Sunday, November 24, 2013

Tech Talk - The evil in the hearts of men.

It was Edmund Burke who said "The only thing necessary for the triumph [of evil] is for good men to do nothing," and with a hat-tip to Bishop Hill who drew my attention to the testimony, I think I had better say something.

Back in the days when I left school the United Kingdom, and most of Europe, was finally emerging from the brutal impacts of the Second World War. That recovery was helped immeasurably by the coal mining industry where thousands of men labored underground across Europe to ensure that adequate power was available to supply the needs of their various countries as industrial capacity was restored. As an eighteen-year old indentured Apprentice I laid on my back in 20-inch high coal to shovel the 15-tons of my ordained shift onto the conveyor, and braced the roof over my head with hand-sawn timber props to hold it for the following week, as we moved the longwall face forward. I was paid just over four pounds a week, but they did allow me, on Wednesdays, to go to the local Technical College in Ashington where I studied from 8 am until 8 pm. In the good weeks I could then go home, but in the alternate weeks I was either on foreshift, which meant that I went to college directly from the mine, or nightshift, when I went from the college to the mine and worked the following shift. I was woken more than once from an exhausted sleep having fallen into the corridor on the bus. Men died in those mines that I worked in to ensure that Britain had the power that it needed to recover and rebuild.

I thus find myself seriously affronted when this industry (and myself), are called evil by some academic from Oxford, no matter how illustrious his qualifications. In his testimony before the House of Lords Committee on “The Economic Impact on UK Energy Policy of Shale Gas and Oil “ last week, Professor Dieter Helm said
Of course one would want to make sure that regulators are on top of any environmental consequences that might flow from drilling, but I find it truly extraordinary that people want to ban fracking in a context where they are not prepared to ban coal mining, and indeed across Europe actually promote coal mining. When one thinks about the relative environmental impacts of the alternatives, coal mining is truly evil in comparison. I find it extraordinary that people are legally allowed to mine coal if you want at the same time to have a blanket ban on shale gas extraction.
It is almost a throw-away line, a necessary genuflection to the politically correct views of the day, a glib reference to transient effects long recognized and ameliorated by the coal industry over the past decades.

In those days of my youth, back in 1962, I walked into Newcastle to take the first bus of the morning from the terminal to the mine some 11 miles away at Seghill. It drove past pit heap after pit heap, and the impacts that Professor Helm is I believe referring to were real, and evident. The mine I worked in was over a hundred years old, and my father had been manager there when my brother was born. You walked stooped for part of the way to the face, since the roof of the passage was low, though the temperatures were pleasant, year round. Coal moved by conveyor and mine car, once hand-loaded from the blasted face, and supplies came in on carts hauled by pit ponies – another unforgettable memory. Hundreds of men worked at each mine, with a typical stint being a 10-yard length along the 200-yard measure of each longwall. We were not evil, the industry was not evil – it was vital and necessary. And it has changed.

Instead of walking there are now mine cars that haul workers to the face, electric trams have replaced ponies, and machines now do the work that muscle did back in those days. Where then is the evil? Is it that we are removing material from the ground? But unless you wish to go back to human densities of 70 people per hundred square miles of the hunter:gatherer era this must happen, for if they aren't grown resources must still be mined from the earth.

Yes there are transient effects, but if instead of dwelling on the ugliness of the excavation on some cold wet day when the shadows are right to emulate some hellish landscape, one were to go back five years after the mine has moved on (presuming that this is some surface site) then those wounds from current mines have gone. Laws require, and company self-interest demands, that land be restored. In parts of the world that can realize unexpected benefits as the land becomes more productive than it was before. You can no longer find much negative evidence of the underground mines in the area I worked in.

But the intent of this post is not to pat myself on the back, nor to run off on a rising rant, but rather to point out a problem which this broadly prevalent and stridently negative attitude is generating. Early this morning I received a call soliciting funds for the Footsteps Program at the University of Leeds, where I was awarded my degrees. But I had to gently break it to the young student calling that I could not participate because the University had done away with the Mining Engineering program through which I obtained my degrees. Further they have turned over the building, donated to the University by the industry and its workers for such studies, to the Art Department.

Leeds is not alone, the Royal School of Mines, merged now into Imperial College, London no longer offers mining courses.. The Welsh School of Mines, now the University of South Wales, no longer offers mining courses – there is but one place in the UK, at what was Cambourne School of Mines but is now the Penryn campus of the University of Exeter, where such a course still exists.

This image of the industry as an evil entity is ironic given, as Professor Helm pointed out:
Practically now, in Europe and the UK, we are switching from gas to coal. We have gone from about 28% of our electricity generated by coal a couple of years ago to about 40% today. Germany is bringing 7 to 8 gigawatts of new coal on to its system. Coal stations are being built across eastern Europe. The coal burn generally has gone up across Europe. Germany has gone from nuclear to coal and from gas to coal. This is a really serious environmental development across Europe.
For many years the rational pursuit of energy policy in many parts of the world was hindered by the demonization of nuclear power. It has taken that industry many years to work through the opprobrium that hindered realistic discussions of costs and benefits, and it is only now that some of the green community are beginning to recognize the irrationality of some of their earlier arguments. Yet the vilification of that industry cost it an entire generation of management and engineers who were persuaded to avoid such a career and who starved the industry of a strong supply of graduates. Now that engineers are needed there not that many with long experience, since the generation running the industry is retiring.

