Archive for February, 2011

Is petrol expensive?

February 27, 2011
The price of Brent Crude Oil since 1987: Picture from Wikipedia

The price of Brent Crude Oil since 1987: Picture from Wikipedia

An interesting article in the Financial Times today [No, I haven’t started reading the FT: it had been left in a cafe] reporting that the national speed limit in Spain was to be reduced from 120 km.p.h. to 110 km.p.h in order to save money. I remembered that the UK and USA (amongst others) had lowered speed limits in the 1970′s as a response to a sudden rise in oil prices. The motivation then, as now, was to save the country money. The Spanish Deputy Prime Minister said

…the change would cut consumption of petrol by about 15 per cent and of diesel by 11 per cent, in a country where every $10 rise in oil prices costs an extra €6bn ($8bn) a year.

Now these are projections, and maybe not all these savings will come to pass. But this is a case where prices have increased enough to change behaviour. This is how we should judge whether petrol prices are ‘high’ in the UK. If we nationally want people to use petrol wisely then the price needs to be high enough to force people to consider changing their habits:

  • working from home,
  • increased videoconferencing,
  • changing job to be near home,
  • moving home to be near a job,
  • car sharing,
  • and avoiding certain journeys,
  • widespread adoption of fuel saving strategies.

Some of these things are happening now, but petrol prices probably need to rise still further in order to force the create sufficient ‘force’ to induce changes in infrastructure of our economy. In the meantime, it will be individuals and small business who feel the pain and poverty involved in this change.

Interestingly, the second part of the Spanish plan would additionally reduce the price of public transport, providing a rational counterpart to increasing the cost of private transport. I wonder if there is any chance of such a policy in the UK?

Another Mobile Phone Study.

February 26, 2011
Brain Images

Brain Images from the study along with their captions from the paper. The patterns show glucose metabolic rate as a colour vary. The pattern changes between the left image (phone ON) and the right image (phone OFF). In particular notice that there are changes in metabolism in ALL regions of the brain. Click on the figure to enlarge it.

The BBC report that  ‘using a mobile phone affects the Brain‘. Just before this story appeared I was sent the paper on which the story was based. “Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Mechanism” by Nora D Volkow et al published in the Journal of the American Medical Association (JAMA February 23, 2011-Vol 305, No8 pages 808-813). The paper is not freely available but you can read the abstract here.  This is a nicely constructed study which looked for the effects of mobile phone use on brain metabolism and reports that brain activity (as measured by uptake of glucose) increases during exposure to mobile phone radiation. With delightful understatement, the last line of the conclusions section of their abstract says: ”

The result is of unknown clinical significance

However I think this work is flawed, and I think the cause of the flaw shows exactly how hard it is to detect this kind of effect. All the PET imaging aspects seem impeccable to me – I am not expert in this field, and the protocol used – a single blind trial – in which the subjects did not know when (or if) the mobile phone held near their head was activated, seems reasonable. However the estimation of the RF dose seems to me overly simplistic. Let me explain.

  • The authors assumed the phone was a dipole radiator – yielding a particularly simple pattern of emitted radiation. The wavelength of the mobile phone radiation at 800 MHz is around 30 cm, and for a distance around the phone of roughly one wavelength, the emission pattern is complex: the so called ‘near field’ pattern. Why is it complex? Because the antennae in the phone are squeezed into odd shapes to make them fit inside the tiny handsets consumers demand. Every handset is different, and I have seen results from a wide variety of phones and the results do not look like dipole radiation patterns. So there is absolutely no reason to assume that emission pattern was like a dipole, however the researchers did not measure the actual emission pattern. This is a critical failure because (a) with the right equipment it’s only a couple of hours work and (b) their assertion that glucose metabolism levels are related to electrical field levels in the brain depends solely on their estimate of emission pattern of the phone. [See Author Reponse below]
  • Secondly, they simply switched the phones on and transmitted a voice message on tape to the phones. The phones were muted so the subject did not know whether the phones were on or not. The problem here is that the subjects did not speak. Most mobile phones employ a protocol called Discontinuous Transmission (DTX) which switches off the transmission function of the phones when the phone is not required to transmit (this saves on battery life). The authors don’t discuss this, and perhaps they were not aware of this, but if you don’t speak and the room is modestly quiet, the phone will barely transmit any RF signal. So there is actually no evidence of the dose of RF radiation produced.[See Author Reponse below]

