Feedback: your letters

Topics under discussion this issue: IT and control camps must talk; dead end for Coalene; a brief history of German traffic management projects; the truth about Luigi Galvani's frog's legs and more.

IT and control camps must talk

I read with interest in the 25 October 2008 issue of E&T the warning that industrial process control systems are under threat from viruses, trojans and worms ('Process security systems "have more holes than Swiss cheese"').

For a number of years now, I have worked in the process control systems and anti-virus field and can echo many of the points raised. In the last ten or so years, process control systems have tended to use standard IT equipment, usually supplied by third-party vendors to plant or department engineers. As management has become more interested in plant data, these same systems have steadily been integrated into site IP networks, and this has happened without any consultation or knowledge of the IT department.

Consequently, there can be hundreds of machines on a company network that do not follow the IT policy of anti-virus and Windows updates, and more importantly are not supported by anyone. From this position, it is difficult to introduce said software, but not impossible.

The method I have employed on numerous sites is: take an inventory of what is out there and not covered by the IT department; take a backup of each machine; install anti-virus software and monitor its operation and fine-tune if necessary; install Windows update software and monitor likewise.

This is a very easy approach, but one with many obstacles. The biggest is usually that of change. Most engineers will employ a policy of "If it ain't broke, don't fix it", whereas IT departments will use the latest equipment, software, upgrades and patches. Engineers will have been told by the system suppliers that anti-virus and Windows updates will either stop their control applications working or they cannot guarantee their application operation should any other software be installed. However, I have found that most suppliers will work with you, usually by fine-tuning the scanning and update settings of the software.

Confidence is the next biggest hurdle. Having persuaded the engineer that the company IT policy is to be rolled out to the process control systems, it has to be guaranteed that it will not adversely affect the operation of the plant. This is as much a people skills exercise in trust, as this confidence will build as you work with the engineer during backups and initial installations and vendor consultations. The problems I have found here are when anti-virus suppliers or Microsoft roll out an update with a problem that can actually stop systems working. Engineers will rightly comment that the very methods for avoiding plant stoppages due to virus infection are now responsible for causing said stoppages. To repair the damage to the process control systems is usually much easier than repairing the damage to the confidence of the engineer.

Engineers and IT specialists should work together to devise a common specification that is capable of conforming to company policy and system suppliers' applications.

Martin Shaw CEng MIET, Rotherham

Dead end for Coalene

Further to recent letters concerning Coalene oil, I was involved a few years ago on a project relating to the feasibility of utilising Coalene oil derived from the low-temperature carbonisation of shredded tyres at the plant to which John Walton refers at Bolsover.

Fundamentally the 'run of retort' gases were condensed, cleaned and refined with a view to being fired in either a gas turbine or reciprocating engine as the characteristic of the Coalene oil was similar to that of diesel oil. By-products to have been recovered and recycled would have been carbon and metal from the tyre reinforcement wires.

Due to the presence of trace elements of various heavy metals however, no commercially available turbine or engine could be found that would tolerate the contaminants on an operationally reliable basis. The fuel was suitable for boiler combustion via a rotary cup burner though, and in this mode it was successfully utilised.

Alas the whole plant economic model would have been financially sustainable only when used in conjunction with reject heat recovery on the exhaust exit and selling all the power generated. The project also carried the financial burden of a 40 per cent duty as the resulting Coalene oil was not considered to be a waste product when used to generate power.

The scheme was abandoned as being non-viable and the former Bolsover site is now in the process of being cleared for redevelopment.

Stuart Kay IEng FIET, Chesterfield

Not so fast

The 11 October 2008 issue of E&T reports that the German town of Ingolstadt is hosting an experimental traffic management project in which traffic lights are networked and can communicate with cars to streamline the flow of vehicles, for example by indicating what speed must be maintained to pass through the next lights at green. As every car must be modified to take advantage of this, why not have the required speed indicated on the gantry, available to all vehicles, then you know that maintaining the indicated speed will allow you to pass through the next light at green ?

New idea? Not really, the Heerstrasse in Berlin had this system installed at least 30 years ago and it is very effective. I would always find someone who would flash past me in their car as I slowly proceeded at the indicated speed only to smile at them as I passed while they prepared to pull away at the next traffic lights.

