Showing posts with label Engineering. Show all posts
Showing posts with label Engineering. Show all posts

22 December 2010

Giant Sinkhole is not Technically a Sinkhole

In case you missed it earlier this year (end of May), here is some info and pictures from the sinkhole that appeared in the middle of a Guatemala intersection. The views of the thing are really amazing.
May 29, 2010 Guatemala City Sinkhole (Business Insider)
The hole was 100 ft in diameter, and 300 ft deep. You can see from the pictures that looking into it is like staring into the abyss. Somewhere down there is a clothing factory which used to be on the corner of the intersection. So how did this thing happen?

On May 29th of this year, the remains of tropical storm Agatha caused record rainfalls of over 14 inches in Guatemala City, backing up sewer systems. The hole was probably caused by a sewer line that backed up and started to leak, and ash from recent volcanic eruptions may have helped clog the pipse. But a leaky sewer won't make a hole like this just anywhere. Guatemala City is built in a steep valley, with bedrock forming a deep-V.  The bottom of the V is filled in with hundreds of feet of pumice-fill, which is loose gravel like rock from volcanic eruptions. Most of the city is built on the pumice-fill, which is easily eroded and can wash out down to the bedrock, up to 600 feet below. In fact, this is not the first time this has happened.

While amazing, neither of these holes are technically sinkholes. Sinkholes are formed from natural water erosion of bedrock (limestone or sandstone usually). The Guatemala "Holes" are not formed by natural water erosion, nor are they formed in bedrock. Unfortunately, geologists couldn't come up with a better term than "piping feature", so sinkhole is probably going to stick.

01 November 2010

How 3-D TV Works

You have probably looked at 3-D images before with those goofy red and blue glasses. You may have even watched something in 3-D before. Maybe in a movie theater, maybe a TV broadcast from past years. I have done all of these things, but I still thought of 3-D movies or TV shows as a clunky gimmick. So it's a surprise to me as I keep seeing news stories about 3-D TV's. I wanted to know why, all of a sudden, everything needs to be watched in 3-D. As I figured, it comes down to technology.

How This Stuff Works

3DTV's - Not really like this. (MarkWallace)
Most 3-D technologies work by giving the viewer a different image for each eye. Differences in the images give an illusion of depth and make objects appear to be popping out from the screen. 3-D content is easy to produce, just by recording the same thing with two camera lenses in slightly different positions. It is easy enough to be used for many sporting events now. The trick is getting separate images from the screen to each eye of the viewer.

The old red and blue glasses did this by tinting the two images, so the eye with the blue lens could not see the blue parts of the image, and vise-verse. But this messes with the colors and everything ends up seeming blurry, so it didn't catch on. Polarization is another method, used today in movie theaters. Read more here about light polarization. Put simply, two different projectors show images with different types of light, and filters on your glasses block one type of light for each eye. This method requires special coatings on the screen and technology to project two images at the same time, but general consensus is that polarization is the current technology with the best viewing experience.

A Collection of Technologies

The method used in the new home 3-D TV sets is neither of these, and unlike the previous methods, does not

08 October 2010

Issues: Coal Reserves

I am interested in looking at the future of energy. From an engineering perspective, providing electricity and the power for transportation is one of the great accomplishments in history. But it's clear that 100 years from now, it won't be done the way it is today. So I am curious about how it will be done, particularly for transportation. First I wanted to see where we are with the current methods, like fossil fuels. Coal provides about half of the electricity for the US and for the world, so let's see how much coal we have left. Sorry if this is a little long, but there was plenty of interesting information. Also, I am just trying to answer the question of how long would coal last if we kept using it, I am not trying to get into any discussions about political or environmental impact. At least not yet.

