I am a mechanical engineer and that fact greatly informed what I saw. Technically, the fists and forearms of a boxer can be described as padded hammers. The upper arms of a boxer serve as, what people would usually describe as, hammer handles. Padded or soft-faced hammers are used in order to avoid localized damage owing to high-intensity stress. In the case of boxing gloves, the padding would reduce surface bruising by distributing the applied force over a relatively large area. They would also reduce tearing that might result in blood loss. To be more specific: an unpadded hammer with protrusions (such as the knuckles of a hand) could cause deep indentations wherein the skin and underlying tissue could be damaged by compression or stretched to tearing point; also, any blows that are oblique relative to the target surface could stretch the skin and tissue sideways, causing tearing. In boxing, padding of the hammers reduces the occurrence of gory injuries to the target, and to the hammers themselves. A mechanical engineer or a physicist would know that surface effects are only incidental to the purpose of a hammer.
]]> A hammer is a device to apply impulse. This is a highly technical term, which I will try to explain as straight-forwardly as possible. A hammer has a head that is relatively massive, or heavy; two examples of hammer heads are the glove, fist and forearm in boxing, or the steel head of a blacksmith’s hammer. The idea is that over a distance, known as a swing, the speed of the mass is increased progressively until, just before impacting the intended target, a high speed has been reached. The higher the final speed is, the higher is the efficacy of the hammer. Furthermore, for every doubling of the speed, the ‘efficacy’ of the hammer is quadrupled. The energy that the hammer-head has just before impact depends on the mass multiplied by the square of the speed (i.e. the speed multiplied by itself, as in 2 × 2 = 4 or 3 × 3 = 9. As the hammer makes contact with its target, much of the energy of the hammer is transferred to the target in a very short space of time indeed. As contact is made, a very large force is exerted for a very short period of time: this is what physicists and engineers mean by impulse. The very large force causes the hammer to decelerate very quickly indeed and, if the target is capable of moving, causes the target to accelerate.Many people are familiar with the collision between a moving snooker, pool or billiard ball and another stationary one of the same mass. The moving ball comes to a complete and sudden stop, while the stationary ball is suddenly accelerated to have nearly the same speed as the stationary ball had. Looking at my own forearm, hand and head, I would guess that the mass of my head is somewhat greater than the mass of my hand and forearm, but, in boxing, the mass of a boxing glove would also need to be added to that of the hand and forearm. It seems to me that, roughly speaking, the human head may be somewhat heavier than the hammer that is likely to strike it in a boxing match. Roughly speaking, the collision is similar to the one just mentioned between a moving and a stationary snooker ball, but the head may not reach as high a speed as the fist had. The head, of course, is restrained by the neck and its muscles. These quickly bring the head back to zero speed, although the sensation for the recipient of the blow is, I’m sure, a very unpleasant one. To summarize the story so far, when the head receives a high velocity hit in a boxing match, it is subjected to a very high force distributed over quite a large area that causes the head to suddenly accelerate to a velocity somewhat lower than the striking glove had, whereupon the neck muscles are called upon to bring the head back to a stationary state as quickly as possible.
My knowledge of anatomy is rather limited and I am not claiming any medical expertise whatsoever. A large part of the skull is filled with the brain, which is soft tissue having an average density that is slightly higher than that of water. The brain is surrounded by and almost floating in a liquid, having a density similar to that of water, which fills all spaces between it and the hard cranium. The small difference in density between the brain and the fluid that surrounds it tells me that the brain is very delicately suspended within the skull. Almost all of its weight is counter-balanced by buoyancy forces. Nature, as usual, is ingenious. The brain is a computing engine and every part of it needs to be fed continuously with oxygen carried in blood that flows through it.
As I understand it, there are various partitions or partial partitions that separate regions of the brain within the skull. The brain is not rigid, but rather is very capable of being deformed. To a casual observer like me the brain appears to be somewhat like a half-walnut in a half-shell. However, the brain does not have the rigidity of the walnut. The laws of mechanics indicate that when a human head is struck in a boxing match it undergoes very high acceleration and deceleration. However, because the content of the cranium is not rigid or firmly held in place, different parts will undergo different rates of acceleration and there is likely to be considerable relative movement within the brain tissue itself or between the tissue, the surrounding fluid and the cranium. Partitions, protrusions, outcrops of bone and orifices, all of which I believe exist, are likely to impact against the soft tissue of the brain and subject it to stresses. If there are parts of the brain that are more- or less-dense than other parts, local stresses would be increased considerably. Perhaps some mechanical extrusion, or local severe compression or tearing of brain tissue can occur. Here I am definitely speculating and guessing.
Coming back to what I believe I saw in the video: I saw the taller boxer’s head being struck repeatedly in very quick succession by high velocity punches and I saw it recoiling repeatedly. I think of a plastic container that is sometimes used for making-up salad dressing. The container has a fixed circular disk inside that has some radial spokes (like those of a wagon wheel). Some oil and vinegar, which have different densities. are put inside, perhaps with a little French mustard and pepper. The container is shaken vigorously by hand for about thirty seconds and the French dressing is then ready. The disk with the spokes helps to break up the fluid and enhances the mixing. The video of the boxing match showed the tall boxer’s head being shaken violently by rapid, repeated impacts from multiple directions. There is no question of the brain being broken-up and mixed like the ingredients of a salad dressing—the human being would be damaged long before that would occur and the referee would have declared the winner. To me, as a mechanical engineer, it is no mystery whatsoever that boxers can suffer horrific brain damage, or death. And, by the way, in my opinion head protection would not make the scenario acceptable: an analogy might be to make up French salad dressing by wrapping the container already mentioned in a very thick tea-cosy—it might reduce the intensity of the shaking somewhat. In boxing, head protection further reduces the likelihood of surface damage, but is inadequate to protect the brain. In my humble opinion, a sport played in such a way that the head of a human being can be abused, as I have seen, is a cruel sport.