At times ideas can become over-engineered just because we have the technology. The in-car application will take years to become effective but if the system of speed indication could be installed with gantry displays it would immediately be available to all vehicles with the corresponding reduction in fuel consumption and emissions.Once this system was in place then we could have the reception into the cars. As the in-car system is a function of position, time and distance I could see this, eventually, as being an add-on to satnav equipment.

Leslie Lord MIET, by email

Galvani - the truth

I was disappointed that the Eccentric Engineer column in the 11 October 2008 issue repeated the myth that Luigi Galvani discovered that a dead frog's legs would twitch if a current passed through them.

This was already a known phenomenon around 1790, and almost a party trick for anyone with an induction machine, but not it seems to Galvani. What he (or more likely his assistant) did discover was that if he hung a dead frog by its exposed lumbar nerves using copper hooks suspended from an iron bar and then touched the leg muscles with the iron bar, they convulsed without the need for the induction machine. Unknown to Galvani, he had created a simple electric circuit and electric cell with two different metals - copper and iron.

He then decided that nerves contained a life force and the circuit was connecting this to the muscles. He ignored the facts before him: that it only worked if the metals were dissimilar; that the junction of the two different metals had to be wet (ideally with an acid); and that completing the circuit with a single metal did nothing.

Volta repeated the experiments and came to the correct conclusion that it was the wet junction between the two different metals that was creating an electrical effect and that zinc and copper had a stronger effect.

Bob Bell MIET, by email

Engineers rule

'Ruled by engineers' in Issue 17 was a fascinating piece, but left out of the list of religions that are repressed in China Christianity. It is true that there is some official recognition for Christianity through the government-controlled Three-Self Patriotic Movement (TSPM) church organisation. At the same time, unaffiliated Christian groups such as the house church or underground church movement have been fiercely suppressed, with buildings razed, and leaders hounded and imprisoned.

Since you mention that China's ruling party is led by engineers, let's consider these actions from the engineering point of view. You're faced with something bigger and beyond you that you want to get a handle on; what do you do? Step one: adopt a model (which in practice is a 'good enough' approximation to reality). Step two: minimise (repress) the aspects of reality that don't fit your model. We do this all the time - minimise non-linear effects, etc. to keep our calculations simple. Step three: implement a system using that model.

In this case, take over and use the TPSM churches as the (almost) exclusive legitimate model. Good engineering practice!

Another salient point in the article is the remark about how this scientific materialism seems to have fallen short. Don't laugh - it happens all over the place, when professional scientists and engineers cross the fine line to become amateur philosophers. (I'm even doing this now!). Then we all face the danger of being swept along by the hubris, of believing our own PR, and we start to confuse all our sacred engineering models (convenient approximations and reductions of reality) with reality itself.

Terry Koh MIET, by email

Brute force engineering

Paul Dickenson's request (11 October 2008) for advice on how to listen to his TV without disturbing others and without a long cable to his headphones is interesting. My solution, a few decades ago, was a great success.

I bought a cheap 2W amplifier chip, on a Veroboard, and fitted it into a small 'click-clack' plastic box, along with headphone jack, switch and 9V battery. Its input device was a coil of thin enamelled wire on a 3in Ferrite rod - I didn't count the turns, but it must have been several hundred!

Fortunately, a suitable length of scrap multicore telephone cable just happened to fall off the back of a lorry near our house. I fitted it under the floor of the living room (we had a huge basement) and laboriously soldered the ends together, on another Veroboard, to form a single coil.

The coil was connected by a length of twin flex, through a hole in the floor, to the TV's speaker, via a c/o switch of course. To my surprise, and the delight of our young son, it worked fine from the word go! An excellent example of design by "brute force and bloody ignorance".

Stuart Bridgman MIET, Brooklyn, New Zealand

Turbine downtime

Whenever I see a terrestrial wind farm, either in the UK or abroad, up to about 25 per cent of the wind turbines are standing idle, even in good wind conditions. I recently saw an offshore wind farm on TV and, again, it was noticeable that a significant number of the machines were not working. If wind turbines are intended to save fossil fuel I should expect them to be, nearly all, operating flat out, whenever they can.

Is there something about the reliability or the down time of wind turbines that is not generally being revealed ? What is going on here ? Would the wind turbine people like to comment ?

Dr R Barnes CEng FIET, King's Lynn


In our news story 'Digital gallery brings art to rail travellers' (E&T 2008, #8), the hardware for the project was specified and procured by Sysco, not Cisco as we stated. We are happy to clarify this.

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