut a plastic water bottle in half and insert it into the compost upside down. Give a regular dose of liquid tomato feed containing seaweed extract.
If you have a strawberry bed, tidy it up in the next month or so. Untidy beds are at greater risk of disease, which will affect cropping next year. Look out for any signs of virus and assess whether plants need replacing. The widest range of varieties is available in October so you can choose the best for flavour and performance.
Commercial strawberry producers have developed many new varieties and growing techniques that have benefits for home gardeners too.
You can grow fruit over a longer season, with excellent flavour and disease-resistance. You can also obtain better yields from less space, reduce the need for fungicides and use less water.
he best thing about growing your own strawberries is that you can pick them fresh, at just the right stage of ripeness when they are juicy, with a sweet flavour and aroma – qualities that change within a day of picking.
You can also seek out varieties that the supermarkets do not stock. 'Sallybright’, a British-bred variety listed by Dobies and Suttons, is a tasty early variety, but the berries are too fragile for supermarkets.
'Malwina’ is a juicy, flavoursome late berry but is deemed too dark a red to sell well in supermarkets. Fortunately, most mail order fruit specialists are listing it. Both are Which? Gardening best buys for flavour, but you can only get them if you buy runners this autumn.
The Which? survey (June 2011) also recommended 'Darlisette’, 'Elsanta’ and 'Sonata’. This summer, as part of a Thompson & Morgan blind taste test, I sampled six new varieties. My two favourites were 'Sweetheart’ for its peardrop flavour and 'Cupid’ for being extra sweet and juicy.
British growers now supply supermarkets with fresh strawberries from April to October, so if you finish picking strawberries in three weeks, consider extending your season by growing an early, mid and late variety.
Another good reason for trying new varieties is that they offer higher yields. R W Walpole is a family firm who have been growing strawberries in Norfolk since 1926, yet Paul Walpole is in no doubt that new varieties are higher yielding: “Old favourites such as 'Royal Sovereign’ or 'Cambridge Favourite’ produce 7oz and 12oz of fruit per plant respectively, but it is easy to find modern varieties that give 1½lb-2lb 3oz per plant,” he says.
When it comes to fruit quality, heavy rain, careless watering or wet soils can spoil the fruit and spread diseases such as grey mould (Botrytis), which makes fruits inedible. For high rainfall areas, Paul recommends varieties with waxy berries such as 'Fenella’ and 'Elegance’. 'Cupid’ is disease resistant, and also rain-tolerant, as its leaves protect the fruits.
Infection can often be traced back to planting too close or the flowers getting too wet. To prevent grey mould, always direct water at the surface of the soil, so the flowers are not wetted. When heavy rain is forecast, a temporary cover of perforated polythene will help.
Straw suppresses weeds and protects the ripening fruit from rot. However, it is vital to wait until there is very little risk of frost before laying straw.
Too early and you will only succeed in making the flowers more vulnerable to frost: the straw acts as a barrier between them and the insulating effect of the soil.
Tabletop growing is a commercial technique that uses growing bags raised off the ground and fitted with automatic watering. This gives growers more control over the crop, and uses less space. It also means they don’t need to sterilise the soil and there is better air circulation around the crop, meaning less disease. The watering and feeding is very precise, hence less waste of resources and less feed leaching into the water table. Picking the fruit is also easier, as is weed control.
For home gardeners, the ability to get more out of a small space, better quality fruit and ease of picking are all advantages that can be copied. Use eight to 10 plants per bag, and support them on a couple of upturned packing crates. Cut a plastic water bottle in half and insert it into the compost upside down. Give a regular dose of liquid tomato feed containing seaweed extract.
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