Art from Tor.com.

Vilcabamba is another free story by Harry Turtledove that I ran across over at Tor.com. The story is told through the point of view of Harris Moffatt III, president of the United States and Prime Minister of Canada just like his daddy and granddaddy before him. Turns out, during Harris Moffat the first’s tenure as president the Earth was invaded by aliens and Harris is in charge of the only part of North America the aliens didn’t find useful. And even that is about to change now that the aliens found a silver deposit in Utah.

Spoilers ahead, go read the story first if you don’t want to hear the rest.

The whole story is a brazen reference to the European colonization of North America with the entire human race in the role of Native Americans. Humans met the aliens peacefully when they landed, but the Krolp came out shooting. The Krolp take most of the land but leave the natives the land that’s least useful and hardest to live on, and then decide they want that too when precious metals are discovered there. The aliens are centauroid with four legs and an upright torso just like the Europeans appeared to the Native Americans when they were riding horses. Even the title is a reference to the subjugation of Native Americans. Vilcambaba was the last hold-out of the Incan empire and was abandoned in 1572 when the Spaniards sacked the city and relocated all the inhabitants to a new city. Just about the only thing that happens differently is that humans didn’t have to help the invaders survive for the first few years.

The story ends with the Krolp conquering the rest of the US and leaving no free humans except those hiding out in remote places. It was a fine story, but aimless and not especially entertaining. It was a lot like reading about a rock slowly rolling down a hill toward a defenseless baby. You know what’s going to happen and there was really no point.

I would have much preferred a slightly different story. Turtledove briefly mentions humans who attend the Krolp school and how they are being assimilated. To me the aftermath of the Krolp’s final conquest would have been a much more interesting story. I would have enjoyed reading about how human culture was slowly assimilated into Krolp culture. Perhaps a story two hundred years in the future when a few humans are running casino for the Krolp.

Like the last Turtledove story I reviewed, this one is much more interesting for the questions it raises about the future rather than the story itself. It’s not a great story, but short enough to still be worth a read just because it makes you think You can get it free at Tor.com or buy it for the ereader of your choice.

I don’t remember what I thought when it was originally released in 1999, but these days it strikes me as a childish movie.  Jar-jar’s antics had the kids in the theater rolling in the aisles.  The humor was so over blown and obvious it almost seems like a movie written for kids.  I think it’s safe to say that wasn’t intentional given the franchise as a whole.  Star Wars isn’t exactly intellectual, but it was never aimed strictly at kids.  More likely it’s an example of Lucas wanting to make sure everyone knew he was trying to be funny.  Mostly, the comic relief overshadows everything else that goes on.

I do vaguely remember little Jake Lloyd getting savage reviews for his portrayal of nine year old Darth Vader.  I  wouldn’t call it a great performance, but I mostly wrote that off to an inexperienced child actor and an inexperienced director.  (I’m not sure Lucas qualifies as an inexperienced director, but he certainly seems to make the mistakes you would expect from one.)  Lloyd’s line readings are more like line readings than dialogue, but he comes off with a fair amount of charm that was severely lacking when Hayden Christianson took over the part.  (On my charitable days I’m willing to assume that’s the way Christianson chose to play the role of the galaxy’s second greatest villain.)  Lloyd does hint at a dark side that we all know will win out in the end.

I was interested in seeing the 3D, but my main reason for going was just to get the theater experience again.  It’s fortunate that was my mindset because the 3D was almost non-existent.  I may have been spoiled by all the movies coming out lately that were specifically made for 3D, but I got very little out of the 3D conversion here.  It did add a little excitement to the action scenes like the pod race and the three way light saber melee at the end, but mostly it just seemed to add a little depth to the scenes when the actors were standing around talking.  I didn’t see much point to the conversion.  On the plus side, it didn’t have the ghost images that some recent 3D conversions have been getting complaints about.

I don’t feel like I can provide a good see/don’t see recommendation on this one.  If you hated the original release, or if you’ve seen it countless times on the small screen, I’m going to advise you to stay home.  If you’re a fan of the movie, or a franchise fan who hasn’t seen this installment in a long time, then you’ll probably have an enjoyable two hours.  If you do go, try to be impartial because it really is a better movie now that it has 13 years and two sequels under its belt.    My enthusiasm for seeing the original trilogy in 3D is a bit dimmer than it was a week ago, but I still look forward to seeing the Death Star trench run and the battle with the walkers on Hoth when those conversions come along over the next few years.