The reason these issues are a problem is that, as the figure at the head of the paper shows, the metabolic activity across the brain changed quite a bit between data taken with the phone on and with the phone off. The average glucose metabolism is unchanged across the whole brain, but the researchers have picked one area of the brain and said that changes in this area of the brain are significant. The problem is that, as I have mentioned, I am not convinced that there is anything special about that area of the brain in terms of exposure to RF radiation. I am sure the authors would reply that “over the 47 subjects studied, if the area wasn’t significant then why would there be any effect when averaging all subjects?” And I would reply, “I don’t know, but’s it’s your job show that there is a relationship between dose and signal, not mine.” And then…

Michael: What’s your problem? Are you ‘on the side of’ mobile phone companies? What’s wrong with work that indicates mobile phones affect the brain? Well, I am not on anyone’s side. And I have previously stated that eventually someone somewhere would be able to detect the effects of phones on brains, and highlighted research that might have seen such things. And if these researchers had come up with a null result, then I would still have criticised their work on exactly the same grounds! But these researchers are making an extraordinary claim – that phones affect the activity of the brain – rather mildly, but nonetheless – a real effect. To justify such an extraordinary claim, I think the researchers should have checked out these issues that I have raised. Indeed perhaps they did but had to miss them out because the paper was too long?

The authors respond .

I wrote to the lead author and asked for her comments on this article. Her colleague Dardo Tomasi replied very promptly.

I said: “However the estimation of the RF dose seems to me overly simplistic”. Dardo Tomasi said  “We agree.  The reasons for selecting this overly simplistic model are:”

We observed an increase in glucose metabolism when the cell phones were activated compared when the cell phones were not activated.  This suggests an effect of cell phone in glucose metabolism.

  • The effects were significant only in brain regions that were the crossest to the antenna and within a very narrow range of distances to the antenna (15%); no region showed significant decreases.  This also suggests an effect of cell phone on glucose metabolism.
  • There is no way to measure the cell phone’s RF field in the living human brain.  Thus we were forced to use numerical simulations for the RF field.
  • A realistic model is very complex.  It depends on the assumptions about the form of the field and requires knowledge on cell phone electronics (i.e. type of antenna and RF circuitry).  The electric field will also be attenuated by the tissue itself. Thus it should take into account the distribution of different tissues in the human brain, which varies from subject to subject and is difficult to calculate or even measure accurately. Furthermore, a realistic model should be based on a near field approximation of the radiation field. For all potential models the E-field decreases with distance to the antenna.
  • Our data clearly shows a linear decay of glucose metabolism with distance to the antenna which strongly supports the overall conclusion that the RF fields are causing changes in metabolism in a pattern consistent with expectations, regardless of the exact functional form.  This also suggests an effect of cell phone on glucose metabolism.
  • For a dipole in the near field approximation the radiation field decreases as 1/r with distance to the antenna. Our over simplistic model assumed 1/r^3. We could not test differences between 1/r and 1/r^3 due to the narrow range of distances involved in the metabolic increases. In fact the radiation model fit the data as well as the simplistic model (R = 0.9 for both cases).  Thus, we were not in a position that we could detect model differences and used the simplest model.

I said “Most mobile phones employ a protocol called Discontinuous Transmission (DTX) which switches off the transmission function of the phones when the phone is not required to transmit (this saves on battery life)”

  • We monitored the RF transmission levels with an external antenna and with the summary report from the telephone company.  For one of the subjects RF transmission was interrupted before the end of the study and the subject was removed from the study. RF transmission was not discontinued for the remaining 47 subjects during the 50 minutes of the study

And so…

I could respond to the authors comments – but I think its pretty clear that they have done their best to tie down as many aspects of this experiment as they could. It is important to bear in mind that PET – positron emission tomography – is an extremely sensitive technique which can literally ‘see people thinking’. So if any technique could detect an effect of mobile phone radiation it is quite plausible that it would require such a sensitive technique to detect it. At this point I am  content to accept this as evidence that ‘something is happening’ in the region of the brain nearest the mobile phone caused by the microwave radiation from the phone. If this study is confirmed by further studies  then I am sure that eventually we will find out exactly what is happening to our brains when we make a mobile phone call. And then may be will figure out if that effect could be harmful in any way.