]]>There was quite a large audience in the Michael O’Donnell lecture theatre, which included a representative of the Minister for Transport and members of various organizations. I do not know what proportion of the audience consisted of ordinary members of the public, but there were certainly individuals there who had very strong feelings about this particular piece of Ireland’s heritage. I found Frank Prendergast’s openness, professionalism and his respectful acceptance of diverse views inspirational.
The human condition and nature are both fascinating. Thankfully, society is made up of artists, poets, archaeologists, engineers, politicians, farmers, environmentalists etc. It is good that people do not all hold the same views and it is good that different people care more- or less-deeply about different things. Somehow society as a whole moves on, with ups and down, even though individuals may be pursuing different dreams.
For my own part, I believe motorways are necessary for today’s society and, given that resources are always scarce, it needs to be possible to construct them cost-effectively. Frank Prendergast displayed a relief map of Ireland in his presentation, on which he had spatially mapped known archaeological formations such as man-made mounds or configurations of rocks. The map made it clear that these exist almost everywhere. Frank also demonstrated, by an example, that in the course of civilization on the island of Ireland, since some time after the last ice age, constructions of one era have been dismantled in order to use the materials for some other purpose, perhaps another construction. The words I have been using are probably not the correct archaeological language: Frank used the correct, and much more precise, terms in his lecture.
It was clear from some of the questions and observations from members of the audience that not all of them were comfortable with the concept of preserving the traces of the Lismullin post enclosure by record only. My own opinion would have been much more accepting of what had been done. While he was careful not to take sides, Frank pointed out that, in his view, detailed data, with scholarly and professional assessment and analysis based upon it, could in itself be a national treasure. That struck a chord with me. As I referred to earlier, I felt happy that there was still a part of the remnants of the post enclosure that was undisturbed. With future techniques not yet imagined those remnants, or telltales, may yield a lot more information. Nature herself is self-documenting: she retains sufficient traces of every era that are, or will become, amenable to analysis. But, even nature re-uses and re-distributes materials; for instance, this would have occurred by massive compression of surface layers under the weight of ice and subsequent scouring as glaciers moved during the ice age that Frank mentioned.
I learned at the session that the carbon-14 dating technique had been used to establish the date at which the trees that were used for the posts of the Lismullin enclosure were felled. (For me, this technique is built upon one of the marvels of nature: she creates radioactive carbon isotopes in the upper atmosphere that become part of things that are currently alive. The half life of the isotopes is around 5730 years and so, amazingly, even tiny fragments of charcoal contain a type of count-down timer that was activated at the moment the material was no longer living.) I learned that other analysis of charcoal residue has allowed the species of the posts to be determined and has suggested that another species may have been interwoven around the posts, creating a fence or wall. Detailed analysis of the metrics of the post enclosure has shed a lot of light on the technical capabilities and the societal activities of those who constructed and used the post enclosure. Another lesson I learned from the lecture was that the importance of the Lismullin enclosure is not singular. The society that existed at the era of the enclosure can best be understood by putting the site into a much broader historical and archaeological context.
Those who regard Lismullin and the landscape around the Hill of Tara as sacred ground have a valid viewpoint. I respect that view and, in a sense, I encompass it in my own view that the island of Ireland is sacred ground for us, the Irish who live on it now. I believe that at Lismullin there has been a reasonable compromise. I am scarcely a poet, but I imagine nobody could know better than a great poet the importance of record.
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Certificate: F-E-accolade-Oct_2010.pdfBeing a mechanical engineer and an academic, I imagine that I am far from being a typical Kindle user. I did not buy it primarily because I wished to buy books through Amazon, although I have been an Amazon customer for book purchases for quite some time. I was very interested to experience just how good the electronic ink technology had become. I was also very interested in being able to load my own documents, such as technical lecture notes, or a student's draft PhD thesis I was reviewing. I was curious about whether the 6-inch screen would be adequate for reading PDF files of journal articles. It is adequate for these things, although I believe the larger format version would be better for reading journal articles. The standard Kindle, which has the major advantage of portability and compactness, should be a lot more adequate with some further development, mainly to incorporate finer steps of zoom for PDFs and better panning. I scanned the Kindle, displaying my own lecture notes, at 600 dpi. The image below was re-sized to 50 dpi, but you can see a sample at 600 dpi by clicking on it.
The available zoom values are: fit-to-screen, 150%, 200%, 300% and actual size. In many cases I found these insufficient for reading PDF documents. Generally too, I found it necessary to use landscape format for reading PDF documents, which is fine, but necessarily requires several views per portrait-format page. Where a diagram crossed between views it was not possible to view it at maximum magnification in one view. Vertical panning capability would address that issue.
I commonly experience sore eyes because much of my work as a lecturer and researcher is done at a computer screen. I believe electronic ink devices can alleviate this problem and I am looking forward to further progress, such as computer screens based on electronic ink.
The Kindle came in a very sturdy box, which I am keeping to transport it. I ordered the Kindle without a protective cover, to save that cost. With just a little more ingenuity on the part of Amazon, that excellent package could be modified to be a bundled, free, transporting case for the Kindle that would be thinner than it currently is. The surplus thickness is principally to accommodate the USB cable, which could be safely packaged in currently-empty space that surrounds the Kindle. The transport case would not necessarily serve the same purpose as the nice covers that can be purchased. I like to use the Kindle as it is, without a cover, but I need to carry it in my back-pack on my daily commute. Since purchasing the Kindle I received an e-mail from Amazon offering a vast array of covers for sale. Clearly, Amazon makes a huge profit on these. In my local low-cost shop, Penneys, I can purchase covers of netbook size for €3 to €5, whereas similar covers of Kindle size, which is smaller, would cost €25 from Amazon. I hope Penneys will soon have Kindle-sized covers in stock—there should be strong demand for them.