My biggest regret is that my kids aren’t yet old enough to tag along.  Phantom Menace is the most kid friendly of the series, but I can’t quite bring myself to take a couple of four year olds in.  On the plus side, by the time the3D versions of the original trilogy come out they’ll be slightly older than I was for the originals, so they’ll be able to experience them the same way I did without the prequels muddying the water.  Being able to experience it with my kids is the real plus of the rerelease.

Did you notice how I very carefully didn’t mention how Darth Maul, a potentially great villain, is killed off after only a few minutes of screen time? An enormous waste….

Horseshoe Falls as seen from Niagra Falls, Ontario

When I say flow, what I really mean is ‘volumetric flow rate’.  In layman’s terms, flow is the volume of water that passes a certain point in a set period of time and it’s generally expressed as either gallons per minute (gpm) or cubic feet per second (cfs).  The equation for flow is:

Q = V * A

Where Q is flow, V is velocity of the flow, and A is the area of the flow.

For instance, say you have a square ditch running by your house.  You know it is three feet wide and five feet deep, but the water in it is currently three feet deep.  That makes your area 3 ft * 3ft = 9 square feet.  You measure the velocity of the water and determine it’s moving about 2 ft per second.  That means the flow rate in that ditch is: Q = 2 * 9 = 18 cubic feet per second.

The numbers themselves aren’t that important.  The most important thing to take away from this discussion is how the variables affect each other.  If Q goes up, V or A must go up.  If A goes down then V goes up, and so on.

Let’s continue our example above.  The neighbor wants to slope his yard so it also drains into our ditch.  His yard is about the same size as ours, so we’ll assume he’s going to have about the same amount of water.  Suddenly the Q in our ditch doubles from 18 to 36.  Do we let him do it?

If our Q is going up, then V and/or A are also going to have to go up.  Velocity depends on what the ditch is made out of and how steep it is, and the neighbor isn’t going to change those so we’ll assume our velocity stays the same as before, but the ditch is 5 ft high and our water is only 3 ft deep so area can increase when the flow does.  But is it enough?  To figure that out we’ll calculate the maximum flow the ditch can hold.  We do that by using the entire ditch height rather than just the 3 ft of depth.

A= width * height = 3 ft * 5 ft = 15

Q = 15 ft * 2 ft/sec = 30

So our ditch will hold 30 cubic feet per second without overflowing.  We calculated the flow in our yard to be 18 cfs and we think the neighbors will be about the same.  So if we let the neighbor do what he wants there will be 18 + 18 = 36 cfs of water in our ditch.  But the max is only 30 cfs.  So we tell the neighbor no, because it will make our ditch overflow.

Another way to use our new found knowledge…. Maybe you decide to put in a flower bed next to the creek and want to make it more narrow.  You can can do the same calculations with a smaller area and see how that works out.  Or if you’re afraid your kids are going to fall down the five foot vertical wall and want to make it a shallow slope instead, you can figure out the best way to do that.

I’ve simplified it quite a bit, but now you know the foundation of hydraulic engineering, so we can build on that.  Later I’m going to talk about bridges and levees and how they affect flow.

The tower was built in 1869 on the banks of Lake Michigan. A pumping station is built into the base, and the 154 ft tall tower provides supplemental pressure. It’s one of the few buildings that was still standing after the famous Chicago fire in 1871. It’s no longer used as a functioning water tower, but the area where it stands has become known as the water tower district and one of Chicago’s many skyscrapers is named after it. It was reportedly described by Oscar Wilde as “a monstrosity with pepper boxes stuck all over it”. If Wikipedia is to be believed, the castle design
inspired the White Castle logo. I had trouble finding good pictures because most were copyrighted and not available for reposting.

You can see the tower here on the left with another famous Chicago tower behind it.

The tower also inspired this painting by Thomas Kinkade.

Eiffel Bridge between Mordova and Romania. Designed by Gustav Eiffel (of Eiffel Tower fame) in 1877. Still standing.

The Eiffel bridge today.

Historically speaking, all engineering was civil engineering.  Engineering was practical and based on trial and error, and seeing what worked for others.  Publicly acclaimed engineers were known for great bridges, cathedrals, or military works like castles.  The term ‘civil’ was added to distinguish between civilian and military engineering.  The other commonly acknowledged types of engineering came along as human knowledge expanded and other specialties were necessary.  For instance, mechanical engineering was unknown until the Industrial Revolution brought the wide spread use of machinery.