And here we are seeing a growth in the demand for coal, and yet – in part because of the demonization of the industry – there are but limited places where qualified engineers can be found, and at a time when advanced levels of technology will be called for as deposits get leaner, deeper and more difficult to extract there are even fewer places that can carry out the needed research into excavation technology.

Sadly academia and government seem to be unwilling to face the reality of the future that these circumstances will bring. Because the situation cannot be reversed in a year or two, as the knowledge base fades (as it now rapidly is) so it will become harder and harder to meet global needs. But no doubt academia will find a way to blame that on us miners, the few of them that will remain.

Someone told me once – “if you want to find gratitude, you’ll find it in the dictionary, between chump and sucker*.” But, one might have thought that for those who claim to predict the future, perhaps the occasional thought of self-interest might burble its way through, but not, I suppose, at Oxford.

*the statement has been modified for a general audience.“

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Waterjetting 15c - Surface quality

In the beginning, when the very name of waterjet cutting was, in itself enough to create an interest, the quality of the surface that was left after the jet passed was not a critical factor. The surface was, relative to other techniques, left in a cold condition without the imposition of additional stresses brought about by the cutting process. This, in itself brought some benefits to the use of this new tool, and when melded with the benefit of a continually sharpening blade, meant that there were a wide variety of applications where it had an immediate (in not so quickly recognized) benefit. One of these was in the cutting of food products. Here, where the aesthetic need for a sharp clean-cut surface could be joined with the reduced crushing along the cut line, provided an increased appeal both in immediate and longer-term to the use of a plain waterjet system.

Back in the days when we were all trying to find new ways of using this new tool, I remember colleagues from the National Research Council in Canada commenting about relative trials in cutting peaches. The problem with mechanical cutting of freestone peaches is that the knives occasionally hit the stone, distorting the cutting edge and, over time, making for a ragged cut. In looking for alternatives, the NRC compared laser cutting with that of a high-pressure waterjet system. With the laser there was this strong smell of burning, a relatively wide cut appeared on the surface, but the high water content of the flesh of the peach inhibited further cutting. With the waterjet, in contrast, the cut was cleanly and effectively achieved within the necessary time. The cut was clean, and without the compression of fibers that would, otherwise over time lead to discoloration and customer dislike. More recently this same result has led to the widespread use of waterjets in trimming, for example, the lengths of celery that are found in the grocery sections of many stores.

Cut edge quality is thus an important issue when it comes to selling the benefits of this new tool. But edge quality means different things to different customers. To aircraft manufacturers that we have worked with, being able to cut through half-inch thick titanium with a precision of 0.001 inches over the alignment of the cut was a critical problem. In cutting the walls of the Omnimax Theater under the Gateway Arch in St. Louis we were asked to maintain the wall alignment, over its fifteen-foot depth, within an inch of vertical. (Which turns out to be a precision of 0.005 inches per inch, not that much greater a tolerance than that we provided in the aircraft application). In cutting through the granite to make the Millennium Arch the concern was more to ensure that when the central figure was completely outlined that there would be no protrusion that would stop the two parts of the piece being separated.

In traditional processing, it is common to expect that, after the pieces of an assembly have been separately cut out, that the part edges will be finished separately, before the components are brought together in final assembly. Thus, as an example, after using a cutting device to cut the shapes of different parts of an assembly, secondary finishing is built into the cost and time schedule to allow for this additional step of cleaning up the edges of the parts to remove the cut imperfections that form as a part of conventional cutting.

But, in many cases, the use of an abrasive waterjet system does not require that second step. The quality of the initial surface cut is well within the bounds of precision and accuracy that are required to meet the final assembly part requirements. As a result there is at least one, and often more steps that can be eliminated from the assembly schedule, and the costs for those set against any additional costs that the waterjet cutting costs might have initially brought into the overall picture. In assembly costs time is money, and the elimination of steps in a process can be significantly greater than just those occurred in the process itself. It is an advantage that is not often fully recognized.

Consider, for example, the simple case where two surfaces are to be riveted together. In the older, conventional practice the two parts would be mated one to the other, while a machinist came along and drilled the rivet holes through the two parts. The parts would then be separated while the burrs and machining residue was removed from the two pieces separately, and then they would be relocated and re-aligned, and a riveter would then come along and drive in the rivets to hold the parts together.

In contrast, where an abrasive waterjet is used the tool can cut through both (or more) parts without burring on the edge, leaving holes of high enough edge quality that there is no burring or need for subsequent re-finishing. The rivets can be immediately installed in the appropriate holes, which are already aligned and ready, and two lengthy and costly process steps can be saved.

As a trivial issue, but one of increasing importance as the cost of raw materials increases, the component pieces that are cut from the solid to make the two parts can also be recovered as a single piece, with the opportunity for use in another application, rather than being rendered down into scrap that must first be reconstituted in to a solid piece.

To continue with the analogy (though it is admittedly a bit hard to find a secondary use for metal of this shape) the metal removed from the rivet hole can be recovered in a single piece.

Figure 1. Rivet hole metal removed from a sample as a single piece, compared with the conventional alternative.

There is, however, one caveat to this discussion, and that relates to surfaces that will be precision welded after cutting. One of the problems that abrasive waterjets can create, is the occasional embedment of the abrasive particles within the cut surface. (Figure 2).

