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It was a few months ago that Scienceray took a preliminary look at the momentous construction project going on near the Hoover Dam – you can see it here.  Then we saw how the project began in 2005 and we left it in June of 2009.  At that point the arch was more than fifty percent complete and it was hoped that the two sides would meet in the fall.  That is in the here and now, so let’s take a look at how the project has progressed since then.  Have the hopes of the bridge builders come to fruition?

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All attention since June has been focused on the arch that will underpin the road that will connect the States of Arizona and Nevada.  Certainly, it seems to be painstaking work and the work literally seems to inch towards completion.  Not to worry, though.  The folks of the two neighboring States are patient people – after all the Dam itself is close to celebrating its seventy fifth birthday.  Those who remember its grand opening back in the Great Depression are now octogenarians.  Still, the near completion of the arch is cause enough to fly the flags, even though there is a painstaking six feet still to go. Look at this great shot from the completion day in August, however.

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If you look to the right of the flags – about ten meters or so, you will see a tiny figure with a safety hat and orange coat.  That’s one of the construction workers and gives an idea of the sheer scale of the project.  There is no doubt that those working on the project must not be afflicted by bouts of vertigo – however occasional.  Would you want to be up that high?  Just to put it in to context, it is over two hundred and fifty meters down from this height.  As Shaggy might say, yikes.

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Talking of things (rather than people) in their eighties, the bridge is now eighty five percent complete.  The arches have been connected.  Earlier in the year the contractors had finished work on the steel tub girders and the deck on the spans and the first segments of each arch were cast.  The very last sections of the arch were connected on 27 August 2009.  After this the supporting cable system had to be removed and this took a further two weeks.  The arch became free standing and self supporting on 27 August. 

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There is more work to be completed.  This includes setting the precast columns and erecting the steel girders.  What is most important, of course, for those who will use the bridge, is the casting of the roadway itself – both the deck and the barriers.  From road level, the archway is nearing completion in July.

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It is still July and the arch is nearing completion.  Although there is a month to go before their removal, the supporting cable system is still in place.  What a tragedy it would be if the cables were to give way at this point in time – the whole construction would plummet in to Lake Mohave like the denouement of some James Bond movie.  Fortunately, the brilliance of the engineers and the construction workers would pay off.  By August the arch would be free standing.

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So, when visitors are allowed on the bridge, what will the view of the Hoover Dam be like?  The picture above gives you an idea, taken from the bypass bridge itself.  Breath taking is quite the word.

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The next part of this piece contains photos from the actual bridge itself taken on the day that the arch became free standing – August 27 2009.   The bridge itself is huge – but it is close to the dam – around five hundred meters all told.  If you want the full name for the bridge then you must refer to it as the Mike O’Callaghan-Pat Tillman Memorial Bridge.  Could we not call it the M&P for short perhaps?  O’Callaghan was the Governor of Nevada back in the nineteen seventies and a Korean War veteran.  Tillman too was a veteran, but of the Afghanistan conflict where he was killed in action in 2004, his death surrounded by more than a few conspiracy theories.

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The bridge on the day the arch became single.  If you look between the two spans you will see another worker, crouching on a platform.  Again, this gives you a sense of sheer scale but, rather more interesting (to Science Fiction fans, at least) is the small blue box on the center right hand side of the picture.  Could it be that a certain Time Lord is thwarting another attempt by evil alien invaders to launch an attack on the earth from the Hoover Dam?  Or is that just what construction workers, taken short, refer to as a room called rest?

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This shot gives a really good feeling of how high the actual bridge will be when it is completed.  As you can see, the bridge will not be slim, exactly.  It is a new section of Highway 93 and as such will have two lanes each way over the complete span of five hundred and seventy meters.  A stagger inducing two hundred and fifty six meters above the river at its base, the bridge will not, however, afford drivers a view of the Hoover Dam as they cross.  It is way too high for that.  They will, however, be able to park and walk across the entire span should they wish, pretty much where the workers are on the left.

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Now the arch is complete there is almost another full year of work to be done to complete the bridge.  That will include the construction of columns on the arch itself that will eventually provide support for the roadway (see second to last picture – work has started).  Overall the statistics are very impressive.  About twelve hundred construction people have worked on the project with a further three hundred engineers.  The bridge is not the only feat of engineering – the four miles of four lane highway (which doesn’t in itself sound too impressive) was very difficult because of the rugged terrain that surrounds the area on all side.  The highway on its own cost over twenty million dollars.

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This picture of the Hoover Bypass Bridge was taken from Lake Mohave by boat in September 2009.  You can clearly see how the supporting cable system has now been removed and the arch is now free standing.  This marvelous image captures the sheer scale and grandeur of the project and proves that sometimes, when it comes to photography, looking up is just as effective as looking down.

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However, the view from the heavens is just as remarkable.  These shots were taken from a passing United Airlines flight to Las Vegas.  A breathtaking view from September 13 2009, the project can now be easily imagined complete.  Scienceray will return for the opening of this amazing bridge – hopefully in November 2010.  Watch this space.  For now, in October 2009, we say goodbye to the bridge.  As you can see, the pillars which will support the bridge road are now being built from the arch itself.  Amazing.