The effect of Alcohol. And Meat. And…

February 25, 2011


Hot on the heels of an article telling us that excess alcohol consumption is killing people, the BBC now report that insufficient alcohol consumption is also killing people. Specifically the article says:

… the overall risk of death was lower for those consuming small quantities of alcohol, 2.5g to 14.9g, compared with non-drinkers.

This corresponds roughly to a glass of wine a day. So the message is that people who live longest drink alcohol modestly.  Next the BBC tell me that eating too much red meat will also kill me prematurely, but are keen to stress that a little red meat is good for me.

Friends forgive me. But at my age (51) I have grown tired of reading this kind of nonsense portrayed as ‘news’. Doctors, who pronounce  this kind of stuff with earnest tones, do of course belong a profession well known for the avoidance of alcoholic excess. But the way it is reported makes me think the BBC is ignorant of the writings of Confucius who 2500 years ago developed the idea of ‘the middle way‘ and suggested that:

The guiding principle of the middle way is that one should never act in excess.

Well, I’ll drink to that.

Geothermal Energy: More Unanswered Questions

February 24, 2011
Mike Smith, Executive director of Southampton Geothermal Heating Company, in the engine room at the CHP plant

Mike Smith, Executive director of Southampton Geothermal Heating Company, in the engine room at the CHP plant

Having written yesterday about the unanswered questions regarding the Newcastle geothermal borehole, I was contacted by the eminent librarian and friend Bernard Naylor who said (paraphrasing):

Don’t be so skeptical – geothermal energy is alive and well and living in Southampton!

Suitably rebuked, I read about the Southampton scheme and the features that have made it successful. However I find myself suspecting – there goes my suspicious mind again – that the geothermal aspects of the Southampton project are actually irrelevant to its success.

The Southampton scheme is a Combined Heat and Power (CHP) Station. It is a small station generating around 2.5 MW of electricity from mainly gas and a little oil. It’s not as efficient to make a small power station as a large one – say 1000 MW, and the Southampton scheme appears to turn about 35% of the raw chemical energy of the gas and oil into electricity, compared with perhaps 45% or higher for large gas stations. However the Southampton system can play two trump cards. Firstly, it is in the middle of the City, not miles from town, so less energy is wasted (as heat in the wires) transporting the electricity. Nationally around 10% of electrical energy is lost this way. Secondly, the waste heat from electricity generation process is not wasted, but used to heat water to 80 °C which is circulated through insulated pipes to nearby hotels, shopping centres and flats. Overall, the CHP plant utilises something like 75% of the energy in the fuel. The scheme combines entrepreneurial spirit, local political infrastructure planning; and European Union and National funding. This combination appears to have nucleated a project which is an economic success, a source of local pride, and demonstrates a less carbon-intensive way to live in cities.

Where does the geothermal energy come in? Well scheme nucleated  around an old test borehole, but it is unclear exactly how much thermal power is extracted from the borehole. I have read claims that

If we guess these figures are approximately correct, this would imply an annual energy production of (say) 18% of 30,000 MWh which is 5400 MWh, equivalent a continuous heat output of around 600 kW. At an output temperature of 80 °C, this requires around 2 litres per second of water, or 172 cubic metres per day. If this really is the resource available, then I declare myself to be officially amazed. But I doubt that it is. It may been initially available from test boreholes but my guess – and it is a guess based on the British Geological Survey Estimate of the available heat flow outside of Cornwall – is that actual output is just a few percent of this value. If you have any information on this I would love to hear about it!

My ex-colleague Stephan, commented on yesterday’s story to say that in Germany/Munich they have local geothermal generation (possibly this scheme?) which initially produced 118 litres per second of water at 130 °C (presumably under pressure). This is a phenomenal energy output: around 50 MW! I am sure the output temperature would quickly decline as water was drawn from such a resource. As Stephan comments, this not harvesting a sustainable resource, but simply cooling a large block of rock. This report also comments that the output of the Southampton scheme will decline but I have not read whether the decline is over years, decades or centuries. My guess is years.