The Oxford English Dictionary is my favourite and so I am really delighted that the Oxford Dictionary of English comes as standard with the Kindle. For me this is super added-value. However, I have been finding it a little irritating that the dictionary entry appears on screen for almost every word before which the on-screen cursor is placed (thankfully, prepositions, conjunctions etc. are excluded). Maybe I’ll get used to it, but surely there is a power consumption overhead too. This could be déjà vue on a massive scale, [n. [mass noun] a feeling of having already…. It only happens, of course, when I activate the on-screen cursor and not when I am reading normally. I only found this to be an issue when reading PDF documents.
As I had done my homework thoroughly, I knew what to expect when I got the Kindle. Overall it has lived-up fully to what I knew I could expect. However, the Kindle did start off by un-impressing me somewhat. I took out the Kindle and, following the instructions, connected it to my computer with the USB cable provided. A message then appeared on the Kindle telling me that if I wished to read it while continuing to charge the battery through the USB cable I could do so by ejecting the drive letter but leaving the cable connected. That did not work. I ended-up having to wait until the Kindle was fully charged, because I did not wish to disconnect it during its first charging cycle. I have since found that the procedure mentioned does work provided wireless connectivity is turned on.
In Ireland thousands of secondary school children carry rucksacks full of large heavy books to school every day. Over the years the books have become bigger and thicker. It is no exaggeration to say that on a typical school day my son’s very large school bag feels like it is full of concrete blocks. I believe damage is done to the backs of many children on this account. Many parents feel compelled to ferry their children’s school bags to school, even though the children themselves would be capable of walking there if they were not over-encumbered. Alternative solutions have been available such as wheelbarrows, which have not proved popular. Neither have wheeled airline-type trolleys, because they are often considered insufficiently manly. Electronic schoolbooks will totally solve this problem. I hope they will also solve the problem of the exceedingly high cost of schoolbooks in Ireland.
Although I have generally bought books in the past through amazon.co.uk, in the case of the Kindle I had to purchase through Amazon.com and it was shipped from the US, having been manufactured in China. Publishers around the world operate highly anti-competitive practices of restricting sales to geographical or political regions. Artefacts of previous times are still in place. With the advent of instant electronic publishing, these practices, in their present form, are no longer appropriate and need to be reviewed on a worldwide basis. We live on one world that has no natural barriers to the flow of information. It is the case that personal income levels vary greatly from one part of the world to another and, therefore, prices will have to vary in accordance with some mechanism, for the present. However, the challenge for world leaders and for organizations such as the United Nations is to embrace the new technological possibilities and harness them to bring about more equity, access and fair competition.
Although I purchased the Kindle with wireless access only, because it is sufficient for my needs, Amazon has made a major breakthrough in making the downloading of data available to Kindle users without any additional payment for access to the 3G network in Ireland. So far, in Ireland, regulation has been insufficient to prevent the network utilities for charging excessively for data download. It is only quite recently that one mobile phone company has shown openly on its web pages (though it is not easy to find) that it commonly charges €20.48 per MB of data downloaded from the Internet. Prices for data access will need to become a lot more reasonable in Ireland and I believe Amazon’s move is a step forward.
Besides reading technical PDF documents and the on-board user manual, I have downloaded and am currently still reading one book, for free, in Kindle format, from Project Gutenberg. This is highly satisfactory. The ability to choose a font size that suits is a great convenience. I have also found the Kindle excellent for reading a particular blog that I am interested in, although accessing it is somewhat complicated and the Kindle does not allow the same facility of moving around as a normal web browser would. As presently configured, the Kindle is primarily for reading that is sequential. The ability to resume where one has left off is well worth having, as is the possibility of highlighting text, defining bookmarks, making notes and saving cuttings.
I look forward to being able to borrow library books for reading on my Kindle. Until now I have often used Amazon to find and purchase second-hand books. I hope this will also become possible for pre-owned Kindle format books. As a technical person, however, I appreciate the authentication and legislative challenges that exist. Technically, Amazon has been a trail-blazer and it has made excellent progress. It would be truly tragic if such progress were to be stymied because of a lack of worldwide political action or failure to manage the one world. Worldwide action to protect copyright material in an appropriate manner and to facilitate the distribution of open-access material is essential. Perhaps it may not be feasible to sell-on electronic-format books for ‘second reading’—positive creative thinking is needed here, such as a reasonable charge for transfer of ownership.
The topics I have mentioned in this review are just a small selection of aspects of the Kindle and of the new era that the Kindle has opened-up. There are many challenges ahead to make all of this work in a way that makes sense, incentivizes innovation and efficiency, rewards writers, publishers etc. appropriately, and yet yields enormous benefits for mankind on the one globe, Earth.
]]>I have found that ticket inspectors on trains and staff at ticket counters are generally reluctant to accept complaints (in order to pass them on and have them acted upon). Usually when I raise an issue they indicate that I need to raise the matter with management or with head office or with customer service or by writing-in. I have done all of these things too over the years, with very mixed levels of response. For the most part I have been left feeling that the matter I raised was uncertain to be passed-on or dealt-with. As with the banks and financial institutions, a strong and competent regulatory authority at national level is required to enforce the standards. Furthermore, a strong and competent European regulatory authority is required to enforce the standards of the Irish regulatory authority.
Let me take a superficially humorous example. There have been occasions when the PA system at Heuston Station has announced that the train now standing at a certain platform, (say platform 6) is a certain train (say for Portlaoise), but the train was not actually standing at that platform. On one occasion, following such a PA announcement, and when the train was still not at the named platform perhaps five minutes later, I walked a long distance back to the customer service desk in Heuston station. I pointed out that, even as I was speaking to the staff member, the train was not where the PA system had said the train was. I pointed out that this raised the question of where the train actually was. I wondered were the signals and control systems correctly reporting where the train was. I have a strong suspicion that the staff member at the desk thought I was a crackpot. He told me that the PA system was only broadcasting a recorded message. As an engineer, that type of situation causes me concern. Why should an automated PA system be able to broadcast an incorrect message, falsely indicating the location of a train?
