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Carrier Pigeon Faster Than Broadband Internet

Posted date: 2:33 PM / comment : 1 , ,

In South Africa, a carrier pigeon carrying a 4GB memory stick proved to be faster than the ADSL service from the country's biggest web firm, Telkom. Winston the pigeon took one hour and eight minutes to carry the data across the 60-mile course, and it took another hour to upload the data. During the same time, the ADSL had sent just 4% of the data.

--> The race was held by an IT company in Durban, South Africa, called Unlimited IT. One of Unlimited IT's employees complained about the slow speed of data transmission on ADSL, saying that data would get transferred faster by carrier pigeon. To highlight just how slow the broadband internet is, the company decided to test that claim.
Kevin Rolfe with Winston
Source

The 11-month-old Winston flew 60 miles from Unlimited IT's call center in Howick to another office in Durban. To make sure that the bird didn't have an unfair advantage, Unlimited IT imposed some rules on its website, including "no cats allowed" and "birdseed must not have any performance-enhancing seeds within." Hundreds of South Africans followed the race on social networking sites Facebook and Twitter.

--> For its part, Telkom said that it was not responsible for Unlimited IT's slow broadband speeds. A Telkom spokesperson said that they had made several recommendations to Unlimited IT to improve its service, but none of the suggestions had been accepted.

As the BBC reports, South Africa is one of the countries that could benefit from three new fiber optic cables being laid around the African continent to improve internet service. -->
For more information about the pigeon race visit the official website.

Sources

BBC NEWS
News24
Reuters
Wikipedia

For Fun





DNA and How to Extract It

Posted date: 6:17 PM / comment : 0 ,

DNA and How to Extract It

This past March, a few days after my birthday, I spent a Saturday teaching three iterations of a three-hour-long class called Hands-on Introduction to DNA! to seventh through ninth graders at Spark, a day-long assortment of classes for middle and high school students organized by the MIT student group ESP (Educational Studies Program) and taught by MIT students and community members. ESP seems to contain most of my Random Hall friends as well as the wonderful Anna H. ’14, who has blogged about teaching ESP classes here and here.
This year’s 266 Spark classes included classes you might expect, such as Computational Language Theory and Extreme Math, and classes you might not expect, such as How to Plan and Execute Covert Operations in Deep Cover and The Game Mechanics of Pokémon. There was Synthetic Biology, Projective Geometry, Chocolate Tasting, and Slide Rules. There was Crayfish: Take It Apart!, Sea Urchin: Take It Apart!, and their antithesis, Put Together the Pile of Junk!
My Spark class revolved around a DNA extraction protocol that my little brother Max tried as a science fair project. We started out with a short introductory lecture about DNA and then we isolated the genetic material from peas, corn, and strawberries, which was an awesome, colorful, goopy mess. If DNA is nothing new, feel free to skip to the video and the extraction protocol, or just the extraction protocol.
From the beginning—
Our bodies are an ecosystem of hundreds of trillions of tiny bacteria and tens of trillions of our own cells, small bags of stuff that do a lot of work to keep us alive. We are interested in the nucleus of the cell, which encloses the DNA.
Your DNA is a story, uniquely yours, that you read out as you live and eventually pass on to your children. Instead of paper, it is written on a long string using only four letters. Each word in the story is three letters long. The words form sentences called genes, which, alone or in groups, determine the traits you start with, for example your hair color, your eye color, and your blood type. Though your cells have diverse specializations, your DNA is identical in every cell of your body. It contains all the information needed to build you up and then maintain you; it determines how you will grow and develop within your environment and to a potentially large extent it dictates how and when you will eventually break apart and die.
A priority in current research is deciphering our DNA and the DNA of other species for use in medicine, agriculture, and history. The hope is that by learning how to read our DNA, we will be able to better understand genetic disordersand detect them before they appear, improve crop yield, and understand how we got to be human. Genomics is a new and quickly evolving field with a huge capacity to extend and improve human life.
For the most part, DNA carries out its action through proteins. A gene is first transcribed into less stable messenger RNA. Interrupting, or intronic, information is cut out of the messenger RNA and the remaining RNA molecule is sent out of the nucleus and into the endoplasmic reticulum. In the endoplasmic reticulum the messenger RNA is copied again, this time into protein. This final translation is done by transfer molecules, which contain the code for translation, and ribosomes, which line up the messenger RNA and the transfer molecules so that they can interact. The transfer molecules, called tRNAs, are like three-pronged forks. On one end are three letters from the original DNA sequence, a word, written in RNA. The other end holds the corresponding protein monomer, the amino acid. The amino acid that corresponds to each word varies depending on the species. The ribosome lines up the transfer molecule forks with the attached protein monomers along the RNA. The amino acids are connected to form a protein, after which the transfer molecules are reused and the messenger RNA is degraded.
The cell sends the completed protein product to the Golgi apparatus, the cell’s post office, and the Golgi packages the protein and sends it to its destination inside or outside the cell. The protein then carries out the function prescribed by its encoding DNA, whether it is the keratin in your hair or an antibody in your immune system. Meanwhile the original DNA is safe in the nucleus, in two copies. It never leaves, and it is split apart and replicated only when the entire cell is replicated.
The human genome is written in about 3 billion base pairs, or letters. If you stretch out the DNA from one nonreplicating cell, it will be about two meters long (3 billion base pairs in 23 chromosomes ∙ two of each chromosome in the cell ∙ 0.34 nanometers between consecutive base pairs). If you concatenate the DNA from all of your cells and stretch it out as one string, it will reach the sun and back 67 to 333 times, or the moon and back 25,000 to 125,000 times (2 meters of DNA in each cell ∙ about 10 to 50 trillion cells in the human body ÷ 300 million kilometers from the Earth to the sun and back, or 800,000 kilometers from the Earth to the moon and back). In the cell, the DNA is wound tightly around proteins called histones, and for this reason, even though we will try to degrade the proteins, the DNA will precipitate in clumps rather than clean strings when we extract it from a vegetable or fruit.
Here’s all that in vivid, computer animated action:
This video is from the Walter and Eliza Hall Institute of Medical Research in Australia. They have other equally mesmerizing and informative animations in high definition on their web site, and you should go watch them, too, if you enjoyed this one.
While we watched this video we set up the first steps of the DNA extraction protocol, which contains a convenient 10-minute break. Below is the protocol we used. The students wanted to know what each step does to the DNA, so I’ll try to explain it here as well.