There is more energy available in coal reserves than in oil or natural gas. Coal reserves are also more widely distributed between countries of the world than other fossil fuels. Getting a handle on how much coal is left for the world to use is not simple. The most widely agreed upon number is around 900 billion tons, from the U.S. Energy Information Administration, the World Energy Council, and BP's annual report on energy assets. This number is the amount of "Proven" reserves, which is not the total amount of coal in the ground, but the amount that makes economic sense to dig up under current conditions.

Where is the Coal?  (Gunnmap)
In reality there are vast amounts of coal (and oil and natural gas) that we will never use. The EIA estimates that in the United States alone, there are between 2 and 4 trillion tons of coal in the ground, but only about 500 Billion tons are technologically feasible to mine, and only half of that is economically feasible. These reserves change over time – up from new discoveries of reserves, better technology to put more reserves in play, and the addition of more economically feasible reserves as coal prices increase. The 900 billion tons has been steady for a while, but it is more likely an overestimate than an underestimate, because reserve numbers are not updated very well. China, for example, is still using reserve numbers from 1992, despite having mined about 20% of that amount since then. In all of our time so far, humans have burned about one quarter of the coal that would make up our reserves today. Europe is down to less than half of what it started with. But given a need for coal and no cost-effective alternative (a poor assumption), it is reasonable that we could mine twice the amount we current consider reserves.

None of that answered the question of how long the questionable amount of coal reserves will last. If we assume those 900 Billion tons are all we can mine, then it will last about 120 years at current production. But worldwide coal production and usage has been climbing rapidly, at a little over 5% per year for about the last ten. If that continues, then the world will run out in 40 years.

That scenario is unlikely, even without a push towards renewable electricity. The growth will start to plateau at some point. But some growth will happen, and 120 years is very optimistic, even figuring we double the potential reserves with new finds. Any estimates that claim 250 years of coal reserves are either overly-optimistic, or are considering only the United States.

The United States not only has the largest coal reserves in the world (Russia is second), but is mining relatively slowly (though is still the #2 producer). At current rates, the US has a little over 200 years before current reserves are exhausted. Compare that to China, which has the third largest reserves, but is mining almost three times more than the US, meaning that they have only 41 years at current rates. The EU has 51 years. As other countries begin to run out, production in the US might pick up for exports, so it makes sense to analyze this globally.

All of this might be a needless way looking at coal production, because economic factors might be too important for the world to ever end up completely running out of coal. There is the idea of production peaks (see peak oil) for finite resources, where, well before a resource runs out, it climbs to a maximum production, then falls over time until the resource is depleted. Now, the reasons for this are both physical and economic, and honestly beyond me. A peak in coal production may happen well before 2050, followed by anything from a global crisis - if the need for coal stays but supply drops - to no problems - if the world smoothly switches to other forms of energy as production declines. A common estimate for this coal peak is 2025, but predictions vary wildly, and peaks are difficult to predict (I.E. the oil peak may have already happened, but we won't know for sure until we see a few more years of data).

So, regardless of any peak, somewhere between 60 and 80 years of coal is likely available if a major shift is not made in coal usage. But a major shift is what I am concerned about. Oil and natural gas reserves will run out well before coal, so an option to keep in mind, along with other alternatives, is to use coal to replace other fossil fuels, with coal-to-methanol or coal gasification. I might write about them later, but it appears that the numbers don't support these methods. Replacing oil with coal will reduce the reserves of coal faster and still put the year of depletion around the same time for either scenario. It may be worthwhile to discuss these processes from a standpoint of energy independence, so the US could cut down on oil imports, and again, I am ignoring (for now) everything about CO2 emissions. I'll get to some of those topics in another post.

13 September 2010

A Photograph of Philosophical Importance


Take a look at this photograph.




At first it might appear slightly interesting, a black and white photo, clearly from many decades ago. But this photograph is special because of its timing. This was taken way back in 1838, by Louis Daguerre as he was experimenting with the process to record images. It is of the Boulevard du Temple in Paris, and is one of the first photographs ever taken. Now the streets of Paris were not as empty as they appear here. Early photographs had to be exposed for several minutes (over ten for this one) to collect enough light, so anything that is not completely still for that time becomes a blur, and anything moving faster than a snail is invisible. Notice how blurry the trees are compared to buildings or streetlamps. This street was probably busy, but the moving people and carriages blended into the background. Except in the lower left. Let me zoom in. 