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Let us finish here, however, with a gorgeous high definition shot of the Hoover Dam Bypass Bridge taken in October 2009.

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You may Also Like: The Incredible Hoover Dam Bypass Bridge Under Construction (this site)

Ferguson states that the field of engineering is moving in the direction of simplification, where the deciding factor is not the user’s experience, but rather lets the software do much of the work that would otherwise have been done by the engineer. This approach, however, lets the programmer who writes the software make those decisions for the engineer, and like the engineer who does not realize the capabilities of the materials he is working with, he is prone to make decisions that are not the best informed, making assumptions, which in many cases lead to purely arbitrary choices. While convenience is a fact of life in the modern age, simplification and the taking away of user decision-making only limits the possibilities, and forces thinking in a certain direction. In any case, there are many ways to accomplish a single task, while there is no one method that is the best in every aspect. However, there is a solution that is the best for a given situation, and that is up to the judgment of the engineer.

Furthermore, Ferguson also states that the entire process of design is not flexible enough. Sponsors for certain projects must be presented with a preliminary plan, which is often arbitrarily constructed. Ideally, the components required for a certain project would be designed and tested first, and then the big picture adjusted as needed. However, when the finalized framework has been decided before the design process even begins, there are bound to be problems that could not have been foreseen. However, these undertakings are generally sponsored in part or in its entirety by the federal government, who has nearly infinite resources, which it derives from its taxpayers. Since the project is too large to fail, the solution is to throw more funding at an unsound design, which due to a lack of flexibility, contains several fatal flaws that cannot be easily fixed.

Given Ferguson’s perspective, a plausible solution to the problems posed by these gaps in the engineers’ training would be to include at least some machine shop experience in courses taught to engineering students. Having an idea of the limitations of the materials and the machines used to work them into the desired shapes would allow for better judgment in this area, and could mitigate design defects based purely on flawed judgment and assumptions in the place of careful calculation. Having the projects themselves more open to change and the process built in a more flexible manner would allow any problems that do arise to be circumvented. There are many ways to tackle a specific problem, as stated beforehand, and if one particular method does not work as well as expected, these engineers should be prepared to work in a new direction if necessary, rather than doggedly pursuing a directive that may not be achievable at all. Methodically, they should be versed both in design, and physical application of these designs, and they should not be dependent on computer-automated tools that require them to follow a set of built-in limitations, dictated by the boundaries of the software. They should be aware of how to operate the tools and systems they design, so as to allow for better usability, and so they will keep in mind that their final product must be practical. Philosophically, they should be taught to think independently, outside of conventional constraints. Rather than blundering through any errors they encounter, they should be taught to mitigate those issues in advance, or work around them when they arise.

Overall, Ferguson emphasizes that most engineering failure is not from miscalculation, but rather from misjudgment and a lack of calculation. Given a new mindset of not guessing on details, but rather taking the time to check all their numbers and doing the math to make sure that in the real world, they can be as sure as possible that their design will work. While the engineer, somewhat like the artist, puts form to the raw materials, he must also be able to think in the material, physical, practical sense when he creates a design, because unlike the artist, who only puts out his design as the final product, the engineer must make sure that what he designs can perform in the real world. He must also understand and take into consideration how his design will operate, and be able to understand also the individual components so he can modify and change their configuration, or even their very makeup if needed. He must be aware of not only its form, but also its function.

And while many engineers reject art as being something different from their own work, as being more abstract and “soft” than the “hard” practice of engineering, every engineer must also consider the aesthetic side of his work as well. These are arbitrary decisions in most cases, though sometimes a few have been able to apply form as a part of function as well, though this is something of their own genius, rather than something that had been taught to them while they were still taking their courses in graduate school. However, even if aesthetics are not taught to them during their courses, this is something that they must encounter regardless, and to leave this solely to their uninformed, and consequently arbitrary decision would be that otherwise avoidable errors from faulty judgment would appear in the framework of these projects. Artists, in their work on aesthetics typically follow a set of rules, laid down by whichever school of thought they associate themselves with. However, they are only limited by the application of their medium, and aesthetic rules are easily broken in the artistic scheme, whereas the engineer is limited by natural law, by the laws of physics, which cannot be broken as easily, if at all.

However, in terms of amplitude, the range of perception cannot be quite so succinctly stated. As with the other senses, when the values are close to the lower threshold of possible perception, small variations can be picked up quite readily, though at higher levels, the variations that can be picked up become larger by powers of 10; it is possible to detect even small changes in volume when listening to a whisper, but that same change at a high volume would be imperceptible. The scaling of decibels indicates this; every 20 decibels shows an increase by a power of 10 in amplitude of the air pressure fluctuations (Möser 5-6).