The chief contribution of civil engineers to the world can be summed up in one word.  Infrastructure.

Qanat cross-section from Wikipedia

I’m certainly biased, but I tend to think of infrastructure as the underpinnings of the civilized world.  Water supply, roads, bridges, all the utilities you take for granted…. they’re all infrastructure and they’re all key to any large scale human endeavor.  You can live without it, but if you want to live well you need infrastructure.

 A good infrastructure has been key to the success of many of the most powerful empires through history.  The Persian system of qanats made it possible to farm semi-arid areas providing food for a big population and freeing up men to be soldiers to extend the power of the Persian Empire.  Rome used its unprecedented road system to tie its far flung empire together and transport the legions which projected its power.  The American interstate system gives fast access to the resources of its vast interior lands and speeds the food grown in the Midwest to the coasts making it possible to have cities like New York and Los Angeles.

Modern day engineers are responsible for making sure your life goes as smoothly as possible.  Everything from making sure you have enough water pressure to take a shower, to designing the bridges you drive across to get to work, to making sure the airport runway is long enough for your plane to get in the air, to making sure the new Target being built down the street has enough parking and doesn’t flood your house when it rains.

Quite a few sub-specialties fall under the civil engineering branch, and I’m probably going to talk about a few of them over upcoming months.  In the mean time, I suggest you find a civil engineer and give him a kiss (or handshake if that’s more your thing).

Artwork from the publisher, TOR.

I’ve been discovering lately that telling stories shorter than novel length preserves what I enjoy about my favorite authors while often keeping them from indulging themselves in some of the habits I like less. To be more specific, when I read Harry Turtledove’s alternate history story, Lee at the Alamo, I found it engaging without using Turtledove’s common device of rotating point of view characters and time jumps of indeterminate length between chapters. The story did have a stilted and overly formal feel to it, but that did conform to my pre-conceptions about how things were done in the 19^th century.

If you’re not familiar with the conceit, alternate history is a genre with its roots in real history. The author looks at a historical occurrence and speculates on what might have happened if it had occurred differently. It’s a genre I find speaks to my own need to consider all sides of a decision (which generally leads to indecision). I also feel like it teaches a little history, encourages critical thinking regarding consequences to your actions, and points out how so many seemingly disparate things are linked.

The historical event Turtledove chooses to ‘what if’ in this story dates back to the beginning of the civil war. Texas has just seceded from the union due to Abraham Lincoln’s election as president and is in the process of taking over the U.S. Army’s supply depot at the Alamo and sending all U.S. Army troops, including Lt. Colonel Robert E. Lee, back to Washington. In our history Lee’s commanding officer, General Twiggs, capitulated to the Texans right away and was appointed a general in the Confederate Army.

In Turtledove’s version Twigg was delayed by illness and unable to take command in Texas leaving Lee in command. Lee decides to resist the Texans demands and makes a stand in the Alamo with all his troops who are loyal to the U.S. The Texans lay siege to the Alamo and antics ensue.

I enjoyed reading the story, but not so much for the work itself. The questions raised by the ending were the most interesting part of the work. In our history Lee did not want to join the confederates, but decided to do so because his Army superiors wouldn’t let him remain neutral. (Spoilers ahead, skip to the last paragraph if you don’t want to read them.) In the story Lee is eventually forced to surrender to the Texans, but his resistance provides the first Union victory in the Civil War and makes Lee a hero in the north. In light of his hero status, President Lincoln allows Lee to sit out the war without fighting on either side.

Lee’s leadership is responsible for many of the Confederate State’s biggest victories so removing him from the war could have a lot of far reaching implications. The war might be much shorter resulting in less loss of life and destruction throughout the south, which could in turn mean less resentment from southerners and a much shortened reconstruction period. I’m no historian, but I think a case could be made that the civil rights era might have been much less tumultuous if southerners hadn’t still been nursing so much resentment toward northerners and blacks for the perceived slights of the Civil War and Reconstruction.

So there you have it. While it was a little rough around the edges, it was an interesting story and I did learn a few new things about Lee as a historical figure, and about the Alamo. I found Lee at the Alamo to be an interesting story for the questions it raises and I’d love to hear what someone else thinks. You can get it for your e-reader ($0.99 in the Kindle store) or you can read it for free on the publisher’s web site.