There is a lot of civil engineering involved in running a railway, but there are a lot of other types of engineering involved as well. One situation that has really damaged Irish Rail’s credibility in engineering terms, in my eyes, has been the introduction of automated barriers at Heuston Station. This saga, which has been going on for perhaps two years now, is a sorry one. Automated barriers exist at commuter stations around the world and, from my experiences in cities like London and Paris, they seem to operate very well. At Heuston station my experience of the automated barriers has been a very negative one. They seem to have been faulty since they were installed. They cause considerable frustration and delays for passengers and they do not fulfil their intended purpose of ensuring that everyone who passes through has a valid ticket. Although this is not a matter that causes injuries, it is a significant engineering failure. A private individual who purchases a car that does not work would return it and get a full refund. In the case of this automated barrier system, which I am sure was installed at great cost, this does not seem to have been possible. ‘Engineering’ extends to effective purchasing, commissioning and follow-up where equipment fails to satisfy its intended purpose.
The responses I have read so far in relation to the Malahide Viaduct Collapse seem to place the responsibility for preventing any recurrence of a railway bridge collapse on Irish Rail. That is where the responsibility should lie, but it must be enforced. All aspects of standards within Irish Rail and within the transport sector generally must be effectively regulated.
]]>Bad though this disaster continues to be, it could have been worse. This incident has made it clear to me that a much more serious incident of this general nature is capable of being produced. I feel that the the conclusion of Claire O’Connell’s article underplays the magnitude or seriousness of the lessons that need to be learned. It is not just that in this case everybody who should have been keeping their eye on the ball didn’t do so and will need to pull-up-their-socks, as it were.
Full public technical explanations are required as to what happened and precisely how the technical failures occurred. It is only in this way that provisions and procedures can be devised that are verifiably adequate to address the risks. How and why did the blow-out and fire occur on the drilling rig? Why did the blow out preventer on the sea floor fail to operate? Why was it not subsequently possible to close off the leak by means of the blow-out-preventer that remained in-situ throughout the entire incident? Could a scenario of the type that occurred have been foreseen by those who granted the licenses for the operations?
From following the technical updates on the web it has been clear to me that the engineers and scientists involved were struggling to comprehend exactly what they were dealing with. Even now it seems there is uncertainty about which areas of the entire well are subject to pressure coming from the reservoir. This is the nature of engineering and science: I recognise and accept that fact and I appreciate that many engineers and scientists have been working non-stop on the case. The job is not yet finished and there may yet be significant challenges in ensuring that the well is permanently plugged. It is important to make the technical questions and the conclusions reached public, e.g. through publication of comprehensive technical papers and reports. Such information must not be kept commercially confidential. It must be shared.
The technical issue that concerns me the most is that of dealing with the enormous pressures that exist in oil reservoirs deep beneath the sea and deep within the Earth’s crust. My own rough calculations suggest that the pressure at the bottom of the MC252 well must be about 936 bar, which is more than 900 times atmospheric pressure. In oil drilling and recovery operations this huge pressure is counterbalanced by the weight of drilling mud or crude oil within the well bore. However, in certain circumstances, which are still apparently not well understood, pressurized gas can fill part of the well bore and cause a, perhaps rapid, increase in pressure at the top of the well (of perhaps hundreds of bar).
Another technical issue of major concern, and the one with the potential for causing the greatest environmental damage, is the risk of opening up a large-bore communication between the oil reservoir and the surface. The entire leakage flow in the 2010 Gulf of Mexico spill had to pass through the bottom of the well bore, which had a casing of only seven inches diameter. From some of the quotations in Claire O’Connell’s article it might be understood and accepted that the configuration-controlled leakage from the oil well was perhaps less serious than the leakage caused by the splitting of a super-tanker. However, the occurrence of a large bore communication between an oil reservoir and the surface, or even between the reservoir and higher strata within the Earth’s crust could be very serious. It seems to me that these risks may need to be re-assessed in the light of the Gulf spill.
My professional opinion is that for the foreseeable medium term (say 100 years) it will be necessary to continue to drill for oil, even though the technical challenges are great. I believe this is a necessary part of the overall mix in attempting to achieve sustainability for mankind.
The 2010 Gulf of Mexico oil leak has been very serious and historians will make the assessments of its relative seriousness. The Earth can take the hit in the fullness of time: I feel confident about that, but I also realise that this resilience is of no consolation to those tragically or directly affected. I also believe it is right that commercial companies should be held fully accountable for their actions.
]]>I do not understand why the pressure in a well with integrity should rise continuously. I would like to be reassured about this, but I suspect it remains a matter of debate among the engineers who are involved directly. It is easy to say ‘this is what we would expect’ in retrospect and perhaps find a justification for that expectation such as: while the oil spill was occurring the pressure within the reservoir was relieved and, now that the flow has been halted, the pressure is moving back to an equilibrium value. Perhaps the well is being replenished from a deeper level. These things would be difficult to verify, although they could be modelled. An oil reservoir containing a significant proportion of dissolved methane under enormous pressure is a complex system. An update of 2 August, which gives a revised estimate of total leakage (4.9 million barrels, of which 0.8 million were contained so that 4.1 million barrels flowed into the ocean) indicates that detailed modelling and analysis have been taking place.
Another possible explanation for a continually increasing well-head pressure is that the density of the column of oil within the well from the sea bed down to the reservoir is decreasing. Gaseous or lighter components may be rising to the top within the well bore, while heavier components may be sinking back into the reservoir. I have the impression that the original blow-out may have been linked to a lightening of the column of crude oil within the well bore. A very significant slug of gas within the well bore could have caused a huge increase in pressure at the well-head.