In terms of volume, the range perceptible by the human ear goes from 0 dB to approximately 140 dB. At the very lowest threshold of volume, vibrations of less than the diameter of a molecule in the eardrum are still picked up by the brain, but at the upper threshold, it is not a matter of the sensitivity of the ears, but rather a matter of damage to the nerves in the inner ear, as well as the tympanic membrane. While the ear can be exposed to volumes of over 120 decibels for short periods of time, long term exposure to sounds of volumes of over 80 decibels can cause permanent hearing loss and hearing disabilities. The hair cells inside the cochlea can be killed off, and when their numbers are decreased, the sensitivity of the ears to sound is lessened (Smith 351-355). Aside to physical damage to the middle and inner ear, excessive sound, even below the threshold of 80 dB also has a psychological effect on people. Sleep and relaxation is disrupted, and conversation and telecommunication is made difficult, causing irritability and stress, and stress related diseases (Burke 87-96). Therefore, reducing noise is something that must be considered.
For the most part, passive noise control systems, or systems that just reduce the volume of sound overall are in use in the present day. One example of such a system is mufflers, which slow the speed of explosive exhaust coming from the engine, thus reducing the volume of the sound created when the hot gases are released into the environment. Soft paneling on walls is often used to absorb sound as well, and an example of passive noise control that is limited to a single person is earplugs, which dampen pressure fluctuations. While such systems can be quite effective, and are for the most part easy to produce, one major disadvantage is that they cannot selectively filter noise. When such systems are in play, all sound is dampened, not just unwanted noise. In 1934, a patent for an active noise control system was granted to Paul Lueg. It described a method for cancelling sound by using a loudspeaker to emit a sound that was exactly out of phase with an existing sound in the environment so that any bystanders nearby would not perceive that sound (Lueg 1-2). Such a system would be useful for cancelling out predictable, constant frequency noise, but when random bursts of noise are introduced, this simple method of active noise cancellation cannot cope.

In the present market there exist several personal active noise cancelling devices, the most widely known are the noise cancelling headphones produced by the Bose corporation. While these are generally able to reduce low frequency, common background noise by around 20 decibels, and consist mostly of a microphone attached to the headphones that sends a signal to a computer that compares the input sent from the microphone to the desired output, for example, an audio file that is being played by the device, then emits the difference between the two in such a way as to cancel out the undesired noise. Its first practical application came from a need for hearing protection in the field of aviation, where in the 1980s, plans were being made for the first non-stop aerial circumnavigation of the world. In the cockpits of the planes, noise levels peaked at over 110 dB, and while earplugs and other passive noise reduction systems were effective in blocking out chatter, they were less efficient at canceling out the low drone of aircraft engines. (“Escape the Noise”).

A similar concept is popping up in architecture and other design in the form of active vibration control. When such structures are swayed by the wind, or some other force, accelerometers measure movement in each of the three degrees of freedom, causing weighted pendulums come into play in order to cancel out the vibration caused by that force. In this case, the problem faced is slightly easier, as wind and other stresses are often constant. However, noise control can add to this application, as reduction of noise leads to the dampening of vibration. As sound that would normally pass through a structure is removed from the environment, those air waves no longer cause that structural to shake. This method is used to allow submarines to operate more quietly, and to prevent material wear caused by the vibrations (“Active Noise Control”).

However, the effectiveness of such systems is limited by the computers and algorithms that essentially predict incoming noise, and emit an inverted signal in time to cause interference in the sound wave. Since sound as a whole is the sum of many sine waves, existing systems for predicting incoming noise utilize the Fast Fourier transform, an algorithm that computes a Discrete Fourier transform, which generalizes a series of sine functions with a common period using discrete values (“Fast Fourier transform”). Using this method, the computer is able to identify a certain tone coming in, as well as its overtones, and collectively cancel out that entire sound, but the user is still left exposed to random noises that cannot be summed up as periodic. Non-continuous sound, such as the clicking of keys when typing on a keyboard, or unwanted conversation is still let through. While more efficient algorithms are being developed to make the current approach of filtering out constant, periodic, repetitive noise faster, but in order to gain more application, a system of detecting incoming noise in real-time before it reaches the listener, then emitting the correct inverted signal is necessary to achieve this desired noise control in all situations. However, given that the microphones used in active noise control systems are inches (in active noise cancelling headphones) to feet (airplane cabin systems) away from the listeners, there can only be a delay of milliseconds between intercepting the sound, processing, and delivering the proper inverted signal. This may be possible in non-mobile systems first, as space for computing electronics is less limited, and the delay allowed is slightly larger, but as computing technologies improve and shrink, real-time detection and cancellation may prove possible in personal headphones everywhere.

Works Cited:

Möser, Michael. Engineering Acoustics. Berlin: Springer, 2004.

Smith, Steven W. The Scientist and Engineer’s Guide to Digital Signal Processing. San Diego: California Technical Publishing, 1997.

Burke,Richard E. “A Model of Community Noise Pollution.” Simulation, 27.3 (1976): 87-96.

Lueg, Paul. “Process of Silencing Sound Oscillations.” US Patent 2,043,416. 9 June 1936.

“Escape the Noise.” Bose Learning Center. 30 July 2009 http://www.bose.com/controller?event=VIEW_STATIC_PAGE_EVENT&url=/learning/escape_the_noise.jsp

“Fast Fourier transform.” Wikipedia, The Free Encyclopedia. 29 Jul 2009, 21:59 UTC. 29 Jul 2009 http://en.wikipedia.org/w/index.php?title=Fast_Fourier_transform&oldid=304963063.