 


A shoeshine and his customer were still enough to be captured in this photograph. That makes this the earliest photograph of a person. Let me repeat that: Above is the very first photograph of a human being. Just something to think about.


 

06 September 2010

Update: Micro-pumps for micro-needle patches!

Patch Pump for Vaccine Delivery (Purdue University)
Remember a few weeks ago, I linked to an article about micro-needle patches? They were an ingenious new way to deliver vaccines easily (and painlessly). However, this new article mentions a problem not stated in the previous one; Large molecules of many drugs do not readily dissolve out of the needles and into the skin. For that, they needed a pump of some sort to drive the medicine into the skin. Scientists at Purdue University have done just that! The mechanism seems complicated (and slightly worrisome if something were to break in the pump), but it's still in the testing phase, so lets just get excited about it!

New pump created for microneedle drug-delivery patch.

13 August 2010

Links: Disappearing Amphibians, Rabid Vampire Bats, and Plans for Cleaner Energy

Amphibians have been declining world-wide over the last several decades due to a mixed cocktail of pollution, habitat loss, climate change, and the uncontrolled spread of a devastating infectious fungus. One such amphibian is the elusive Golden Toad, which has not been seen since 1989. Now, scientists have begun a world-wide search for 100 of these frogs that have disappeared, hoping to find residual populations that can be protected.

Global hunt for "extinct" species of frogs.


Peru is battling a vampiric horror! Mainly vampire bats, bats that bite and drink the blood of sleeping mammals, that are infected with a strain of rabies. Four children have died after being infected by these animals, and over 500 people in total have been vaccinated after being bitten.

Peru battles rabid vampire bats after 500 people bitten.


And this week is big news for alternative energy... or at least plans for the next 20-or-so years. Research in nuclear power puts plants around the world by 2030 and a recycling idea that would negate the need for dealing with radioactive wastes! On the other spectrum, research into biodiesels that are made from plant-grown micro-algae claims to be able to produce sustainable and cleaner energy in 10 to 15 years, eventually eliminating the need for fossil fuels! Whether we can afford it is another aspect all together.

Scientists outline a 20-year master plan for the global renaissance of nuclear energy

Industrial production of biodiesel feasible within 15 years, researchers predict.

07 August 2010

Links: Crazy Bus, Regeneration, and the Beauty of Alaska


Engineers in China have come up with a pretty elegant solution to the problem of overcrowded streets and buses stuck in traffic. They put the bus on stilts and it just drives over the other traffic while only taking up a tiny strip of road on either side.

China Hush: Straddling Bus


Possibly the holy grail of medical technology is human regeneration. It's the idea that we might coax the human body into growing back a lost limb or heart tissues that has led to all kinds of research. Healing cuts in your skin and broken bones are minor forms of regeneration that happen naturally, but, unlike simpler animals like amphibians, we can't regenerate larger parts of our body, probably because evolution forced us to trade long life and cancer resistance for wildly growing cells that can rebuild parts from nothing. This week plenty of news came out related to regeneration research. Here are a few stories. We are still a long way from regenerating a lost limb, but scientists are working on it.

NY Times: Two New Paths to the Dream – Regeneration

BBC News: Surgeons Rebuild Windpipe with Stem Cells

Nature: Skin Cells Converted to Heart Cells (more technical)


Jim Harris Photography
Last today, an incredible photo-essay of a backpacking trip through Alaskan mountains and glaciers. If you are one for beautiful nature pictures, you probably won't be able to stop scrolling down the page. The picture on the right is just one of many.

33 Days Across Wrangell-St. Elias NP, Alaska: The Southern Spiral


Also, this.