To put this in perspective I have estimated that the pressure in the oil reservoir is about 13,600 psi or 936 bar. The presence of the column of crude oil within the well itself counteracts this pressure, reducing it to the measured 6,928 psi (478 bar) at the well head. The weight of the oil within the well bore provides a counterbalancing pressure of about 6,672 psi (460 bar). A significant gas slug within the well bore could increase the well-head pressure by a significant fraction of this amount.
I am a little uneasy that a collapse of the relief well bore occurred over 40 feet close to the interception site. Those in the business may be comfortable enough with this, but It makes me feel wary.
When disasters occur, the general public must often wait for a very long time for the explanations of what went wrong. I wonder whether BP can give a clear and precise explanation of exactly what things went wrong in the original accident. Can BP give an assurance that the blow out preventer on the relief well can be relied upon should it be called into action?
It does appear that considerable care is being taken in preparation for plugging the well. For instance, it is planned to pump mud into the original well at a very slow rate for a static kill. This sounds sensible to me. My own rough calculations indicate that a ballast mud density of up to 1363 kg/m3 (11.4 pounds per US gallon) would be required. However, while waiting this long to finally plug the well has probably been wise and fully justified it seems to me that completing the job cannot be delayed too much as that would increase the risks of a blow-out.
I do not believe that the exploitation of deep undersea oil reserves should be abandoned because of this Gulf of Mexico oil spill disaster. However, there may well be a need for a moratorium until all the issues can be addressed appropriately. Clearly also, on the basis of what has happened, much tighter regulation is required. Thinking ahead also, it may not always be wise to allow a commercial enterprise that causes an environmental disaster manage the arresting of the incident and the solution of the causative technical issues, even under close supervision. I am appreciative of the fact that the US Government has done a lot to maximize openness and transparency, but I would urge even greater technical openness. For example, I would like to have all the data (e.g. composition, densities, continuous pressure readings, viscosities, known or estimated temperature profiles within the formation, drawings of the BOP etc. so that I can calculate the leakage rates and perhaps try to understand what has been going on in terms of applied thermodynamics and fluid mechanics).
I have carried out my rough calculations using Maxima, a free and open-source computer algebra system. A printout is available at this link: GOM_Oil_Leak_Calcs_r008.pdf and the original Maxima file is available at GOM_Oil_Leak_Calcs_r008.wxm. Others are free to make use of these documents in accordance with the Creative Commons licence http://creativecommons.org/licenses/by-sa/3.0/.
]]>The original explosion and fire on the Deepwater Horizon platform cost human lives. It would not be acceptable to continue such operations in the same manner until the mechanisms involved in this disaster are understood and appropriate measures can be taken to address them and assure the safety of personnel when there is a sudden major surge of methane gas.
]]> It seems to me that the environmental damage is huge. It will be a long time yet before the true extent of that damage can be quantified. I do not wish to over-dramatize this either. While it is no consolation to those who have lost loved ones, those directly affected in myriad ways and those who are deeply concerned, Mother Earth is capable of taking the hit, which is not to say that she will remain unchanged and undamaged. In the long history of the Earth I feel sure there must have been even greater natural releases of crude oil from beneath the sea. However, this does not excuse any failure to take all appropriate precautions and all appropriate remedial actions.A blow-out was to be anticipated sometime, as blow-outs have previously occurred many times and are well documented. Lessons have been learned from previous blow-outs and this present disaster is the first of its type. Presumably the blow-out preventer that was installed contained multiple levels of redundancy. Nonetheless, it could have been envisaged that the blow-out preventer might have failed. What were the intended steps to be taken in such an event? They may have included ‘top kill’, the placing of a heavy capture dome, the placement of a lower marine riser package (LMRP) cap and the drilling of interceptor wells. Henceforth, these will be inadequate contingency plans. Undoubtedly, oil companies and regulators will take this on board.
In what ways did the blow-out preventer (BOP) fail? Did the hydraulic actuators or mechanical drives fail to move the rams that would seal the bore of the BOP? Was there a freezing effect, owing to the expansion of dissolved gas, that locked everything solid? Methane hydrate (an ice of water and methane) seems to be implicated in the various phenomena associated with this disaster, whether within the oil and gas reservoir, within the well riser, within the BOP, in throttled flow or within jets of pressurized oil and gas that mix with seawater.
BP have published a graphic of the LMRP cap. I do not understand why it has been impossible to achieve a leak-tight seal. It seems the pipe emerging from the BOP was cut with a diamond wire saw, but the cut may have been finished with shears, which would have left a surface that was not ideal for sealing. Perhaps a tool could be made that would allow this surface to be ground down to the necessary flatness. Given that there is a flange at the top of the BOP it should be possible to apply enough clamping force to achieve a seal. As a mechanical engineer I find it extremely disappointing that, given the time that has elapsed, it has not been possible to achieve a leak-tight seal at the top of the BOP.
I’m not quite sure, but it seems it has been possible to insert coiled tubing into the well riser. I do not see why my own idea of inserting a long, heavy taper into the well riser could not be considered: it would require modifications to existing technology. The taper I envisage would be constructed from standard drill pipes of increasing diameters. Taper couplings to go between these could be manufactured quickly. It could be weighted with drilling mud, perhaps even with the addition of steel or lead balls. Such a system would allow a well to be plugged relatively quickly, stemming the leak until the well riser had been intercepted at a low level. Perhaps there is a fear of allowing unrestricted full-bore flow while preparations are made for the insertion of the taper. This may be a valid objection, but it could be checked-out. My impression is that this may be a self-choking flow, which may have been very close to full-bore choked flow just after the pipe was severed above the BOP by sawing. Is it possible to fully unrestrict the full bore of the BOP by moving the rams outwards? I don’t know.