“Active noise control.” Wikipedia, The Free Encyclopedia. 15 Jul 2009, 12:28 UTC. 15 Jul 2009 http://en.wikipedia.org/w/index.php?title=Active_noise_control&oldid=302214828.

Although there are pills, potions and age-old recipes designed to ease the symptoms of this distressing condition, there has never been an effective cure.  However, in I868 an inventor named Henry Bessemer believed that his latest invention would solve the problem once and for all.

Henry Bessemer was born in Charlton, Hertfordshire, England, on the 19th January 1813 and, like his wealthy father, he too became an inventor.  Amongst other things, Henry became the first person in the world of steel-making to invent the process of mass-producing steel.  He also found a way to compress plumbago dust to make ‘lead’ pencils, which he sold to a friend for around £200, and produced brass powder to use in pigments in place of gold.

Unfortunately for Henry, like Horatio Nelson before him, he suffered badly from seasickness, which caused him much distress as he often had to cross the English Channel to conduct business in France.  With this in mind he set out to invent a cure.

As an engineer he was well aware of the concept of how a ship’s compass stayed level in use, regardless of how much the vessel pitched and rolled, and knew that if he could apply this principle to the cabin of a ship, the world-wide problem of seasickness would finally be resolved.

In the garden of his home in Denmark Hill, London, he constructed a working model of his design, whereby a cabin was supported by a system of gimbals making it totally independent of the outside walls; or what in reality would be the main structure of a ship.  Putting the model through a series of tests, simulating the effects of wave action at sea, he was delighted to find that the model responded well.  Encouraged by the results the inventor decided to go into full-scale production of his design – the Bessemer Saloon.

In association with ship designer, Edward James Reed, he had the Bessemer Saloon installed within a converted cross-channel, 4-paddle steamer.  The swinging saloon was 70ft in length and 30ft in width and was furnished sumptuously in the Victorian style of the time.  Large gilt mirrors adorned the walls, potted plants were placed at strategic points and thickly padded leather seats were provided to add to the air of elegance and luxury.

Finally the day of truth had arrived, the ship was ready to undertake its maiden voyage, and Henry Bessemer was ready to prove to the whole world that he had invented the cure for seasickness!

In 1875, on a private voyage with invited guests and investors only, the SS Bessemer steamed out of the safety of Dover harbour and headed across the English Channel for France. 

Everything seemed to be going well, until the ship approached the French port of Calais.  What Bessemer could not have foreseen during the trials with his garden model, was that at slow speed the action of the swinging cabin made the vessel virtually uncontrollable; a fact that hit home in more ways than one when the paddle-steamer collided with the wooden pier at the entrance to Calais harbour.

Undaunted, and confident that his invention would work, Bessemer returned to England.  Hasty repairs were made to the ship and on the 8th May 1875 – on a voyage available to members of the public – the SS Bessemer once again steamed across the Channel towards France.

Due to the fact that full repairs could not be made in the time allotted between voyages, the saloon had to be locked in place during the trip across the Channel, which to anyone’s mind would have made the whole trip rather pointless! 

The result of the ‘locking-in-place’ of the saloon was to have a devastating effect on the stability of the ship.  The pier at Calais was about to suffer again!

As the vessel slowed to a crawl and the wooden pier crowded with onlookers drew nearer and nearer, the SS Bessemer began to roll about alarmingly, totally unresponsive to the steering operations of the helmsman.  Within minutes the ear-splitting sound of splintering wood rose above the cheers of the crowd as the ship rammed into the pier, it knocked down a large number of supporting pillars and left the whole structure in an extremely dangerous condition.

In his autobiography, Bessemer recounts the collision with the pier.  “We had arrived – very slowly, it must be admitted – at the entrance of Calais harbour.  I, knowing what had occurred on a previous occasion, held my breath while the veteran Captain Pittock gave his orders to the man at the helm.  But the ship did not obey him, and crash she went along the pier side, knocking down the huge timbers like so many ninepins!”

Following these two chaotic incidents, the investors who had pledged capital for the project quickly disassociated themselves from the whole affair.  Henry’s dream of overcoming the scourge of seasickness, and seeing a fleet of ships containing a Bessemer Saloon crossing the oceans of the world, evaporated.  The SS Bessemer was consigned to the scrap heap in 1879 and remained rusting in a Dover dock, never to sail again.  

But, this was not the last that would be heard of the Bessemer Saloon!

When the SS Bessemer was eventually broken up, Edward James Reed who had been closely involved with the doomed enterprise stepped in to save the saloon and had it transported to his home, Huxtable House in Swanley, Kent, where it served for many years as a private billiard hall. 

When the house later became the Swanley Agricultural College, the saloon was pressed into service one again – this time as a lecture hall. 

So, had Henry Bessemer’s innovative design at least been saved for posterity?  Unfortunately not!

In a sad twist of fate, the story of the Bessemer Saloon came to an abrupt and undignified end in World War Two – it was destroyed by a direct hit from a German bomber flying over Kent.

