Last week you had a story from ABB about a new surgical technique for children suffering from osteosarcoma, a form of bone cancer. Many of you asked for more technical detail.

Surgeons replace a section of diseased bone with an adjustable insert that allows the bone to be lengthened, keeping pace with the healthy limb. In the past, this involved frequent surgery to access the implant and operate a screw jack to lengthen it.

Engineers at the University College London, based at the Royal National Orthopaedic Hospital at Stanmore, have produced an implant that can be activated by electromagnetic induction.

The ?bionic bone? has a miniaturised high-ratio gearbox driven by a rare-earth permanent magnet synchronous rotor no larger than a one pence piece and 4mm thick. The gearbox is only 21.5mm diameter and 18.5mm long and drives a power screw which lengthens the ?bone?, developing the 200 Newton force required for every 1mm of extension. The complete rotor / gearbox assembly is embedded within the implant and activated by applying a rotating magnetic field .

The patient?s leg is inserted into a cast-resin three-phase stator, powered by a Danfoss VLT 2800 variable frequency inverter. The variable torque control of the drive enables the rotor to produce sufficient torque to drive the gearbox at as low as 40 to 60 volts at 50Hz, and provides accurate flux control to protect the tiny gearbox from torque overload. To ensure smooth rotation at this low stator voltage, the drive output waveform is filtered before being applied to the stator.

A single-phase to 3-phase VSD is essential so that the stator can be powered from a domestic 240v single-phase supply.

With gearing of 13,061 : 1 and the rotor spinning at 3,000 revs, the gearbox develops 4Nm torque and extension of 0.25mm per minute is achieved and timed rather than measured. Despite the asymmetrical air-gap, and the tissue of the leg, between the stator and the Niobium Iron Boron (NdFeB) rotor, there is excellent magnetic stator / rotor coupling, regardless of the fit of the patient?s limb within the stator and so there is no need for immobilisation or discomfort for the patient during a typical 15 minute treatment.

The cost of the implant is ?12,000 against ?4,000 for initial surgery but savings in subsequent surgery and aftercare offsets the cost.

Cooper Bussman's fuses had a hand in helping the Rolla Solar Car Team from the University of Missouri win the 2003 American Solar Challenge Race.

The challenge was to build a solar powered car and race it approximately 2,300 miles from almost one side of the USA to the other. The course took them from Chicago in the east, to Claremont, a suburb of Los Angeles, in California. The Missouri team took just 51 hours, 47 minutes and 39 seconds, beating the previous race record by more than four hours.

Busmann donated a number of its FWX series 80A semiconductor fuses to provide circuit protection for the solar vehicle.

Solar flares - heading our way Navigation systems, satellite phones and sensitive electronic are feeling the effects of turbulent solar weather. Solar flares, the largest recorded for many years have produced solar radition that has reached Earth's atmosphere. Electrical grids, satellites, pagers and mobile phones that rely on orbiting spacecraft can sometimes be affected. In 2000, a solar blast created steering problems for several orbiting spacecraft. One hit the main electrical utility in Quebec plunging millions into darkness for hours and costing billions of dollars to fix. A solar flare is an explosion on the Sun that happens when energy stored in twisted magnetic fields is suddenly released. Flares produce a burst of radiation across the electromagnetic spectrum, from radio waves to x-rays and gamma-rays. The results of a solar flare swept past Earth yesterday but the impact was weak Scientists tracking heightened solar activity in recent days reported some commercial airlines have had to make adjustments to their high-frequency communications, or in some cases switch to alternate satellite systems. More are approaching Earth and could trigger bright auroras when they arrive today or tomorrow.

From 1995 to 1996, manual handling injuries cost UK employers almost ?335 million. CBI Director General Digby Jones, said: ?People are more aware of their rights and more willing to take legal action.? A commercial vehicle that saves labour, reduces injury risk and can even improve productivity is designed with a hydraulic system that raises and lowers the cargo floor. It enables its entire load bed to drop to ground level for loading and unloading. Called the Razorback, the vehicle can be fitted with a variety of front wheel drive cab options. For electrical contractors the vehicle has a number of benefits for loading and unloading panels, heavy equipment and cable reels. As the entire load bed can be fully lowered to the ground, the contractor can directly wheel loads on and off from ground level. It has a payload of 1000kg and operated at the push of a button. At 3.5t, the Razorback can be driven by anyone with an ordinary car licence. It has a two-year, unlimited mileage warranty.

For further information contact:

Motor stators, supplied free of charge by ABB, are helping children with bone cancer to walk again.

The children being treated at the Royal Orthopaedic Hospital, Stanmore, have lost part of their leg bones to cancer. Because a large amount of bone has been lost, a prosthesis is implanted in the patients leg to support the remaining bone. As the child grows, the implant must be extended to keep pace with the skeletal growth. This typically involves three or four operations a year over a five-year period.

Eliminating the need for painful surgery, a research team at the University College London (UCL) has pioneered a non-invasive procedure that involves placing a small magnetic rotor in the patient?s leg. This is linked to the prosthetic implant by a gearbox and is turned by an external stator. To increase the length of the prosthesis, the patient?s leg is placed inside the stator core.

When energized, the stator turns the rotor at 3,000 rpm, which drives the gearbox and extends the prosthesis by one millimetre every four minutes. A typical treatment will extend the prosthesis by four millimetres over the course of four minutes.

Quick and painless, the procedure can be performed in a clinic

A combined heat and power plant will be built in Sweden to provide electricity and district heat for the city of Gothenburg.

