Title: Projects and developments

Pages: 30 - 31


Author: Editorial

The dancer calls the tune
Professional dancing as an art form has always used music as the basis for the artist to express in terms of movement of the body. An engineering graduate of Stanford University has now invented an 'instrument' which uses the dancer's movements to create the music.
William Potts put together an electronic synthesiser similar to those used in electric organs with two miniature keyboards held in the dancer's hands. Two joint sensors attached to selected joints pick up 'myoelectric' signals produced by the muscles which control the volume and can be made to produce sliding notes much like a trombone.
The keyboards are held in the palms of the hand; notes are selected with the right hand, octaves with the left. Six full octaves are used and it is possible to play multiple notes and multiple octaves.
Potts says he wasn't very excited about his invention until he met professional dancer, Barbara Petersmeyer who demonstrated it in a 'fascinating' manner.
The present device connects sensors, keyboards, synthesiser, amplifiers and speakers to a cable attached to the dancer's belt. Potts believes the cable could be replaced by a transmitter, leaving the dancer with more freedom to move.
Potts began work on the project in 1972 as part of his master's degree in mechanical engineering product design. Since he had no background in electronics he enlisted the help of Brent Miller. Following use by many other dancers and musicians, the instrument is now being redesigned in the light of their experience.
(Caption) Sensors located near two joints control the volume: notes and octaves are selected by hand

Floating on air
It is a long time since the invention of the wheel revolutionised prehistoric industry. Its effect was to reduce the power required to move a load from that of, say, 200 men to only 20. But both modern man and the Stonehenge architect would have been equally amazed to see just two men manoeuvre one of that temple's great stones into position with total precision. The secret is the 'air bearing', now perfected to industrial scale, which has already found its way into 1000 US factories and has just arrived on this side of the Atlantic.
Known as Rolair, the device is simply an air-supported bogey consisting of a steel platform with a membrane of elastomeric urethane material fitted underneath. The membrane is inflated by air (or water) which is allowed to leak through to create a 0.003in lubricating layer between the bearing and the floor. A compressed air supply of 690kN/m2 (100lb/in2) and a reasonably good floor surface are the only requirements, according to the makers, and the floor and operating pressures are normally about 70-100kN/m2 (10-l5lb/in2). The effect, however, is that a 1000kg load requires a force of only about 1 to 5 kg to move it. Loads can be manoeuvred in any direction and with extreme accuracy. Capital costs are claimed to be up to 90 per cent cheaper than conventional handling equipment while maintenance is virtually nil because there are no moving parts.
Major users of the system include US aircraft and motor manufacturers while, in its first UK order, the company is providing four bearing units to move 150 tonne generators; contracts for 600 tonne transformer units are under negotiation. The largest single application to date is in a sports stadium in Hawaii where four spectator stands, together weighing 7000t, are being mounted on Rolair transporters so that they can be moved regularly between football and baseball viewing. Information from Rolair Systems (UK) Ltd. 56 Brompton Square, London, SW3 SAG.

Graphics open up software markets
Computer graphics form a powerful method of getting information into and out of computers. They permit managers, engineers, scientists or accountants to 'converse' with computers in a way which is familiar; they also handle a prodigious amount on information in many forms: graph, drawing, perspective, cross-section.
Until now there has been no equally universal method of programming computers for graphics. There are standard languages for numerical programming FORTRAN, ALGOL, PL1 for example - but graphics are handled in a fragmented and non-standard way. Computer graphics needed a completely general programming system to run on any computer and capable of operating all the many graphics devices now available.
The Computer Aided Design Centre, in conjunction with ICL is now marketing a graphical software package, GINO-F, for use on all ICL computers. CAD Centre has also signed an agreement with Logica to market GINO with certain IBM machines.
It can be used in two or three dimensions on graphs, technical drawings, maps together with text and annotations. Design parameters can be changed quickly by using a simple keyboard and the results of the change displayed immediately on the screen.
One of the many ways of demonstrating the flexibility and power of computer-aided displays and computers in general is by means of a game - chess is probably the highest game form a computer has yet handled. GINO-F is no exception and three dimensional noughts-and-crosses between computer and player comes over very clearly. Simulated golf is another favourite with some.
The price of display terminals - about 2000 - is effectively bound to come down in the next decade, and with the cost of software programmes being relatively cheap, it is perhaps surprising diet no-one has seriously considered marketing a library of games software for the consumer market. It certainly might help allay public suspicion that all a computer will do is persistency send bills for the wrong amount.

Battery breakthrough for electric vehicles
The recent announcement of a sodium-sulphur battery a tenth of the size of conventional lead acid batteries leaves the development of efficient electric vehicles wide open. The battery, developed by the Electricity Council, is already driving a Selnec bus in Manchester (DESIGN 308/20) and a new joint company formed by the Electricity Council and the Chloride Group expects to produce commercial sodium-sulphur batteries within four years. This company also intends to develop specifications for the machinery needed for bulk manufacture and will then license interested manufacturers.
The crux of the new battery is its electrolyte. It has to stand up to two chemically active materials in molten condition and yet allow sodium ions to pass through it when it discharges giving up electricity and its charge. The answer proved to be a special variety of ceramic called beta-alumina.
When the early popular scientific stories came out some thirty years ago they explained plastics in terms of specially-designed 'tailor-made' molecules; essentially similar achievements, though with vastly different chemicals, are at the base of the development.
Originating in an obscure German thesis, the discovery of the unique properties of this special form of alumina were first tested for scientific feasibility as a battery material in the USA. The Electricity Council Research Centre at Capenhurst then picked it up and carried it a stage further producing a material that would stand several thousand charge/discharge cycles, still able to transmit sodium ions. Yet the material is free of any tendency to short-circuit the battery.
Electrical connections are made through aluminium leads to the liquid sodium negative electrode inside the electrolyte tube, fed from above by further sodium in a stainless steel reservoir. The positive electrode, liquid sulphur, sits in a ring-shaped space between the electrolyte and the outer case. As the battery is used and discharges, sodium diffuses through the solid electrolyte and more sodium flows down from the reservoir above. Since sulphur is an insulator, the outer space of sulphur also contains porous carbon to provide electrical conduction. During discharge the sulphur is converted to sodium sulphide, then regenerated during charge.

In brief
A THERMOSTATICALLY CONTROLLED BATH for handicapped patients has been developed by Meynell Valves of Wolverhampton. The bath has grab rails and an ambilift device for manoeuvring the patient into the bath. To release the nurse for other duties, the patient can use a shower with a trigger grip attached to a flexible tube.

THE 'OMNI-OVEN' developed by Ratheon for the US army combines microwave energy, infra-red, and a steam pressure cooker in one oven. It is part of a computer-controlled project to get the best roast results at government installations by determining the best combinations of cooking methods, intensities and times.



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