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A 2008 shots gives the imagination something to work on. As the Hoover Dam became more and more popular with tourists the local roads began to get more congested than people could really put up with.  Their solution?  Harking back to the huddled masses days when America really was considered to be the land where everything was super-sized (and not just the fast food) the good citizens of Arizona and Nevada decided to build a bridge.  Not just any old bridge though, this one would have the longest concrete arch in the US. The arch would ultimately be finished in August 2000 – and you can see it in its entirety here.

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In 2007, the tower structures, these known as approach spans, are beginning to take shape.  It is known, in the briefest of terms as the Hoover Dam bypass and this much is true.  There will be seven approach spans all in all, two on the Arizona side and five on the Nevada side.  The bridge is enormous, but its proximity to the dam is less than half a kilometer.  The longer, more proper and formal name is the Mike O’Callaghan-Pat Tillman Memorial Bridge.  Perhaps it is already known as The Mike and Pat locally. O’Callaghan was the Governor of Nevada in the nineteen seventies as well as a veteran of the Korean War.  Tillman is by far the more controversial choice.  He gave up a millionaire lifestyle and superstar footballer status to serve in the US Army in Afghanistan where he was killed in 2004.  His death has been subject to military investigations and more than the occasional conspiracy theory.

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Back to 2005 and the bridge is in its infancy.  It has a way to go, even yet, in its construction, even though the most recent pictures see the span almost conquered by one of the most amazing engineering feats of our times.  It will cost a pretty penny, of course; estimates have it at upwards of two hundred and fifty million dollars.  Patience, however.  Try and resist the urge to scroll down and take in the images, if you… too late.

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It won’t exactly be a slim bridge, either.  It and the other new sections of Highway 93 will have two lanes going each way over its five hundred and seventy five meter span.  It may not be an idea to look down either if you suffer from vertigo.  The road itself will be a dizzying two hundred and fifty six meters above the Arizona River.  Although people will still be able to park and walk across it (if they dare) drivers will not be able to see the Hoover Dam.  It is too close and too below to be seen by them.  The project suffered a serious setback in 2006 when four cranes collapsed.  This caused a massive two year delay while the project recovered.  It is now back on track and the next in this series of articles can be found here.

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At night, in 2008, the construction work seems like some vast drawbridge in to some dark post apocalyptic fortress.  Behind it, the Hoover Dam. Iconic as the dam is, the bridge itself will become an important route between two equally iconic American cities, Phoenix in Arizona and Las Vegas in Nevada.  Since the Dam’s completion both cities have seen their population sky rise (perhaps the bridge is a good metaphor for the burgeoning number of their citizens). 

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By April of 2009 the bridge begins to look like a bridge – not to state the obvious.  Suddenly, in the space of months a real shape begins to emerge.  It looks as if plans are on schedule for the bridge to serve as the successor to the old road.  Highway 93, which was as good as highways got back in 1935 is simply too old and, well, curvy to be adequate in this day and age for twenty first century traffic.  Plus of course, it only has two lanes (that is counting both directions).

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A closer look at the arches gives the onlooker a greater impression of the sheer scale of the project.  Take a look at the moveable platforms where brave people perform their duties each day.  A certain day in the September of 2001 made things worse for those who rely on the original road across the dam as a transport link.  After the air attacks on the American mainland, no trucks have been allowed over the dam for fear they could be packed with high explosive.  Instead the trucks have been sent south to a crossing near Laughlin (on the Nevada side).  More disruptions, albeit for a very good security reasons.  When you figure that there will be almost twenty thousand cars and trucks using the new bridge every day the enormous costs – and the security concerns – begin to make a lot of sense.

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Let us take to the air to see the bridge from a real vantage point and ponder the simply awesome highlights of the project.  To begin with it will eventually take the removal and embankment of over three and a half million cubic yards of earth.  The bridge itself will be made from two hundred and forty three million tons of concrete.  The steel used to reinforce the concrete would, if put on a set of scales, weigh sixteen million pounds (some set of scales!).  Plus it has brought many, many jobs in to the area, with over twelve hundred people being involved in its construction.

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June 9, 2009 and the arch edges even closer to completion.  The arch is more than fifty percent complete and it is hoped that the two sides will meet in the Fall of this year.   Below, even more recent on June 18.  What kind of party will be held on the day the two parts of the arch meet is anyone’s guess, but it is likely to be the biggest since the end of Prohibition.  It can only be hoped that none of the revellers gets too tipsy and ends in the Arizona River.

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It is hoped that the bridge will be complete some time in 2010.  When it is complete it will look like something out of the space age (oh, shucks, yes, that’s our era after all).   The impression below, with no disrespect to the artist (but one suspects he once worked for Gerry Anderson), gives away little of the grandeur and majesty that the final, finished bridge will possess in (millions of) tons.

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The next in this series of articles, which covers July – October 2009 – when the arch becomes free standing can be found HERE.