I am not aware of the state-of-knowledge of high pressure two-phase flow, as it relates to this disaster, but it seems there is an urgent need for a detailed understanding of how the flow develops within the well riser. From my own experience of refrigeration it seems that there is some analogy between the well riser pipe and the capillary tube used in refrigerators. In refrigeration the flowing liquid changes phase, whereas in a pipe containing oil and dissolved gas the gas may come out of solution. The maximum mass flow rate is determined by the possible flow of liquid, but the emerging flow will tend to be choked two-phase flow. The analogy stops there.
The major additional factor in the case of the well riser is that the pressure seen at the floating platform can vary by roughly the full hydrostatic head of the entire column of oil. At one extreme the entire riser could be filled with pressurized gas, while at the other it could be filled with liquid. As total depths have increased this has become an increasing problem. Where the BOP cannot be fully closed, as is still the case in this disaster, it can be impossible to inject heavy fluid from the top. A taper could perhaps be inserted.
I just have a hunch that in the long run a (nearly) full-depth heavy taper within the production bore might provide a means of managing the extremely variable two-phase flow conditions of wells such as that in the Gulf of Mexico.
Engineers may also need to consider ways of providing a liquid and gas separator at a depth close to the reservoir. This could allow separate risers for liquid and gas to be used. Theoretically an ideal riser through deep water for liquid or gas would incorporate self-acting throttle restrictors that would would maintain a pre-determined excess pressure over the hydrostatic water pressure within the riser. Delivery at the floating platform would occur at modest pressures.
It strikes me too that hard questions need to be asked and answered about the ability to permanently seal abandoned deep water oil and gas wells. Extremely serious though this disaster is, even worse disasters need to be contemplated. There have been some suggestions that explosives (even nuclear explosives) be used to try to block the leaking riser. Wisely, I believe, this approach has not been judged appropriate. One could imagine uncontrolled flow through a damaged well riser eroding the riser and eventually providing a large bore communication between the reservoir and the seabed. What are the contingency plans if this were to happen?
In meeting the needs of the Earth’s growing population and humanity’s growing total appetite for energy there are no easy answers and there are global-scale risks with large scale harnessing of energy, no matter what the source. In my view there is a need to pursue all technical options in search of the best compound solution, but with due diligence and an appreciation that the one Earth is a shared resource of all of humanity.
]]>Unaware of the existence of a comparable device, such as the EPOS-enabled Digital Pen, I thought there must be many ways that the device I had in mind could be realized. To narrow the options, I decided to let the ball be light-permeable. The technical name of the device could be ‘an optical ball pen stylus’. The marketing people might come up with a trendier name like a Stilly: a silly stylus with memory. The descriptions below are my original ideas and are not identical to those implemented in the commercial device.
]]> The Basic ConceptThe concept relates to a handwriting or drawing implement with a ball tip (similar to those used in ballpoint pens and roller ball pens) that is light-permeable. The ball tip would be spherical and would form part of an optical lens system that would allow an image, mapped from the patch of contact of the pen stylus with a surface, to be captured on a miniature, or micro, optical image sensor within the pen stylus.
There would be multiple possible variations of the invention (and combinations of those variations) and there would be multiple applications of the different variations. Figure 1 illustrates the basic concept.
Figure 1 Basic concept
Variations of the Concept
In one variation, the optical image would be produced by ambient light that penetrates the ball. In another variation the tip would be surrounded by a light emitter or an array of light emitters, e.g. Figure 2. The light could come from a direct light-emitting device (e.g. light emitting diode, incandescent element, fluorescent element, plasma device, or laser) or could come from such a device indirectly (e.g. reflected or refracted light, light tube, fibre optic light transmission). The light could also come from the surface over which the pen stylus moves.
Figure 2 External light emitter
In yet another variation, light would be provided to the ball tip from within the optical pen stylus, according to the general principles of the scheme illustrated in Figure 3.
Figure 3 Internal light emitter
The ball tip could be of various sizes, depending on the area of application of the device. It is envisaged that a major application area would involve balls of the sizes currently used in ballpoint and roller ball pens. However, much smaller balls could be used, limited only by the wavelength of the light or electromagnetic radiation used. Much larger balls, virtually without limitation of size, could be used. Variations using hollow balls or cylinders (wheels or rollers) would also form part of the class of device described here. As a further variation, a fixed or non-rotating ball tip could be used.
The ball tip will generally require being very hard, although for some applications (e.g. use on a flexible screen or display) a softer, more flexible material might be appropriate. For a hard, light-permeable and tiny ball, synthetic diamond or cubic zirconia (which both happen to have very high refractive indices) could be used. Other light permeable synthetic or natural gems, ceramics, or fused or sintered materials could be used. For larger, less-hard balls a wide range of materials (e.g. glasses or plastics) could be used.
The compound lens indicated in Figure 1 could be made up of as few as one component—a light-permeable mono block, which would serve as a light transmitter, or light conductor. Its function is to convey an analysable representation of the contact area region to the image sensor. In the special case of a non-rotating tip, the ball tip and the compound lens could be one integral unit. The compound lens might also be considerably more complicated, involving materials or substances of different refractive indices and curved interfaces between components. The compound lens system could be of a fixed characteristic, or could incorporate possibilities of adjustment.
As is currently the case with optical mice (used as human interface devices for computers), the captured image would be analysed in real time to register all movements of the ball tip while it is in contact with a surface. Furthermore, the form of the contact patch would be recorded (as a movie: think of an aircraft following the meandering course of a river while recording the appearance of the river directly below), which would enable the as-drawn line to be memorized (including the line weight and texture). The resulting data would be passed on by wire (or optical fibre) or wirelessly to a computer or processor. The processor could be within the pen stylus or external to it and the data could be stored within the pen stylus or externally.