Materials:

  • A blender.
  • A mesh strainer with very small holes.
If you are alone:
  • A clear cup. It looks really cool if you use a champagne glass.
  • A wooden BBQ skewer or something else with which to stir.
  • One eighth teaspoon table salt.
  • About one cup of cold water.

     
  • A pinch of meat tenderizer or contact lens solution. (We used meat tenderizer.)
     
  • Two tablespoons liquid laundry detergent. Use clear laundry detergent. Colored laundry detergent will overpower the color of the fruit or vegetable.
  • About half a cup of something that was once alive. It’s okay if it’s frozen. We tried strawberries, split peas, and corn. The kids were most excited about the strawberries. I thought the peas looked coolest. The frozen corn was not very exciting for anybody.
  • A small jug of rubbing alcohol with at least 95% alcohol content.



If you are with 10-20 friends:
  • A bag of small, clear, disposable cups. The more translucent cups are worth the extra money.
  • A bag of wooden BBQ skewers or something else with which to stir.
  • One container of table salt from your kitchen.
  • Gallon jug of cold water, which you brought to school empty and filled with cold tap water in the bathroom before class.
  • Two small shakers of meat tenderizer. You won’t use much of this, but it’s better to have two so that they can both be passed around at the same time.
  • A small bottle of clear liquid laundry detergent.

     
  • A bag or two or three of something that was once alive, like a fruit or a vegetable. It’s okay if it’s frozen.


     
  • Several jugs of rubbing alcohol with about 95% alcohol content. You’ll need about as much rubbing alcohol as vegetable or fruit, which might be a lot. (Weird looks at the check-out line come with the vast, yellow and green polka-dotted territory of being awesome.) Leave time to potentially stop by multiple CVSes.
Among the materials, rubbing alcohol (isopropyl alcohol) can cause irritation to eyes, skin, or the respiratory system. Isopropyl alcohol vapors can irritate the eyes and the respiratory system, contact with eyes can cause damage and burns, and ingestion or inhalation can cause vomiting, drowsiness, and death. The lethal dose is about one cup. It’s unlikely you’ll be able to drink very much, but if you do you will die. You also don’t want to eat the laundry detergent or get it in your eyes.