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This was considered one of the marvels of the twentieth century when it was built and even though its size and energy generating capacity has been surpassed it is still possibly the most famous and iconic dam in the world.  It was completed in 1936 and still has a gothic cum deco inspired feel to it which renders it art while many other dams simply have utility.  It is named after President Hoover who has an instrumental role in its construction.  It has been a national historic landmark in the United States since 1985.  Its statistics are impressive as well – it is two hundred and twenty one meters high and has a thickness at its base of two hundred meters (fifteen at its crest).  That is quite a lot of concrete.  Over a hundred people died in its construction including a father and son – JG Tierney a surveyor (popular history maintains he was the first person to die).  His son, Patrick W died thirteen years to the day later and is purported to be the last to die on the project.

Grande Dixence – Switzerland

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Switzerland is by no means the largest country in Europe but its gas the highest on the continent.  Its job is to hold back a lake – the Lac des Dix – and when full it is almost a thousand feet deep and contains more than four hundred million cubic meters of water.  As for its altitude, how about an amazing 2365 meters?  Strangely enough, the river upon which it is built is pretty small (the Dixence).  However, water is collected in to a system of tunnels over one hundred kilometers in length which takes water from the river and from others.  The water is mostly from glaciers.  Filled in 1957, this current dam submerged the previous one which had stood since the nineteen twenties.

The Karun Dam – Iran

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Whether or not you agree with the aims of the Iranian government to join the nuclear club (ostensibly to help with the massive power shortages of this populous nation) there can be no argument in terms of their attempts to meet the power demands of the country.  The massive Karun 3 opened in 2005 and it does indeed go a long way to satiate the demand for electricity.  It is just over four hundred and sixty meters in length and stands at a height of two hundred and five meters.  It is an arch dam, which is perfect for that rocky, narrow gorge in which it was built. The curve is more than just an aesthetic feature – the arch forces the water to press downwards against the dam.  This strengthens its foundations.  Simply amazing.

Dworshak Dam – USA

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Construction of the Dworshak dam began in 1966 and it was completed only six years later with the generators up and running in 1973.  It was built in the state of Idaho about six kilometers away from the city of Orofino.  It is the highest straight axis dam in the western world and at two hundred and nineteen meters in height is the third tallest dam in the United States.  The reservoir that was formed behind the dam is over eighty kilometers in length.

The Inguri Dam – Georgia

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Georgia is well known for being the birthplace of Stalin (by now you will have guessed we are not referring to one of the United States) and this dam was built at the height of Soviet engineering.  Although started in the early sixties it did not become functional until the nineteen seventies.  This notwithstanding, the dam is still the highest concrete arch dam in the world.  It reaches two hundred and seventeen meters which is an astonishing eight hundred and ninety feet.  With the collapse of the Soviet Union, when borders within the USSR were not really a problem, this dam found itself (still) inside the borders of Georgia.  The hydroelectric power station, which is serves, however, is partially in the Republic of Abkhazia.  Abkhazia and Georgia do not get on very well at all.  Oops.

Nagarjuna Sagar Dam – India

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Built across the Krishna River in the Andrha Pradesh area of India, the Nargana Sagar towers at one hundred and twenty four meters in height and is able to hold almost twelve million cubic meters of water.  This makes it the largest dam in Asia – at the moment.  It is also one of the oldest.  Construction began in 1956 but it was a long time before it became fully functioning.  Modern construction equipment was not available in the fledgling democracy of India and so the dam was built with stone instead of concrete.  As you can imagine this took some time and it was not until 1969 that the dam was completed and three years later that the crest gates were fitted in order to facilitate full usage.  Up to seventy thousand people took part in its construction, with close to two hundred dying in dam related construction accidents.

Srisailam Dam

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We will stay in India – and indeed the Krishna River, for now to visit the Srisailam Dam.  It is part of the same project to bring hydroelectricity to the millions of people who live along the river and beyond.  It is built in a huge gorge in the Mallamala hills and is over five hundred meters long.  It may seem to be over icing the cake, but when you realize that the region in which it is situated is extremely prone to drought you begin to understand why size is sometimes important.  Although this image is not perfect it is one of the few copyright free photos available of this dam – special permission is needed to go near it.

Glen Canyon – USA

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The stunning landscapes of Colorado provide a back drop for the Glen Canyon dam, which is build on the Colorado River in Arizona.  As might be guessed by the surroundings, the place is arid and the mission of the dam is to provide water storage for this particularly dry part of the United States.  It stands at two hundred and sixteen meters high and the crest of its arch has is four hundred and seventy fie meters long.  It has been criticized for the environmental impact it has had on the local flora and fauna but sustains large communities of people spread over three states. 

Vajont – Italy

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One hundred kilometers north of Venice there is the Vajont Dam, which was finished in 1959.  One of the greatest dam tragedies of all time occurred in 1963 when the overtopped and a massive flood wiped several villages below the dam off the face of the earth and killed more than two thousand people.  An enormous landslide fell in to the reservoir and displaced fifty million cubic meters of water.  The wave that overtopped the dam has been estimated as over two hundred and fifty meters in height and the people below did not stand a chance.  It has been cited as one of the five worst man made disasters (caused by geologist and engineer failure).  It stands a more than impressive two hundred and sixty two meters high and is twenty seven meters thick at its base.  Ironically when the dam overtopped it was itself left pretty much intact – only the top meter or so was destroyed.