I was looking for a change in the distribution of the failure causes.  As the statistics from the last post point out, the majority of bridge failures are caused by hydraulic issues, but hydraulic factors have always been one of the least understood parts of the bridge design process.  Through the 1980′s it was mostly an approximate process.  That all changed due to two major bridge failures, one in New York state and one in Tennessee.  Lives were lost during both failures, and both drew a lot of attention nationally from the public and from engineers.  As a result, a lot of research has been done on bridge hydraulics and scour and state DOTs developed design standards in these areas.  So I was curious to see if that shifted the failure statistics away from hydraulics.

Nope.  Sure didn’t.  The statistics from the 2006 dataset were surprisingly consistent with the 1991 data.  Hydraulic failures went from 60% to 58% with the 2% drop being offset with a 2% rise in overload failures.  Since the 2006 data was merely an updated version of the 1991 data I decided to separate it into pre 1991 and post 1991 data sets.

So as one final check of the data, I separated the New York state data from the rest of the country.  The assumption being the New York data would be more comprehensive since New York State DOT was collecting the data.  The resulting analysis did show a significant shift.  Hydraulic failures dropped to 48% while collision failures went up to 26%.  I think this is because collision failures happen more often on smaller bridges and aren’t as widely reported in the national media.

I don’t think it’s a good idea to make any grand conclusions due to the nature of the data collection, but I suspect the analysis of the New York state failures shows the distribution between hydraulic and collission failure causes more accurately.  The most surprising part of the analysis was how consistent all the numbers were.  There was very little change from 1991 to 2006, and even breaking out just one state showed almost no change in any of the failure causes other than hydraulic and collision.  (And earthquake failures were not represented in the New York data.

It’s tough to find any statistics on bridge failures.  Surprisingly, there’s no national database on bridge failures.  The best I was able to find is an database that New York State DOT keeps on bridge failures.  It basically includes entries for whatever they have heard about either in the media or what was volunteered by other state DOTs.  It’s nowhere near comprehensive on the national level, but presumably it would be pretty accurate for New York since they would be well informed about their own state.

Before I share the statistics, there are a couple of things to keep in mind:

1. This includes all bridges, not just the big ones that end up in the national media.  Most bridges are small structures  and not of interest to anyone outside the immediate area they are located in.
2. Failure doesn’t necessarily mean going down in a spectacular cloud of dust.  A structure failure is anything that keeps it from being used in the way it was intended.  And now for the statistics…….

The biggest number of failures by far are caused by bridge hydraulics.  This means anything related to water and includes things like bridge scour, being clogged by ice or debris, approach road wash-outs, and just being pushed over by water.  Hydraulics is my specialty area and I’ll cover some of those in more depth in later posts.  The second greatest is collision.  I’m not entirely clear about this label, but I assume it means collisions by boats as well as collisions by trucks.  The overload and earthquake labels seem self-explanatory.  I assume fire refers to wooden bridges, but I do know of at least once instance  where a tanker truck blew up under an interstate bridge and melted the beams so badly the entire structure had to be replaced.  (It does occasionally happen outside of Michael Bey movies.)

I’m going to do a more in-depth analysis of the statistics in my next post so you folks who got your fill here can skip it.

Source: Wikipedia

The image is provided by Digital Globe. (click image for bigger view)

I also found this approximate representation of the ship and sea bottom.

Source: Wikipedia

One of my old college professors once told us a story about the difference between scientists and engineers.  You put them both in a closed room together.  The door isn’t locked, and they can take as many steps as they want.  The catch, each step can only be half the distance to the door.  The scientist would starve to death because he can never get closer than half the distance to the door.  The engineer, on the other hand, takes his ‘half way’ steps until he gets close enough.  Then he says ‘Close enough’, grabs the door know, and goes down the street to get a few beers. 

The story isn’t as funny now as it was back when I was in school.  In the real world (as opposed to a college campus) the line between engineering and science is blurry.  A good practitioner of either has to dabble in the other.  But it does strike at the heart of the difference between a scientist and an engineer.  Science is about exploring the principles that make the universe work, and it helps to be very literal down to the smallest detail.  Engineering is about taking those scientific principles and making them work to our advantage and sometimes requires a hard-nosed practicality to make things work.

In short, engineering is problem solving through applied science.  Engineering is a broad field with lots of branches , and each of those branches even further.  I’m not really qualified to talk about most types of engineering, but I do want to explore my particular branch of the engineering tree in my next post.

For a little more info, see the National Society of Professional Engineers.