Figure 2. SEM image showing abrasive particles embedded in a surface after cutting. (Dr. Galecki)

Where this is a possible problem then the simple answer, as my colleague Dr. Greg Galecki has demonstrated, is to repeat the cutting path but with a high-pressure waterjet along feeding over the cut surface (at a higher traverse speed). This removed the buried pieces and leaves the surface in the condition required.

Figure 3. SEM image of cleaned surface showing a representative site where the embedded particle has been removed.

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Tuesday, November 19, 2013

Tech Talk - Employment Opportunities

In 1961 I started my career as a Student Apprentice in the National Coal Board in England, going on a year later, under a National Coal Board Scholarship, to the University of Leeds, where I studied for both my bachelor and doctoral degrees. As I recall the NCB had authorization for 100 scholarships a year, but rarely awarded more than a few (I was the only one at Leeds in my year). By the time that I received my second degree, in 1968, the writing was on the wall for the British Coal industry – folk I knew with 1st class degrees were finding work as face deputies, with continual reduction in pit numbers making promotion beyond that point hard to anticipate. When I mentioned an offer from America the folk in the Personnel Office suggested that I would be wise to take it.

When I came to the USA the coal industry was also in a bad way. Coal prices were low, and the market very competitive. As a consequence there was little interest in mining research, and student enrolment in Mining totaled around 40, for the four-to-five year course that we offered for undergraduates at the time. Numbers in fact were so low that I was asked to teach in another department, since we did not have the numbers to justify the classes in Mining. And then along came the first Oil Crisis.

Suddenly we did not have enough room, with individual classes rising to enrolments of up to 50 students. Colleagues were teaching three separate lab classes for the same subject to meet the demand. As an anecdote of the times I remember going to a Mining Conference in Pittsburg and, at the dinner, being asked what I wanted to drink, when I asked for Scotch I got a bottle – of a quite expensive brand. This continued through the beginning of the 1980’s and we were learning to accommodate the larger numbers and adjust to having some financial security in our funding. The only problem was that we were finding it hard to attract students for graduate school, since job offers were multiple and lucrative. The market was good both for coal mining and in the metals side of the house (gold, lead and other minerals). (It was in this interval that I was named the second Curators’ Professor of the campus, following, inter alia, our development of a novel mining machine).

And then Saudi Arabia re-opened the taps, and the price of oil fell, and suddenly there was a glut of coal on the market. Suddenly we were faced with highly qualified graduates calling back to see if they could get into graduate school, enrolment began to shrink rapidly as word got back to the high schools about the poor employment prospects. Those of us seeking research funding were driven to look beyond the discipline of Mining into other applications of the technology, if we were to be able to find funding. We got a new Dean early in that time, and I rather suspect that there was not a year over his decade or so of tenure that he was not faced with cutting the school budget. One year the Mining class was down to an enrolment of one student for his year, and talks of mergers and dissolution were in the air.

But then the price of oil began to rise again, coal markets began to grow, both nationally and abroad, and metals prices also began to rise. And we slowly grew back up to, and currently beyond our previous records for enrolment at the beginning of the 80’s. Salaries and opportunities have grown and, since we now recruit more actively abroad, even with a strong domestic demand for graduate students, our graduate program has also surged. Faculty work-loads have also grown, and with the odd retirement or move elsewhere there has been a shortage of qualified faculty, and only limited time available to develop new research programs, despite new levels of funding.

And yet, just as the schools become complacent with their new prosperity, there are signs that we have perhaps passed the current peak, and may well be heading into the next cycle of down and then up. The writing is now yet that deeply inscribed into the walls, but there are some worrisome trends that today’s Department Chairs are, no doubt, already well aware of.

In the United States the TVA has just announced that it is moving away from the use of coal in its power plants. The goal is to reduce the share that coal provides to electricity production from 38% to 20%, while raising the amount generated by renewables from 15.7% to 20%. It is intended, over time, that a third 20% will come from natural gas, and nuclear power will make up the total to 100%.

The impact of this, and similar decisions being made at power plants around the country, is already evident. The EIA, in their November Short-Term Energy Outlook, has noted that employment in the Kentucky coal industry has fallen 24% this year. And while the fall in production is, as yet, not that great, with exports currently failing to pick up the decline, the future is, yet again, not that promising.

Figure 1. Trends in US Coal Consumption (EIA)

At the same time there has been a little wobble in the gold market. Barrick Gold Corp. the largest gold mining company, has seen its stock stumble over the past year.

Figure 2. Price of Barrick Gold stock over the past year (Forbes )

Currently traders are anticipating that the price of gold will have to fall below $1,200 an ounce before demand will rekindle.

These are, perhaps as yet small straws in the wind, yet even as the global economy continues to struggle upwards I suspect that the lot of the Mining Engineer may soon be a little more complicated than it has been for a while. This last surge in employment and opportunities saw the end of my generation to a large extent, so that we have been replaced with a much younger crop, since the intervening management layer was not formed, since there was neither the demand nor the supply available in those lean years to create such a layer.

And yet it is unlikely that the future will be as bleak as we saw in the 60’s and 80’s. The predictions of vast resources from shale gas to help many countries meet their energy needs have not yet proved to be real. In the meanwhile, as the Polish experience indicates governments have to ensure that their constituents have adequate fuel supplies at a reasonable cost – and for many countries that means a coal future – even if, as in Poland’s case, they have to start importing it to keep up with demand.