Sayano-Shushenskaya – Russia

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Ah, those Russians!  The power plant that this dam supports is the fourth largest in the world and it was opened in 1978.  Another example of the gravity arch dam, this one has a crest of almost eleven hundred meters in length.  The arch itself is two hundred and forty five meters height.  The dam itself forms a reservoir of the same name, which covers over thirty cubic kilometers and a surface area of over six hundred square kilometers.  That is large, by any standards.

Almendra Dam – Spain

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Salamaca, Spain is the home to the Almendra dam.  It was named after the village of Almendra (which means Almond in Spanish) but, as with many of life’s little ironies, it interrupted the course of the river five kilometers away from the village.  The reservoir behind the dam covers almost ninety square kilometers and this makes for a breathtaking view.  At a height of just over two hundred meters it is one of the tallest structures in the whole of Spain.

Itaipu – Brazil

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The Itaipu dam of Brazil is given its name from a small island that used to exist near the site and it means “the sound of a stone”.  One can only imagine what the dam sounds like when it releases its water.  The length of the dam is a staggering 7235 meters and at its highest it is two hundred and twenty five meters.  To be fair to the other dams on this list, however, it is actually three dams joined together to make one enormous structure. 

Three Gorges Dam – China

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Although China has many of the world’s largest dams their reluctance to allow people to take pictures of them means that its most famous and accessible – the Three Gorges – is the only one to make this list.  To facilitate its construction one and a quarter million people had to be relocated.  Although spectacular it is thought that it has contributed greatly to the functional extinction of the Yangtze River Dolphin, a creature which had been around for several million years.  With a final look at the Grande Dixence, at what price, we can only wonder, do all these amazing structures come?

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The screw as envisioned by him was rather a spiral put onto a cylinder. It was tightly fitted into a tube. Putting one end into water and the other on dry land, it could be used to pump water upwards over short distances simply by turning the screw by hand. Such devices are used to this day in the Middle East by farmers watering their fields.

The screw is also widely used in modern machines. Powered by electricity, you might find them anywhere in the world. They are used in water irrigation systems, water drainage systems, where sludge has to be moved, or for upward transport of powders and dry corn type materials.

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These days, power technology rediscovered the old man’s screw to produce electricity. In a reversed principle, the water flowing downstream is forced to run through an Archimedean screw. The screw is turned by the force of the water and the end result is electricity.

British Heritage owns a power plant dating from 1909 at Linton Falls in the Yorkshire Dales. It was decommissioned in1948 and has been preserved for the sake of being one of the first power plants in the country. Now it will be fitted with two such screws to produce 510,000 kilowatt hours of electricity per year.

As the river Wharfe is a small watercourse with no spectacular gradient, this could prove to be a future source of energy for many countries around the world. The screws are wide enough to let fish through unharmed should they get caught in it. There is no need to build a dam and thereby no restriction for fish from going upstream. Such a power plant could be built on almost all little rivers that carry more water than a trickle.

Besides Archimedes there were many other Greek, Roman, and Arabian thinkers who came up with energy efficient ways of doing things. History is a good teacher, and it may be hoped that more scientists will feel the need to copy old wisdom.

Out of the many possible careers involved in this science, I chose to research the profession of robot technicians. They can, if you will, give the robot its very “life”. A robot technician designs robots, which involves months- possibly years- of tedious work with blueprints and raw materials. They also test robots to make sure all of their hard work is functioning properly. Technicians then install these robots into whatever service, building, or company that may have a demand for them. Over time, the robot may develop problems or malfunctions. This is also the duty of a technician. He or she may need to replace or clean the broken parts. Although usually the job of a programmer, sometimes this duty falls on the technician as well.

Many people with this career are hired by the robot manufacturing companies because of their knowledge of specific robots. Over time, the technician may have gained enough experience in specific robots to teach lower level employees about them. If the technician has just begun working in this field, he can earn a salary of $21,000 to $31,000. More experienced workers that can earn between $40,000 and $50,000.

The requirements to become a robot technician include completing high school, followed by completing two years of training by a higher level employee. It is also recommended that robot technicians are skilled in science and mathematics. Of course, a desire and interest in this field helps as well, as it is constantly changing and developing.

Robotics has taken an amazing turn in our society in the past few years. We have now begun to allow humans with one or more of their limbs severed to still use that arm or leg! These life-helping machines are called manipulators because of an amazing scientific breakthrough that allows the human mind to actually manipulate the arm much in the same way someone would use their own arm. This is also a perfect example of where different careers can intersect. The robot technicians career is now falling into the career of medicine. As doctors and technicians continue to discover more ways to improve their practices, this will happen more and more.

Robot technicians, like many other careers, may involve promotions. If technicians show good leadership and good understanding of the science, then they can be promoted to a robot trainer. One of the tasks of a robot trainer is to teach a class about a specific robot that the students may specialize in. Then the trainer may be asked to drop their current occupation, or possibly be promoted to a robot programmer. After that, programmers could become the head of the robot facility because of their experience, leadership, and general knowledge of robots.