Is it worth it? Well this brings me back to the basic point I made yesterday.

  • However much we might like geothermal energy to be implemented, it will not happen until it makes economic sense.

If one has a hole in the rock out of which a large thermal resource flows, one would be bonkers not to use it. In Southampton, the geothermal element of the project may helped initiate the CHP project, but it is now (IMHO) largely irrelevant. The key feature of the Southampton scheme is that it is using precious carbon resources around twice as effectively as the rest of the UK. This is the real success that should be trumpeted and praised and, most importantly, copied.

Geothermal Energy: Unanswered Questions

February 23, 2011
Professor Paul Younger (left) and Professor David Manning from Newcastle University prepare and test thermal water from their 400-metre borehole at Eastgate in Weardale. Photograph: Mike Urwin

Professor Paul Younger (left) and Professor David Manning from Newcastle University prepare and test thermal water from their 400-metre borehole at Eastgate in Weardale. Photograph: Mike Urwin

The BBC reports today on the commencement of a Geothermal Energy project in Newcastle. The academic in charge, the esteemed Paul Younger, says that ‘geothermal energy operates 24/7’ and the reporter happily parrots the factoid that in July the borehole will produce ‘water with a temperature of 80 ºC’. And as I listened and read, I searched for the fact that would change this from PR for Newcastle University into reporting. The reporter should have asked ‘How much?’. As in:

  • How much water will be produced at  80 ºC each day?

My suspicion – and please forgive me for being suspicious – is ‘not much’. I can boil water with a magnifying glass on a sunny day, but not much! In order to make sense, such a scheme needs to capture not just hot water, but lots of it!

What is your point Michael?: Now I think this is a great research project and I am glad that we collectively are funding it. But except in a rather small number of locations, the amount of heat rising up through the Earth per unit area of Earth’s surface is tiny: somewhere close to 0.1 watts per square metre. In the UK the average is less than this, excluding Cornwall the measured values are in the range 0.058 ± 0.016 watts per square metre. So to produce an output of (say) 100 kW(thermal power) requires the collection of the heat from an area around 1 kilometre x 1 kilometre. This either requires a complex arrangement of boreholes, or the exploitation of water seepage through natural cracks in the rock. All in all it amounts to a complex engineering structure and it does not run itself. Water must be pumped, cleaned, and returned or disposed off.  If the thermal output were 100 kW at 80 ºC this would involve the production of 400 millilitres of water per second, or around 34 cubic metres of water per day.

Cost: My (optimistic) guess is that such a piece of infrastructure might cost on the order of £1million to construct. It could replace the heating of 33 standard 3kW immersion heaters (Capital Cost ≈ £500) or around 5 standard domestic gas boilers (Capital Cost ≈ £15000). I can’t guess the running the cost of the geothermal project, but if we imagine that the £1million must be repaid at 0% interest over say 10 years the cost is ≈£100,000 per year.  If we imagine we need to maintain the facility or manage it in some way or pay for the pumps then the cost would be more than this. For immersion heaters, the running cost is £175,000 per year assuming one pays 20 p per kWh. And for gas boilers the running cost is £40,000 per year assuming one pays 4 p per kWh. So the capital costs of a geothermal project are enormous, and the running costs are similar or higher than conventional options. If a council said it was going to take £1million of its residents’ money to invest in such a project, but that there would be no financial benefit to the residents, then I think we all know what would happen to the council.

So what?: Now the carbon costs of the geothermal project are difficult to estimate – drilling through rock is amongst the most energy intensive activities conceivable! – but I have gone through this analysis to make one simple point.

  • However much we might like geothermal energy to be implemented, it will not happen until it makes economic sense.

And it won’t make economic sense until energy prices rise way beyond current levels.


The Richter Scale

February 23, 2011


Map of recent New Zealand Earthquakes

Map of recent New Zealand Earthquakes

Dramatic news from New Zealand about the recent Earthquake. I have never experienced an Earthquake and it sounds like one of the most baffling and terrifying experiences a human being could ever live through: How could the Earth itself move?! Now every ‘Earthquake story’ is accompanied by a statement of the strength of the Earthquake on the Richter Scale and for once the BBC has done us proud with a relatively comprehensible article on the subject. Thank you BBC.