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Monday, November 18, 2013

Waterjetting 15b - Making the Millennium Arch

At the time that we carved the Missouri Stonehenge, our abilities seemed limited to cutting only linear passes through thick blocks of rock. However, while this has an application in the quarrying industry there are also many applications where contour cutting to depth would find a market. We were challenged to demonstrate this when it became time for the MS&T campus to find a project to mark the Millennium.

Figure 1. The MS&T Millennium Arch by Edwina Sandys The piece is in two parts, the Arch in the foreground and the extracted figures form a second grouping near the building entrance.

As a little bit of a back story, Winston Churchill had come to Missouri in 1946 where he gave his “Iron Curtain” speech at Westminster College in Fulton. This led, inter alia, to the National Churchill Museum. At that time Scott Porter, a Rolla minister’s son, had gone up to Fulton and took a color photograph of the visit. Skip forward past the fall of the Berlin Wall and Westminster College had commissioned Edwina Sandys, the internationally recognized artist and sculptor, to create an appropriate sculpture to mark that event. The sculpture, "Breakthrough” was formed from pieces of the Berlin Wall that had been cut by a hand-manipulated abrasive waterjet nozzle to silhouette a male and a female shape, and to quote the sculptor:
In Breakthrough, from the blank former–Communist side, you see light through the male and female shapes, and when you walk through to freedom, from dictatorship to democracy, it’s as if you were living in a black-and-white world, and now you’re in glorious Technicolor.
At the Dedication Scott presented a copy of the photograph to Edwina, and they got to talking – long story short – the campus asked her to create a sculpture for the campus, funded by Scott as a memorial to his parents, and I became her “hands” in helping to carve “The Millennium Arch.”

Figure 2. Breakthrough, a 32-ft high sculpture on the Westminster College Campus – carved with a hand-controlled abrasive waterjet (Edwina Sandys)

By the time that the sculpture was commissioned the granite quarries in Missouri had re-opened and we were able to acquire three blocks of granite from which to carve the five pieces of the sculpture. One of the advantages of waterjet cutting, as both Breakthrough and The Millennium Arch illustrate is that the “cut-outs” are removed entire, and can thus become figures in their own right. The figures from “Breakthrough” are at the Roosevelt Library in Hyde Park, NY, forming the “Break Free 1990-94” sculpture.

Once the blocks had been brought to Rolla we decided to move them indoors, something we had to do manually as we wanted to continue cutting through the winter, and because the computer driven table that John Tyler and our students designed and built would be better protected inside. (Though we had forgotten that debris from the cutting would have enough energy to reach the roof). The blocks weighed around 35-tons each, and the first task was to trim the edges of the two legs of the piece, to a rectangular shape. Stepping motors were used to move the cutting lance along the first four sides of each block, then the pieces were moved outside and gently allowed, with timber block support, to fall over onto their sides before being returned to trim the last two sides.

Figure 3. Cutting the edge of a Millennium Arch leg.

Figure 4. Before and after picture - the block on the right is about to enter the cutting table, while that on the left has been trimmed to size/

Figure 5. Block laid flat under the cutting table. to allow cutting of the male figure (in progress). Note the heavy plastic sheet strips used to protect the bay.

The heavy plastic strips shown in figure 5 are heavy enough to absorb the energy of the flying debris from the cut, while being flexible enough that they will deform swaying and deflecting, rather than being cut themselves.

After the design had been finalized (we had cut a 1/12th scale model followed by a half-scale version to check the dimensions as we re-learned how best to cut this granite) the blocks were cut using the same concept of twin, spinning jets issuing from a dual orifice nozzle, and rotating at 90 rpm. Because the Missouri granite is stronger than the Georgia granite, the cutting pressure had to be raised to 20,000 psi. The granite was not as consistent as that of the earlier Stonehenge, and harder inclusions inside the rock were more difficult to detect as they slowed the cutting rate, requiring a closer monitoring of the cut to ensure that the nozzle was not fed forward too far in successive passes.

We had thought about the possibility of making the cuts through the granite using an abrasive waterjet cut, however single pass cutting would have been incredibly slow, and a test using a multiple pass system with a single non-rotating nozzle showed that after a couple of inches of cutting that the edge quality was beginning to deteriorate. With the prospect of this getting worse in depth, and the need to separate the two part of the sculpture after the cut this led to the decision to use the plain waterjet system that we were familiar with. It did mean that the figures ended up two-inches shorter than the holes they came out of.

As with the earlier Stonehenge the slots were cut in the block by traversing around the path one time, and then lowering the nozzle a third-of-an-inch and then repeating the pass. The slot was roughly an inch wide, to allow for variations in the crystal sizes on the edges of the cut, and to allow the nozzle to move around all the contours of the geometry.

Once the internal figure had been released from the surrounding leg we had to separate the two pieces. It was easier to slowly jack the outer leg up, first one end then the other. the narrow gap between the pieces restricted the tilt we could make on any one lift, but it took less than an hour to get the leg high enough that we could slide the figure out.

Figure 6. Raising the leg so that the cut figure of the female can be slid out from underneath, after which the leg is lowered back onto rollers to remove it from the frame.

The surface quality of the three Arch and two figure pieces had then to be adjusted. The surface was hand-polished for the inner surface of the legs and the figure surfaces. The rough cut crystal-outlined surface was first ground flat using special graded grinding disks, and then the final polish achieved with the industrial polishing disks. While it took 22-hours to cut out a single figure from a leg, it took us two months to grind the surfaces, which could have been done faster had we mechanized the process. Hand polishing was a poorer selection that I made at the time.