In one variation the optical pen stylus would contain ink, as in a ballpoint pen or roller ball pen. This ink would be sufficiently non-opaque that light could enter through the ball and an image of the patch of contact between the ball and a surface could be transmitted to the internal image sensor. The non-opaque ink could be of thick consistency, as in a ballpoint pen, or of a thinner consistency, as in a roller ball pen. With an internal light emitter system, as illustrated in Figure 3, there would be less of a need for the ink to be light-permeable. Various ink storage and supply systems could be used. Figure 4 illustrates a possible arrangement.
Figure 4 Ink duct around the compound lens and the internal image sensor
The general class of device might, as an alternative, contain a transparent liquid or a lubricant in place of ink. Applications of the latter could include invisible writing, depositing lines or patterns of moisture or chemicals, or applying adhesive in a manner that can be electronically recorded or viewed on a screen.
As is currently the case with optical mice, the surface over which the ball tip moves would be required to have some optically detectable variations (e.g. the texture of normal writing paper). The internal image sensor would therefore allow each continuous path of the ball over a surface to be captured faithfully.
General Usefulness and Application of the Concept
The optical ball pen stylus, as described thus far, would be capable in principle of fulfilling all the functions of an optical mouse—buttons could be added, if required, or clicking or tapping actions could be used, as with various human interface devices that are currently available. If used in conjunction with a computer display, the pointer (or drawing tip) on the display would move whenever the pen stylus was moved while in contact with a surface. The device being in the form of a stylus, the user would have more precise control over the movement of the tip than they would over the movement of a mouse. Also, if the stylus contained ink, writing could be produced on a surface, providing immediate and direct visual feedback, as well as an enduring trace of the path drawn.
However, further innovation would be required if the device were to be given the almost magical characteristic of being a pen that records whatever is written or drawn. Movements while the tip was not in contact with the surface would also require to be recorded, or at the very least the position of the pen stylus would need to be re-established each time the pen stylus was brought back into contact with a writing surface. It would be desirable to distinguish clearly between periods when the pen stylus was in contact with a surface and when it was lifted as part of a movement to the next stroke or line to be drawn. Details of an invention for this purpose are presented in the following section.
Lifted Motion Detection
The making or breaking of contact between the ball pen stylus and a surface could be detected by means of a switch, e.g. the head of the pen stylus could be spring-loaded to allow a very small displacement that would make or break a contact. Devices of this type already exist. Detection of contact-making or -breaking could also be achieved by software, owing to a change of the image of the contact patch, as registered through the light-permeable ball, by the internal image sensor.
Movement of the pen stylus while lifted from the writing surface in the course of use could be detected by means of an array of micro cameras that would surround the tip. The grip of the pen stylus could have equilateral polygonal sides so that there were only, for example, three or six different rotational positions of the pen stylus in the user’s hand. There would then be three or six micro cameras (or an integer multiple of the number of symmetrical grip positions), as illustrated in Figure 5. Irrespective of how the user might rotate the pen stylus, one or two of these micro cameras would provide images of the surface over which the pen stylus was being traversed and software analysis of the images would provide an accurate recording of the two-dimensional lifted motion of the pen stylus. Micro cameras that were not facing the surface being drawn on would not contain images of close surfaces and would automatically be de-selected for motion analysis. Another possible variation would involve a continuous ring camera (capturing an image on a cylindrical or conical or annular band of pixels of an image sensor), rather than a number of separate micro cameras.
Figure 5 Micro cameras for lifted movement detection and a polygonal grip (the flat-sided grip is not necessarily to the same scale as the ball tip)
In another variation there would be only one or a few micro cameras (as a means of providing for optical analysis of the surface under the ball pen stylus during lifted motion) as in Figure 5, but the grip would be shaped to allow only one orientation of the pen stylus in the user’s hand. In that constrained orientation, the camera or cameras would face the surface being written-on or traversed during lifted motion.
It is possible that for some application areas the optical system comprising the ball tip, the compound lens and the internal image sensor might be sufficient to yield adequate data for lifted motion as well as for motion in contact with a surface. This might require a focusing mechanism within the compound lens. External micro cameras would not then be required.
There would be some remaining issues to be addressed, regarding re-establishing bearings, or relative position, where a gross movement away from the writing surface occurred or when it was required to add to previously-written work. On any page or surface two small dots or crosses could be used to define a reference frame. If the optical pen stylus contained ink, these reference marks could be made by the user. A simple protocol could therefore be devised for working with the pen stylus. This would involve placing the reference marks and touching, clicking, tapping, making gestures or hovering with the tip over one or both of the reference marks in certain circumstances to establish or re-establish bearings or, for instance, to start a new page.
Conclusion
The overall concept or invention described here is an optical ball pen stylus that could have many applications, as it would be capable of remembering what it had written or drawn. Through the use of software, diagrams that had been drawn or text that had been written by the pen stylus could be retrieved. In the case of text, handwriting recognition software could yield text documents to be edited further in a word processor. While miniaturization of all the component elements would be a technical challenge, all of the principles involved have already been demonstrated, though not in combination in a way that would constitute the present invention. One manifestation of an eventual product would be a ball pen stylus that would write on paper like a conventional pen and would be capable of recording everything that was written or drawn, without requiring special paper or any other component. The drawings or text could be transferred wirelessly to a computer, mobile phone, smart phone, printer or display screen. I want one of these silly pens that would remember. I just hope it will be very cheap, because I know I’m going to lose it!
Postscript, in View of an Existing Commercial Product
Much of the above was written before I knew of the existence of a similar commercial product. In the descriptions there are some ideas and concepts that are not part of the EPOS-enabled pen from Advanced Digital Positioning Technologies. Perhaps these ideas would have some value either to that company or to a competitor that would like to develop an even better product based on different principles. Manufacturers of ball pens might be interested in diversifying their product range. I could imagine a very low cost ball pen that would remember.
]]>If no new blow-out preventer is to be inserted in conjunction with the slip-on hose then BP will be operating quite a precarious oil pipe that could rupture again in adverse circumstances. When operating with crude oil flowing through it, the pipe to the surface may not have enough self-weight to assure positive engagement with the stub at the ocean floor.