The recent Earthquake registered 6.3 on the Richter scale and has killed 75 people so far, whereas the magnitude 7.1 Earthquake last September 2010 killed no one. The Haiti earthquake in January 2010 was a magnitude 7.0 shake and killed tens of thousands. Is this Richter scale really a measurement that reflects the deadliness of an Earthquake? No. The Richter scale measures the amount of energy released in an event. But the scale is very strange:

  • Every 2 points along the scale corresponds to a change in energy released by a factor 1000. So a magnitude 8.0 earthquake is 1000 times more energetic than a magnitude 6.0 earthquake and 1,000,000 times more energetic than a magnitude 4.0 earthquake.
  • To find the ratio of the amounts of energy released in two different Earthquakes one needs to do a sum. First one subtracts one Richter number from the other, and then raises 10 to the power of the difference. So for the two recent New Zealand earthquakes one subtracts 6.3 from 7.5 to give 1.2. One then raises 10 to the power of 1.2 using a  calculator to yield 10^1.2 = 15.84 or approximately 16.

So the recent earthquake was 16 times less powerful than the September earthquake. One can calculate the amount of energy associated with these events. Wikipedia has a tabulation but for reference, a magnitude 7.0 earthquake corresponds to the release of a phenomenal amount of energy:

  • 2 Peta joules of energy i.e.
  • 2000 million million joules of energy i.e.
  • 2 000 000 000 000 000 joules of energy, which is equivalent to an explosion caused by
  • 474 thousand tons of TNT or around 22 bombs similar to that which was dropped on Nagasaki.

And just like a bomb, the amount on damage inflicted depends on several factors

  • How far away one is from the bomb site – the epicentre of the Earthquake:
    • The further away one is, the less the effect
    • The deeper the Earthquake the less the effect at the surface.
  • How well protected one is:
    • In a bomb shelter one can gain a certain amount of protection from a bomb.
    • Similarly, buildings designed to resist the shaking of Earthquakes can afford protection.

The magnitude 6.3 quake was equivalent to the explosion of ‘only’ 4 atomic bombs, 10 km from Christchurch at a depth of 5 km. To my mind that sounds like a truly terrifying prospect. I take my hat off to the people who developed building regulations to withstand that. And I express my sympathy to all the people in the locale for their loss.

Protons for Breakfast 14!

February 22, 2011
The fourteenth presentation of Protons for Breakfast approaches

The fourteenth presentation of Protons for Breakfast approaches

I have been thinking a lot lately about Protons for Breakfast. It’s on my mind because – well – its always on my mind! But also we are approaching the fourteenth presentation of its modern era, and we seem set to have record numbers – more than 110 people signed up as of last week. Many people have asked me if I get nervous about the course, or if I find it difficult to enthuse about topics about which I have spoken many times before. For the record, the answers to these questions are “Yes” and “No” respectively. And for the same reasons!

I do worry very much about each presentation because I feel so strongly that the simple insights that the course provides can really enhance people’s lives. And it pains to me think that something I do (or forget to do) might get in the way of communicating optimally. One of the nice ‘chores’ before each course involves collating all the comments and questions that people have written on their application forms – it really does help me to get my mind to where people are ‘coming from’. And its great fun to try answer questions along the lines of “What are space and time?” in a paragraph or two.

Work is very challenging at the moment, and in principle it would all be a bit easier without having to put on this ‘show’. But in fact putting on Protons for Breakfast is a real pleasure: meeting people, working with my NPL colleagues, and spreading the word about the value that can be added to people’s lives by the realisation that they eat Protons for Breakfast! .

Marshall Stoneham

February 22, 2011
Marshall Stoneham: 1940-2011

Marshall Stoneham: 1940-2011

I first met Marshall Stoneham when Birkbeck College closed its Physics Department in 1997 and I sought refuge at University College London, where he was a senior Professor. You can read about his achievements and awards in many places (e.g. at UCL, or IoP ), and they were well deserved because he was brilliant and hard-working. But on the web you may not read about the simple fact – indeed the most overwhelmingly important fact about him: that he was a thoroughly kind and decent man. I feel proud to have been able to call him a colleague, and so sad to learn of his passing.