There were two additional problems with surface texture – the sides of the legs appeared too “regular” after cutting and still showed the striations from the individual passes down the walls. To overcome this problem we used a hand-held lance, at 20,000 psi, to retexture the surface, and this turned out to give a relatively natural –looking surface.

The capstone gave a different problem, since the intent was to make it appear as a natural shape, and yet it was, as delivered, very clearly shaped by the splitting wedges that had separated it from the massif. Again a hand-held waterjet was used to smooth some of the sharp corners and provide a rough contour for the piece, while the secretarial and other staff in the RMERC (Vicki Snelson, Diane Henke et al) helped mix up our own brew of glue and granite chips to fill some of the splitter holes left in the block.

Figure 7. Dr. Galecki re-contouring the capstone for the Arch.

The two vertical legs were erected, and then a template taken identifying their exact position. This was then set against the underside of the capstone, and two pockets were milled out two-inches larger on each side than the leg sizes. When the capstone was then lowered onto the legs these pockets allowed the legs to penetrate six inches into the capstone, and provide some additional stability to the stones.

Before the capstones were set, however, it was noticed that the waterjet finishing of the surface of the legs had shown where there were two weakness planes within the legs that might, in the millennia that follow, fail. To prevent this from causing the Arch to collapse three holes were drilled down through the legs, and carbon rods anchored and post-tensioned through the possible weakness planes. Carbon rods were used to prevent the problems that corrosion might otherwise, in later years, cause to the sculpture as metal might expand and fracture the rock more that support it.

(Those of us there then autographed to tops of the legs, before we set the capstone on them.)

After the capstone was in place the gap between it and the legs was filled with the same glue:rock chip mix that had been used elsewhere to fill undesired holes.

The two figures were installed on a separate plinth, some 50-ft from the Arch itself, and these two were anchored in place with carbon fiber rods that extended up from anchor points in the plinth through the lower legs of the figures.

The Arch was dedicated in the Fall of 2000, in the presence of both Scott Porter and Edwina Sandys.

Figure 8. Arch Dedication ceremony, Scott Porter is escorting Edwina Sandys, while I follow with Chancellor John Park.

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Saturday, November 16, 2013

Travel complications persist

In 1785 Robert Burns wrote a poem to a mouse, the last-but-one verse of which reads:
But Mousie, thou art no thy lane,
In proving foresight may be vain:
The best-laid schemes o' mice an' men Gang aft agley,
An' lea'e us nought but grief an' pain, For promis'd joy!
So it sometimes seems with my recent post history since, yet again, I find myself away from home without the resources that I need to complete this week's posts. Since they have largely been prepared I crave, again, your indulgence with the intent that they should appear within the next few days. My apologies. The rest will follow.

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Sunday, November 10, 2013

Tech Talk - Energy cost, additive engineering and cavitation

I paid $2.85 for a gallon of gasoline this weekend, at the gas station just up the road from our house, here in South Central Missouri. A couple of weeks ago while I was in the UK the price my brother paid was around $8.00 a gallon. The BBC calculator that I used to check the UK price tells me that I am paying $6.89 less per tank than the regional average here, and that were I to live in Italy my tank-full would have cost me $95 more, while it Venezuela it would have cost $43 less. (It cost $45 to fill my tank).

The low cost of fuel is one of the benefits from the increased crude oil production in North America, sustained as it is by the increase in production from Saudi Arabia to balance the global market losses from other countries around the world. Further the EIA explains the refineries are helped with this low price by the high demand for diesel and the premium that it has achieved – causing refineries to run at record levels to meet the demand, and producing, as a secondary product, more gasoline that is thus being marketed at the lower price. It is a situation that the EIA expects to continue for a while.

Figure 1. US refinery inputs (EIA TWIP Nov 6, 2013)

The relatively low price of fuel, here in the United States, particularly relative to Europe is starting to attract industries historically located abroad. The move to date is being led by those attracted by the cheap price of natural gas, particularly in the chemical industry. BASF, for example, cut the ribbon last week on a plant expansion in Vidalia, LA and just recently announced plans to expand its research facility in Beachwood, Ohio.

It was, however, another report on manufacturing that really caught my attention this week. It was the news that 3D Printer technology had advanced enough to now make a gun from metal parts. The process involved is somewhat more complicated than that used in earlier guns manufactured using this new generation of equipment. Earlier in the year a gun had been made from plastic parts and made some additional news when a version fired nine shots without falling apart. The evolution of the plastic gun is worth noting in that the first one reported was built from components printed with an $8,000 second-hand Stratasys Dimension SST 3D printer. And while it fired a shot successfully, the gun blew up on the second trial. The second gun, however, was made on a $1,725 Lulzbot A0-101 3D printer, that was available from Amazon, made by Aleph Objects and it survived firing nine rounds. For a variety of reasons the plastic gun contained some metal parts, but it marked the advent of this new technology. Prices for these replicator units are already down below $2,000 and they are limited, at present, to working with different types of thermoplastic. (But they can make, for example, shoes.)

The difference in being able to move to making parts from metal, particularly those that allow the repeated (over 600 times) firing of the gun is a very significant step forward. Thirty-four parts were made from stainless steel and Inconel 625 and then a grip was made from nylon, using a classic 1911 design.

Figure 2. The metal gun made by Solid Concepts (Solid Concepts )

It is the different metal part of this that is worth underlining. The components were made by laser-sintering (which simplistically means that they used a laser to melt tiny particles of metal so that they would fuse together to make the model). The machine that is used to do this, at the present time costs between $400,000 and $1,000,000. It also has power and other logistic needs that require it be run in a commercial, rather than residential environment.