My idea of using a self-weighted taper would be capable of providing a more positive and secure shut-off. I realise, however, that it would be necessary to sever the well riser just below the blow-out preventer to insert it: any such decision should only be taken with extreme due diligence. I do not have enough information to visualise the actual situation: maybe the well riser is not accessible just below the faulty blow-out preventer. Apart from this, because of the force of the emerging oil, it just seems to me that it will be very difficult to place the LMRP. It is my hunch that a long taper could be inserted much more manageably, albeit into full free-flow from the well riser. Of course, any such idea should not even be begun to be physically implemented unless it had first been fully evaluated through computational fluid dynamics (CFD), as has been done by now, I presume, for the LMRP attachment process.
The more engineers who think about these things, and the possible consequences of various actions, the better.
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In the light of the current oil leak in the Gulf of Mexico off the coast of the United States it would seem that not enough engineers thought about how the well might be plugged in the event of such a leak. I was disappointed to learn on TV news that initial attempts to stem the leak have been unsuccessful. The difficulty of working at a depth of a mile below the surface of the ocean is not to be underestimated. I am not familiar with all the technologies that are used, but I could not avoid thinking about the problem over the past few days.
]]> The principle I would use to plug a leaking well would be that of a taper. I would introduce the thin end of a long taper into the broken pipe at the seabed. It would be necessary to apply sufficient force, eventually, to the taper to exceed the full static pressure of the oil over the cross section of the well riser at the level of the sea floor.In order to insert the taper I would place a heavy cigar-shaped weight over the broken well riser. This would serve a number of purposes.
The cigar weight would be supported by a tripod. A gimbal-based mount could be used to ensure that the cigar could be installed vertically. This mount could be designed to allow angular positioning movement while the cigar was supported from above, but would lock in position when the full weight of the cigar was applied.
For ease of fabrication I would make the taper of cylindrical lengths (perhaps of cable, then rod, then water-filled tube) with tapered transitions. The taper would be lowered from the surface and might require the lateral support of heavy guide rings at a number of levels to keep it straight. The weight of the taper itself would be sufficient to allow it to be introduced into the pipe riser.
Before inserting the taper fully (to fill the full bore of the well riser) I might need to carry out some clean-up of the broken end of the well riser. Once I had fully inserted the taper I could lock it to the cigar and then remove the long length from the surface.
This sounds easy. I know it is not.
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Currently, the majority of my colleagues in the Department of Mechanical Engineering would seem not to be in favour of removing an historic Crossley gas engine from the thermodynamics laboratory. A proposal to the effect of leaving it where it is, while making some major changes to the layout of the laboratory, is being drawn-up.
I like that engine. I admire and I value it. However, I find it hard to justify its continuing presence in the thermodynamics laboratory. It has probably not been run for thirty-five years, or, if it has been, it would have been run for only very few hours in that period and for the benefit of very few students. I know for certain that it has not been run since I joined the institute seven years ago. It no longer has the necessary connections to gas and water, so it would now take some effort to get it running again.
]]> Some of my colleagues believe the engine will serve as a showpiece in the, perhaps, not-too-distant future when the institute moves to a new campus. It has been suggested that it could form a center-piece in a new building.My own enthusiasm for the engine falls a lot short of that. I acknowledge that it is an important historical engine. It is in excellent condition and I feel sure that not many of these were built for laboratory use, complete with a water-cooled friction brake and a mechanical device to produce indicator diagrams (plots of cylinder pressure versus volume). It is a true masterpiece of bad engineering.
Yes, I did say masterpiece. The open mechanism on the top of the engine for lubricating the cylinder, one drop at a time, is a marvel. The sheer solidity and massiveness of the engine is impressive. The craftsmanship and attention to detail are excellent. It was not bad engineering in its day: it was leading-edge technology then. The cruel, harsh reality is that if this engine were to be used today it would be bad engineering. The power-to-weight ratio is very low and the efficiency is poor.
The engine is worthy of study and is deserving of a good and suitable home where it would be cared for with a view to indefinite preservation. I just don't see a place for it in a modern thermodynamics laboratory.
As for a suitable engineering showpiece, some of the biggest recent achievements are small low-cost objects such as coronary stents or mobile phones. Perhaps one or two such monuments could be displayed in the thermodynamics laboratory, on a window-sill, without taking up valuable floor space.
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Digital Audio Broadcasting (DAB) became available where I live yesterday. I had given my wife a present of a Bush CDAB5R DAB stereo radio for Christmas in the knowledge that DAB radio transmissions were due to become available. This replaced a Waltham W152 mono transistor radio (FM, MW and LW), which was about thirty years old. The Waltham was a low-cost radio when I bought it and was not of high specification for the time. However, it served without fail and there was never any justification for replacing it as the counter-top radio in the kitchen.
Engineers should be rightly proud of the progress that has been made in radio in thirty years. A single radio station can now be transmitted and received at high quality while using up only a very tiny fraction of the capacity of the airwaves. However, when I experience a product such as the Bush I am not proud to be an engineer. I find the sound quality very tinny and, in fact, there is a buzz at certain pitches in speech and music that irritates me. The radio has a small backlit display for the station name and other broadcast information. This has disappointed me because the text is blurred and difficult-to-read for my 56 year-old eyes, especially moving text on the second row.
The Waltham radio was self-contained and mains-powered, with its transformer inside the casing. The Bush radio has an awkward and heavy transformer plug. It is rated as 230-240v 90ma input for 9v 600ma output, which means that it is very inefficient. Furthermore, it is wasteful of energy if left plugged-in to a live socket.
On the web today I learned that DAB is not forward-compatible with DAB+, which is more efficient and may supersede it, so the Bush is unlikely to serve for as long as the Waltham. Thankfully!