Design or Engineering?

February 22, 2011
A 'designer' shoe

A 'designer' shoe

Yesterday my wife, my children and I visited the Design Museum and had an interesting and informative couple of hours looking at the exhibits, particularly the entries nominated for the BRIT Insurance Design Awards. Photography was banned but you can get a flavour of the exhibits from some BBC coverage here. And wandering around I was struck by the thought that I didn’t really know what it meant to view ‘design’ as a distinct process.

The exhibition included:

  • Furniture: including some chairs which could be sat on comfortably, and others which were interesting, or fascinating, but not very … functional.
  • Apps for the iPad. I thought this was computer programming but apparently it’s design.
  • Installation art – such as Mimosa or a ‘Wall’ on which one could throw virtual paint from a cyber bucket.
  • Lights: some strange and some practical and attractive, and some of which generated light when trodden on.
  • A Fiat 500, nominated for its innovative two cylinder engine.
  • The system of ‘Boris Bikes‘ used for hire around London.
  • A bicycle with no gears and a fold-up electric bike which looked like it simultaneously optimised lethality and impracticality.
  • A coffin and a system for creating tubes out of laminated wood.
  • A shoe which had been printed using 3-D printing. In honesty it was barely recognisable as a shoe and the consensus of the people gathered around was that if worn it would be on the fashionable side of uncomfortable.

By grouping all these objects together the Design Museum seems to claim the creation of each of these objects involved a distinct process called ‘Design’. And they did all look as though they had been designed: however many looked as though they had been designed badly! And I felt that somewhere in this process, engineers were being short-changed.

For example, I am sure that every curve and shaped component in the engine of the Fiat 500 is result of an intensive design process: but by automotive engineers. And the software used to calculate the load-bearing properties of the uncomfortable ‘shoes’  was designed by software engineers. And the machine which ‘printed’ the shoes (think Thing-o-matic) was designed by mechanical and electronic engineers. And the plastic used to manufacture the shoes was itself the subject of design by chemical engineers.

It seemed that the process of ‘design’ had been commandeered by iPad-wielding, fashion-conscious ‘designers’ and the achievements of the engineers which underpin all these ‘designs’ was being seriously overshadowed.

The effect of alcohol

February 21, 2011


”]A bottle of wine and thou... [Ed- surely that's 'a glass' not 'a bottle'?]My few regular readers (hello :-)) may have noticed that I have recently been concerned about the additional risk I am taking on by being officially ‘overweight‘ (BMI = 27). Shifting my BMI involves a good deal of effort and attention to details of my life that I feel to busy to pay attention to at the moment and, in short, I would like to know ‘ Is it worth lowering my BMI to 25?’.

On a  similar theme, I was taken by a recent BBC story about the effects of alcohol. The gist of the story is that a group of Doctors say that:

… if nothing is done, deaths from all alcohol-related causes – including cancers and road accidents – could claim the lives of 250,000 people in England and Wales over the coming two decades

Now that is a lot of people, but on the other hand 20 years is a long time. So the additional deaths amount to 12,500 per year. Again, a large number, even compared to the roughly 500,000 deaths per year in the UK (link to barely comprehensible Statistics Office Data see table D). But of course these people would have died anyway so they are not additional deaths but in fact earlier deaths. And often quite horrific deaths which are expensive to treat. So people drinking too much shorten their own lives, bring suffering on themselves, and bring avoidable costs to us all. And it’s these facts that ought to be the focus of these reports.

However from my personal perspective, I am frustrated that from the data given in the article it is impossible to work out anything meaningful for an individual. Like an answer to the questions:

  • If I have one more glass wine every day, how much am I shortening my life?
  • If I have one less glass wine every day, how much longer might I expect to live?

Now I don’t pretend that these are easy questions to answer, but these are the questions to which I personally would like an answer. And since we all pay the BBC to report and analyse ‘news’, it’s the kind of analysis I would like to read, instead of reading the simple repetition of statements from a press release.


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