The plant, to be provided by Demag Delaval Industrial Turbomachinery, will comprise three 43MW gas turbines and a 141MW steam turbine. It will have an overall efficiency of 92.5% and will feed 260MW of electricity into the Swedish grid. The work should be completed by the end of 2006.

The deal forms one of four orders that will make the company a total of ?230m.

The second order is for two 29MW gas turbines, to be supplied to a combined heat and power plant that will provide power for the Russian town of Sochi. The contractor is JSC City Energo, Moscow, and the end customer is RAO UESR (Unified Energy System of Russia). The plant is scheduled for completion by autumn 2004.

The EPC contractor, Technip of Italy, has placed an order on behalf of end customer Motor Oil Hellas. Demag Delaval Industrial Turbomachinery will provide a 17MW gas turbine to a refinery in Corinth, Greece.

The firm will also supply a 100MW industrial steam turbine, with instrumentation, control system and spare parts, to Jindal Power Private Limited in the Belleray District in Karnataka State, India.

American Superconductor has supplied the Tennessee Valley Authority with the first SuperVAR dynamic synchronous condenser, which stabilises grid voltages, boosts service reliability and could help to maximise transmission capacity. The product is said to reduce the threat of power outages by ensuring that supply voltage is properly regulated. The condenser acts as a shock absorber for the grid. It absorbs or generates reactive power, depending on the voltage level of the transmission system. The product also protects against voltage transients caused by lightning storms and other unforeseeable occurrences. The need for utilities to ensure balanced reactive power on their grids has become an urgent priority since the recent blackouts highlighted their vulnerability. ?In today?s digital economy, keeping voltage levels constant and stable is vital,? says the executive vice president of Transmission Power Supply Group, Terry Boston. ?That?s what TVA?s customers expect, and we believe that?s what this new technology will help us deliver.? The SuperVAR synchronous condenser has been installed at TVA?s electrical substation, which serves a steel mill operated by the Hoeganaes Corporation in Gallatin, Tennessee. The company will buy five more condensers if the original purchase proves successful.

Powergen has announced that it will raise its electricity and gas prices from 5 January as a result of pressures facing suppliers.

The price increase is largely due to the sharp increase in wholesale costs, which have risen by over 25% for electricity and 18% for gas in the last twelve months. Other difficulties include the rising cost of gas transportation, system balancing and costs incurred by the Renewables Obligation.

The increase will be an average of 6.9% for electricity and 4.9% for gas. Prices will remain the same for small business contract customers and customers on capped price products until their contracts expire.

In an attempt to help its more vulnerable customers, Powergen says it will not increase the prices for prepayment meter customers until April, with Age Concern and Staywarm customers paying the same prices until the situation is reviewed in spring.

The managing director of Powergen Retail, Nick Horler, says: ?Powergen is not alone in facing these increasing costs but it is the only leading energy supplier not to have raised its consumer electricity prices in seven years. Even as our competitors? electricity prices have gone up over the course of this year, we have held off. With this change, these prices are still 12% cheaper in real terms than they were in 1996 while, for gas, at least eight out of 10 households would be better off with us than British Gas.?

The U.K. renewable energy industry may not reach the government-set target of providing 10% of the country's energy by 2010, according to a report released today by Standard & Poor's Ratings Services. Wind power, which is expected to be the main means of reaching this target, may suffer from under investment. "The Renewables Obligation scheme, introduced in April 2002, may not provide sufficient incentives for investments in renewables," said Standard & Poor's. Infrastructure Finance credit analyst, Jan Willem Plantagie, comments: "The U.K. scheme appears less supportive than in other EU countries. This and other factors mean that the U.K. lags considerably behind countries such as Denmark, Spain, and Germany, despite having a greater abundance of windy weather." The report, entitled "U.K. Blows Hot and Cold Over Wind Power", outlines the challenges faced by the wind power sector in the U.K and examines the current U.K. regulatory framework for wind power projects. It accompanies a more general report, also published today, entitled "Are European Wind Power Projects on their way to Investment Grade?" covering the major credit concerns of wind power projects in Europe. Both reports are available to subscribers of RatingsDirect, Standard & Poor's Web-based credit analysis system, at

The use of gas turbines for power generation is well established. The risks associated with it arise from the use of fuel under pressure, often in an enclosure, the high speed rotating equipment, noise, and electrical hazards. There have been a number of major incidents, and a larger number of lesser incidents in recent years. HSE was concerned over these risks and the dangers to personnel.

HSE published the first edition of PM 84 in 2000 as a means of providing guidance to manufacturers, suppliers and operators, and to its Inspectors, on the principles that should be applied to reduce these risks so far as possible.

The first edition of PM 84 was well received and has been widely applied. Following comments from the industry, requests for additional information and references, technical developments, and incident experience, HSE has revised and expanded the guidance.

The risk assessment section has been revised to take account of recent legislation, in particular the requirements of DSEAR, the Dangerous Substances and Explosive Atmospheres Regulations 2002 which implement the Atex "Workplace" Directive.

It is anticipated that the revised document will represent a clear and comprehensive set of guidelines, and will help to improve and maintain a high safety standard in this industry pending the publication of ISO 21789, a new Gas Turbine Applications Safety Standard, which is currently being drafted.

Newey & Eyre has launched a new range of personal protective equipment (PPE) for electrical contractors and installers.

The free catalogue also includes a range from US-based PPE firm, Vallen, and Newey's believe that the selection of core products cover most hazardous scenarios.

For a free catalogue, contact Newey & Eyre on freephone 0800 783 6909.