More and more we are seeing robots in our daily lives. Promising turns have brought upon “thinking robots” and robots that will listen to your every word. Robot technicians also are used here. As stated before, sometimes robot technicians are asked to become robot programmers. When making these “thinking” robots, robot technicians have their work cut out for them. They have to program nearly every possible response. This is often the longest part of robot construction. A little know fact is that the popular electronic hand-held game “20 Questions” is actually a thinking robot. It will evaluate all of your answers and, if programmed correctly, will pick the exact right answer to the item you are thinking about. This is the most basic idea of a thinking robot. Someday, this technology may serve humans by taking on the role of a therapist. Robot technicians call this work “behavioral modification” because robot technicians can actually give a robot its personality, its intelligence, and its ability to relay this information to humans and other robots. Of course, this all can lead into the world of artificial intelligence or “AI“. If you don’t know what “AI” is, think back to your favorite science-fiction movie where robots have their own minds and will to do things on their own. The robot’s intelligence, possibly personality, and its reasoning all contribute to its artificial intelligence.

In America, robots can be used for many different things. In Detroit, there is a very large demand for robotic assembly arms. These go on what is more commonly know as an assembly line. They are also heavily used to stamp molds on nearly every shaped metal and plastic good. Robotics in America have allowed us to look towards the future and influenced a way of life. Even now children are able to play with their remote controlled “robots” or rather, toys that are expensive and interactive. This sudden leap from robotics to toys is making us reevaluate how close to the sci-fi robots we really are. After all, if children are already using them for recreational use, then why can’t adults develop one that is way more advanced?

Of course, there are skeptics that believe that robots take the jobs of human workers. In my opinion, however, robots create more jobs than they take away. Robots need maintaining, installing, construction, and programming. Companies need to be taught how robots function and how they can help their businesses grow. In Japan, there are 500 robots for every 100,00 workers. If America wants to stay industrially competitive, we must continue striving to incorporate robots in our daily lives.

Robot technicians are on their way to developing robots that can do many things that humans can do. Already we have robots that think, process, reply, move, and even have a certain personality. The robot technician’s job is an important and interesting job that may one day even help society function perfectly. But we still are waiting to have R2D2 show up in our living room, and in the meantime we can all imagine in wonder about the amazing possibilities of robotics.

It also is a hobby for card stacking enthusiasts. One definition of card stacking is creating a structure on a very weak and vulnerable base that can literally collapse at any moment.

A simple playing card is not strong at all by any means. Outside of playing a friendly card game, we don’t think of a card as having much capacity to create an engineering feat.

When a card stacker builds a structure, no glue, adhesive or bonding material is used. The cards support each other. Row by row each card contributes to the delicate balance of the whole.

If one card is weak, bent or not placed properly, the entire piece can easily collapse.

Professional card stacker, Brian Berg is the current world record holder for building the tallest house of cards at over 25 feet!

This structure is made from 91,800 cards:

Other card structures on display at state fairs:

How does he do it?

Brian uses Pla-More cards as they have less of a glossy topcoat and lend themselves to easier building. Brian has broken at least seven world records in card building. But is it really about Brian’s special low wax cards? Brian is clearly a scientist as well as an observer of nature.

There are many things in nature that seem to be so weak and yet are so strong. Mother Nature uses the hexagon shape to build some amazingly strong things such as the honeycomb of a beehive, a water crystal and a snowflake.

Structure of a Water Crystal

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The Scutes of a Turtle’s Shell

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A Honeycomb in a Beehive

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A Very Close Snowflake

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Naturally Formed Basalt Columns

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Saturn’s North Pole

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Hexagons in nature fit together without any gaps to make a strong foundation. Hexagons in nature “tessellate” meaning that they repeat themselves over and over using only the same shape as the pieces fit together without any gaps and thus are very strong. Triangles, squares and rectangles also can tessellate the same shape repeatedly without any spaces in between.

In this same way, a card stacker will place the cards in such a way as to not have any gaps in the structure. One gap in the structure will severely weaken the strength of the whole structure. What would happen if the snowflake had a weak link? The entire snowflake could not sustain the weight and collapse, just like a house of cards.

Nature is very efficient and so is a professional card stacker. The total weight of the cards only adds to the overall strength of the structure. The more cards that are successfully stacked, the stronger the actual structure will be.

The successful card stacker uses tessellation in his building of the cards as well. The card stacker will arrange his cards in grids, thus they cannot bend or weaken.

A Grid of Cards as Tessellating Squares

Nature uses this system as well in the construction of honeycomb in beehives. snowflakes, turtle shells and water crystals. Tessellation of the same shape makes the whole structure stronger.

So check out these YouTube links of more incredible card structures and see if you can find the simple principles of nature, in a most complicated human creation. You just might find a whole new meaning for the expression, “house of cards!”

Brian Berg builds the Capitol Building in Washington D.C. out of cards. It took three days for Brian to build this! He is a Harvard grad and has a Master’s in architecture. This is amazing!

This link shows the “demolition” of a creation.