But, as Sold Concepts notes:
Solid Concepts has been using metal sintering for some time now to successfully create parts for a wide array of products. The 1911 gun is well known and people can relate to it in respect to its power and need for precise components. This story is about how additive manufacturing can be used to produce real, accurate parts in your industry whether it’s aerospace, transportation, medical, energy, consumer products, etc.
The changes that this will make in industrial manufacturing, and in the global market for materials cannot be underestimated. At present parts are generally made by subtraction, taking large billets of material and milling and machining away all the un-needed bits, producing large volumes of scrap chips. None of that waste will be generated with this new process.

Chris Hechtl has already produced The Wandering Engineer” series of Science Fiction books, starting with New Dawn that uses the concept widely as one of the bases for the stories. (Worth a read just to get some idea of the scope of what is to come - though I am also enjoying the series, as the books are written).

It is going to change the way in which components are built, but it will also change the way in which minerals are processed once they are mined from the earth. It will be no longer necessary to cast metals into large ingots and then forge them down into smaller shapes. It is likely that, for many items in the near future that process will still be cheaper, but as time progresses and the costs of the process reduce (bear in mind that this is laser-based and remember how those costs have come down as lasers have become ubiquitous in society) that even large parts may be better made this way. Further it allows intricate melding of different materials to make products that are stronger and better suited to the need.

Thus the objective of mineral processing in the years to come will be aimed at making fine powders rather than going through all the steps to make the larger ingots. That will, in turn, impact earlier stages of processing, and, while I don’t normally discuss my own work in these posts, I would draw your attention to a recent post from October 31st, down below, which includes a video of a small piece of equipment virtually instantly breaking half-inch coal into 5-micron pieces, which can be done with a pressure washer from the local hardware store. It also works in breaking out minerals from their host rock.

The world indeed will change, and with those changes the power requirements of the future are also going to undergo drastic revision.

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Wednesday, November 6, 2013

Waterjetting 15a - Carving a Stonehenge

This post is a marriage of two different themes that have recently appeared at Bit Tooth. The first, under the Waterjetting title, has contained a discussion of the different aspects of high-pressure waterjet use. The second, more recent theme discussed both the original Stonehenge and then how the MS&T Stonehenge, which is a working calendar, functions. In this post I am going to talk about how the MS&T megalith was built, and since it involves the use of high-pressure water it seems appropriate to include it in the Waterjetting Series.

As I have noted in one of the earliest waterjetting posts we had learned, from Russian literature, back in 1966 that waterjets could be used to cut into granite. From results of an unplanned test, we had learned that the pressures needed to cut through granite need not be that high. Others had predicted that it would take a jet pressure of up to 30-times the rock compressive strength in order to penetrate rock efficiently. However both the Russians and ourselves had been able to drill through a 30,000 psi granite with a waterjet pressure of only around 10,000 psi, rather than the predicted 900,000 psi.

We had done this by moving the jet over the surface so that, as the jet passed across the cracks between grains, so it would penetrate and pressurize the crack, causing it to grow and remove the grain, without having enough pressure to cut through the grain itself.

Figure 1. 9-inch thick block of granite drilled through by a 10,000 psi waterjet at Leeds University. It took over 30 minutes. (Summers, D.A., Disintegration of Rock by High Pressure Jets, Ph.D. Thesis, Mining Engineering, University of Leeds, U.K., 1968.)

We had drilled this block of rock back in Leeds and the nozzle was pointing vertically downwards, as we rotated the rock beneath it. After drilling a shallow central hole, we stepped the nozzle out a short distance and repeated the process, breaking the outer ring of rock to the central core. Then after widening the hole, we could come back to the center and advance the nozzle into the rock, and repeat the process. Because of the nozzle size we had to continually step the hole to a smaller diameter as the hole got deeper, and thus there is a rapid taper to the walls.

Moving forward to the early 1980’s when Chancellor Marchello asked Dr. Marian Mazurkiewicz and I to cut the rock for his Stonehenge, and we knew that we could cut the rock at a pressure below 15,000 psi (the size of the pump that we had at the time). But tests where we had made multiple passes over a rock had shown that, with a direct vertical cut to an edge, that repeated passes would taper the cut inward over time – naturally doing what we had done artificially at Leeds.

Figure 2. Early tests on granite cutting. Note that the lower cut was made with two jets diverging at about 5 degrees, and the one above it with the jets diverging at 11 degrees. (The nozzle was spinning and moved across the face of the rock several times).

These tests showed that we needed a higher angle to ensure that the sides did not taper, and while this could be achieved with the nozzles angled at 15 degrees to the perpendicular, because the jets had to cut a path wide enough for the nozzle to enter the slot, an angle of 45 degrees was used after a short series of experiments.

Our team at the Rock Mechanics and Explosives Research Center (RMERC) had been asked to carve the rock, since we had just prior to the commission, been down in Georgia demonstrating to the granite industry there that waterjets were able to economically cut granite.

Figure 3. Starting to cut a 1-inch wide slot in granite, pressure 14,000 psi, 90 rpm, linear cutting speed around 9 ft/min, areal cutting rate around 20 sq. ft./hour.( Raether, R.J., Robison, R.G., Summers, D.A., "Use of High Pressure Water Jets for Cutting Granite," 2nd US Water Jet Conference, Rolla, MO., April, 1983, pp. 203 - 209.)