04 August 2010

Links: Composting Plastics, Venomous Octopuses, and Serenading Sharks.

Here's another link post, so you don't have to read my silly writings!


Our first link is about biodegradable plastics, the development of which has been going on for several years and there have been some results. These "plastics" are actually made from plant material, such as corn starch or tree-produced sugars, and degrade in a compost environment in 6 months time. I wonder when we'll be seeing these plastics in our grocer.

Compostable Plastics have a Sweet Ending @ ScienceDaily.com


World Centric: Bioplastics, a producer of these decomposable plastics. 
Great White Shark


Second is a quite silly continuation of our Ode to Discovery's Shark Week, a man serenading Great White Sharks. He was actually in the water with the sharks and guitar, but I'm guessing they dubbed over the music :).

Seriously, the video's pretty funny.


And our final link also takes place in the ocean, but deals with something with a little less of a backbone. It wasn't until recently that scientists discovered that all octopi, not just the Blue-ringed Octopus, are actually venomous. A study into Antarctic octopi discovered four new species of octopus and two completely new toxins that these octopus carry.

Scientists Tap Into Antarctic Octopus Venom

27 July 2010

Deer Cross Here

Why did the chicken cross the road?

One of the largest problems with wildlife habitat is the problem of fragmentation. This is where a block of forest or plains or marsh is split into smaller pieces. This fragmentation can be caused by farmland, housing, or forestry, but most often occurs due to roads and is even a large problem in natural reserves. Roads represent an extremely dangerous crossing for most wildlife, as well as drivers, primarily due to collisions with vehicles. They also cause problems by splitting up wildlife populations (small groups of animals are more vulnerable to being wiped out than large groups), degrading habitat close to roads due to maintenance and pollution, and preventing access to resources on the other side.




Because there wasn't a bridge!

(Joel Sartore)
This problem has been tackled a few different ways. Underpasses that allow wildlife to cross beneath roads have been created for creatures who don't mind dusty, dark, enclosed spaces, such as turtles and raccoons. Large enough underpasses have even been used by deer and moose! However, large carnivores such as wolves, cougars, and bears generally don't like them. So if you can't go under, let's go over! Many wildlife-conscious areas, such as Banff National Park in Alberta, have begun installing wildlife crossing bridges or "green bridges" as they are often called. First installed in France in the 1950's, these are usually wide bridges planted with grasses and small shrubs with fences along the edges.


Success?

Green bridges have been shown to help lessen the effects of fragmentation and to decrease the number of vehicle collisions with large mammals by an average of 86% close to where the bridge is in place (sec. 4.4). They are currently being used in many areas with a high rate of success. In Florida, several underpasses have distinctly lowered the casualties of florida panthers on highways where they have been installed. Not just for roads, overpasses over a deep irrigation canal in Arizona have decreased the number of deer and other animals from getting stuck and drowning in the canal. Researchers have picked out tons of road kill "hot spots" that could benefit from crossings, but it's still a matter of time and money until they're considered everywhere.

26 July 2010

Moscow, the New Skyscraper Capital of Europe


Moscow's newly built skyscraper garden (Img:Bradmoscu)
Completed in 2010, the taller of the two City of Capitals skyscrapers, located in Moscow, is the new tallest building in Europe. Moscow is also home of the second and third tallest buildings in Europe, all completed in the last decade. Maybe the Russians feel that ground level is not cold enough in the Moscow winter and would rather be 1000 feet in the air. At 306 meters tall, about the height of US Bank tower, the tallest building in Los Angeles (the Sears Tower Willis Tower is 442 meters; damn it, I just can't get used to that.), City of Capitals is located in Moscow's International Business Center district. The same district contains four of the five tallest buildings under construction in Europe, all of which will be taller than City of Capitals, though at least two are on hold due to the economic downturn, and an additional, even taller, project has been canceled outright. The other of the five tallest buildings under construction in Europe is in London.