Concurrently with showing that this could be economic we had also shown that the technique removed the respirable dust from the air that is generated with a flame-torch cut, and that the noise level would drop to industrially acceptable levels from the “jet engine roar” of a cutting torch.

Figure 4 Showing the flame at the bottom of the burner spalling its way through the granite.

Figure 5. Cutting granite with a flame-jet lance, Graniteville MO 1979. (Note the cloud of very fine particles of granite being blown out of the right side of the slot).

The first thing to do in arranging to cut several hundred tons of granite was to find a source of supply. Unfortunately, at that time the granite quarries in the South-East part of Missouri were closed and other sites in the state did not prove practical. But because we had done the work with the Elberton Granite Association in Georgia, we were able to arrange to purchase rock from one of the Quarries around Elberton, Ga. They themselves had recently constructed their own version of the standing stones, the Georgia Guidestones although these had been cut to shape using flame jets, rather than water.

Figure 6. The Georgia Guidestones, Elberton GA.

The granite blocks were roughly split to shape in the quarry, and then shipped to Rolla by train. The first block was sent by truck and this proved the benefits of rail, although the size of the cars limited the scale of the monument to half that of the original in the UK. Which meant that the blocks – over 11 ft tall – were one-eighth the weight of the originals.

Figure 7. Blocks of granite in the cutting frame. The cutting lance is the thin rod in the center of the picture.

The blocks were brought to the RMERC and placed in position using a crane. Dr. Mazurkiewicz and his students had built this frame from wooden blocks, with the guide rails made from radio antenna mast. The lance moved on a cross-beam, also made from radio antenna mast. The low reaction force from the jets meant that the forces on the structure were very small. Thus the head itself could be pulled along the track using a bicycle chain, and small, fractional horse-power motors could be used to move the head and advance it into the slot. Although, by that time, self-rotating heads had been developed, it was decided that a better control of the cut edges could be achieved if the head was hydraulically rotated.

Figure 8. Detail of the cutting platform. The two hoses feed a hydraulic motor that gear-drives the rotation of the cutting lance. The high-pressure water feeds through the hose to a small swivel at the top of the lance. A small electric-motor driven screw behind the platform elevates and lowers it on the guide rails to advance the nozzle into the cut.

In order to keep the slot width as narrow as possible the nozzle holder was made as small as the feed pipe, with the two jets issuing from small carbide inserts within the holder.

Figure 9. Detail showing the nozzle holder and a nozzle orifice on the lance.

Experiments showed that an effective cutting rate of around 20-square feet an hour (depending on the direction of cut relative to the planes of the granite) could be achieved. The lance was rotated at 90 rpm, and moved down the cut at a speed of 9-ft per minute. The two jets, at a pressure of around 14,000 psi (there was some pressure loss in the system) would cut into the rock around 1/3rd of an inch on each pass, and the lance would be lowered this amount after the pass, and then the direction reversed and the jets would cut back along the rock. (This is somewhat faster than the hand-held stone flattening of the original Stonehenge rocks in England, although studies in Peru, where a similar technique was used to shape to blocks that build Machu Picchu showed that it is possible to flatten about 1 square foot an hour once you learn how to chip the rock). Professor Parker Pearson has also noted that the UK original had the rocks finally shaped after they had been erected).

Figure 10. Showing the jet arrangement, raised after a side had been trimmed so that the jets could be seen. Normally with the jet in the cut there is little to show the cutting action.

It took about a morning to cut one side of a block (or in later stages to cut one of the large blocks in half for the smaller stones). Once the second side had been cut, the block was turned and the rail aligned to cut the third and fourth sides. Overall, given that the operations had to be shut down during the winter where the temperatures were below freezing, the blocks were cut and completed over the course of two semesters, largely working with undergraduate student labor.

After the blocks were cut, they were taken to the site, where each was placed in position using a crane. Because of the precision required to align the blocks with the sun, this was a time-consuming operation. The major standing stones were then held in place with an additional pour of 18-inches of cement. (They stood on a cement platform).

Figure 11. Lowering a block into place.

The monument was dedicated at the Mid-summer solstice in 1984, with John Bevan, a Druid of the Gorsedd performed the dedication.

Figure 12. Speakers at the Dedication: Dr. Joe Senne – who designed the megalith; John Bevan – Druid; Dr. John Carlson – from the Center for Archaeoastronomy; Dr. Joseph Marcello – Chancellor.

The construction was sufficiently novel that it was awarded one of the ten Engineering Awards from the Society of Professional Engineers.

(Note there is a video of the construction available on DVD. This shows, in part, that the jets can trim an edge without any material on one side, something other tools find difficult, because the nozzle does not contact the rock). There are also other articles that I have written answering some questions and describing the site on the RMERC web page.)

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Tuesday, November 5, 2013

Iceland's Earthquake patterns

Every so often I look at the earthquakes that occur, as a regular part of life, in Iceland. In recent months they seem to have a more regular focus along the lower edge of the rift that is slowing pulling the country apart, and since the current crop ends at the Mýrdalsjökull crater, I suspect it will continue to draw my attention.

Figure 1. Earthquakes occurring in the last 48 hours in Iceland. The star denotes one bigger than M3.

Nothing to be alarmed about, just interesting to note how this shows the separation markers that will ultimately lead to more significant events.

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Sunday, November 3, 2013

Tech Talk - of Alaska, Libya and the belated bleat of awareness of a problem

I have written in earlier posts about the problems that the Trans-Alaskan Pipeline System (TAPS) will face, as production declines below 500,000 bd. The conclusions from that post are pictorially summarized in a graph in the recent edition of the Oil and Gas Journal.

Figure 1. Declining throughput through TAPS showing the points of concern (OGJ)

Looking at current figures, in September the pipeline had an average throughput of 524,181 bpd against the year-to-date average of 528,092 bpd. It has just passed below the upper limit at which operational difficulties can be anticipated, due in part to the flow being too slow to keep the temperature high enough to prevent wax from separating from the fluid, and starting to block valves and critical infrastructure. Because of the long lead times, and high capital requirements for the development of new fields in the Arctic, and the likely probability that these will not yield significant production until at least 2025, the article is pessimistic about both the fate of the pipeline, and future Alaskan production.

Despite those declines OPEC remains optimistic, in their October Monthly Oil Market Report that the world producers can continue to meet global demand as they foresee it rising to an average of 89.7 mbd this year, and then going up to 90.8 mbd on average next year. They foresee, for example, that non-OPEC supply will increase this year by 1.1 mbd (to 54.1 mbd) led by production gains from the USA, Brazil, Kazakhstan, South Sudan and Sudan. Next year they see an additional non-OPEC growth of 1.2 mbd with Canada replacing Kazakhstan among the five countries that will make up this additional production. In contrast OPEC itself is reducing production, with overall production reported to be down 390 kbd in September.

The gain in crude oil production seen in the US, which has risen from 5 mbd to an average of 7.3 mbd in the first seven months of this year has had a significant impact on these projections, though the change in the mix of product now available to the Gulf refineries will continue to have some impact on the overall import picture. This is because, as the EIA note, some of the heavier crude refineries along the Gulf are tied to foreign producers including Pemex of Mexico, PDVSA of Venezuela, and Saudi Refining (for a combined total of just under 2 mbd).

Yet it remains difficult to sustain the optimism that OPEC project. Libyan exports, at one time running up around 1.25 mbd remain down at some 90 kbd, due to tribal disruptions and internal political disputes that show little sign of resolution.

Figure 2. Recent Libyan oil production (Energy Policy Info)

Certainly the physical ability to return to around pre-disruption levels has been demonstrated, but the weakness of the central government does not indicate that the political problems will be resolved in the near future. And until they are there is the best part of 1 mbd being with-held from the market. This drain from global supply is not yet disruptive since it has, to date, been largely picked up by the Kingdom of Saudi Arabia (KSA).

The picture from the combination of Sudan and South Sudan following the division of the one country into two has not been promising, however it appears that the overall total decline has now been halted, and recent reports have raised production to somewhere between 190 kbd and 240 kbd.

Figure 3. Change in oil production from Sudan and South Sudan following the division of one country into two. (Council on Foreign Relations )

The IEA is not optimistic that the return to production will be as smooth as others think:
“Industry sources have been quoted as saying that restarting oil production could take six months or even longer, since the lines have been filled with water and because some wells were not closed properly.”
The OPEC projection that overall Sudanese production has returned to the 240 kbd level may, therefore, be still an optimistic estimate. The increase to 175 kbd following the repair to the pipelines from the Majnoon field in Iraq is encouraging (although the high level of violence that continues in that country does not give high confidence that the pipeline might not be struck again.)

The increased production from the Kashagan field in Kazakhstan – anticipated to rise to 75 kbd - has again been hit following system leaks so that this increased production that OPEC had anticipated has, again, been postponed.

And while production has now started from the Espirito Santo in the pre-salt fields off Brazil, it is not clear whether the production gains will offset the declines that have occurred in Brazilian production in recent months.

Figure 4. The Espirito Santo floating production storage and offloading (FPSO) vessel (Shell )

Just as there is a perception that the United States is heading toward independence in energy needs (a fallacy I have written about several times in the past), so there is a perception that OPEC is becoming a less critical supplier. This is far from the case. KSA has been producing over 10 mbd for the last months, in order to offset the loss in Libyan oil to the market, and the combined production of KSA, UAE, Kuwait and Qatar now supplies 18% of global demand. This is only the second time that this number has been that high in the past 30 years. It comes at a time when the Middle East is supplying 25% of Chinese oil demand, as that country passes the United States to become the largest importer of oil.

Figure 5. OPEC oil production (numbers compiled from secondary sources (OPEC MOMR October )

This comes at a time when the world still wonders about the actual oil balance as it flows in and out of China.

Unfortunately the picture that is emerging continues to show that OPEC is tending to be overly optimistic in its forecasts for production, which does not bode well for future supplies of fossil fuel.

Given that a group of environmental scientists have just released a letter calling for increased investment in nuclear power since, to quote James Hansen:
Hansen, who’s now at Columbia University, said it’s not enough for environmentalists to simply oppose fossil fuels and promote renewable energy.

“They’re cheating themselves if they keep believing this fiction that all we need” is renewable energy such as wind and solar, Hansen told the AP.
This comes a bit late, since as I noted recently, it takes over a decade to build a new nuclear power plant, and with the current schedule for existing plant closures moving inexorably along their timetable, this may presage a decade of power shortages. We shall see!! But in the meanwhile we had better hope that those folk concerned over the possible shut down of the Trans Alaskan Pipeline because of inadequate flow are being just a tad pessimistic.

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