Procedure:

  1. Combine in the blender one part vegetable or fruit, two parts cold water, and the salt. If you’re doing this alone, it’ll be half a cup of vegetable or fruit, one cup water, and one eighth teaspoon salt. If you’re doing this with a group you’ll want to fill the blender and scale up the salt appropriately. Blend on high for 15 to 25 seconds. It is not important that the water be cold, but it is helpful. Most things, including DNA, tend to be less soluble at lower temperatures. (The exception is proteins, which start denaturing, or losing their structure, at higher temperatures, exposing their hydrophobic parts and forcing them to clump together to avoid surrounding water.) The salt, NaCl, dissolves in the water, separating into the charged ions Na+ and Cl-. The Na+ neutralizes the negatively charged DNA, allowing the DNA strands to clump together rather than be repelled by each other’s negative charge.
  2. Balance your mesh strainer over a clear cup and pour the liquid contents of the blender through the strainer and into the cup. The cup should be at most half full. If you’re doing this with a group you should divide the contents of the blender equally among the group and line the cups up on the table for the next step. Keep in mind that the goop that comes out of the blender earlier has more DNA in it than the goop that comes out of the blender later.
  3. Add two tablespoons of clear liquid laundry detergent to each cup of vegetable goop. If you’re doing this with a group you can use the bottommost line in one of the plastic cups to measure out a very approximate two tablespoons. The laundry detergent disrupts the membrane enclosing the cell and potentially the nuclear membrane enclosing the DNA.
  4. Distribute a vegetable goop cup and a BBQ skewer to each person. Everyone should stir gently and then let the solution stand for 10 minutes. Now is a good time to watch the above 7-minute video.
  5. Pass around the meat tenderizer and the rubbing alcohol. Each person should add a pinch of meat tenderizer to their cup and stir gently again, and then add about as much rubbing alcohol as there is vegetable mixture. The rubbing alcohol makes the DNA clump together, since the DNA is less soluble in rubbing alcohol (or any other alcohol) than in water. The meat tenderizer contains protease, an enzyme that degrades the proteins that accompany the DNA.
The DNA will appear as white goop on the surface of the green or red goop. You can spin it onto the BBQ skewer like cotton candy, but I think it looks prettier and much less gross if it’s left in the cup. Here are some photos my students took at the end of the process. The fruits and vegetables used, clockwise from the top left, are strawberries, peas, corn, and mixed berry, all frozen. That no one photographed the DNA extracted from the corn is, I think, additional testament to frozen corn not being very interesting.
 

 
  

Afterwards, I opened the floor to questions and short chalk talks and we ended up going in very interesting directions. I almost wish I’d had an older class so that students could teach each other more than I talked at them, but at the same time it seems like younger people ask more questions and their questions are often more interesting. Some of the things we talked about were transposons, viruses, cancer, stem cells, ribosomes and the RNA world, DNA sequencing technologies, sex chromosomes and their evolution, alternative splice sites, and the evolutionary benefits of aging and death.
I got some emails in the following days expressing interest in biology and asking about things we talked about in class, which was such a wonderful feeling. If you have time and a presentation at your local elementary school seems like something you would enjoy, you should ask about trying it. A few weeks ago my mom repeated the presentation and the DNA extraction with my little brother’s fifth grade class, and apparently they asked even more interesting questions. It seems like elementary school teachers are usually thrilled to have alumni or parents present about what they've been up to in high school and college and beyond.
If you are in middle or high school and you'd like to learn more about genomics and DNA, there are free resources online that you should check out:
  • edx.org Free online courses from MIT, Harvard, and other excellent schools that mirror actual undergraduate courses, with labs, graded tests, online real-human interaction, and the possibility of earning a certificate. In particular, you might be interested in:
    • 7.00x Introduction to Biology: The Secret of Life, taught by Dr. Eric Lander, from the Human Genome Project
    • 6.00x Introduction to Computer Science and Programming
  • ocw.mit.edu Free material from many, many MIT classes, including video lectures. In particular, you might be interested in:
    • Biology highlights for high school
    • 7.01SC Fundamentals of Biology, also taught by Dr. Eric Lander, along with Dr. Robert Weinberg, who made huge contributions to cancer research (both won 3 million dollars this past February for their research)
    • 6.00SC Introduction to Computer Science and Programming
  • codecademy.com Free interactive programming classes online.
  • wikipedia.org/wiki/genomics Excellent introductory information. Follow the links!
If you have questions, if you do a presentation, or if you try a DNA extraction, alone or with a class, and you comment or email me about what happened it would make me very happy—especially if you are adventurous and try a DNA extraction from something new. )

TOP 10 iPad Apps for Engineers

Posted date: 9:33 PM / comment : 0 , ,

Now that the new iPad has been launched, several new apps that take advantage of the third-generation tablet's high-definition screen will also surface before the device reaches Apple stores. While most of us are aware of apps such as Angry Birds, Spotify, or Foursquare, how many are familiar with apps that could make an engineering task easier?
"Apps help engineers do simple things quicker," says 26-year-old Daniel Holmes, a professional engineer with a major firm. Engineering is specific to the situation, says Holmes, who specializes in hydraulics. "If you want to use a quarter-inch bolt and need to understand if it can withstand a certain amount of force or what size drill to use, apps can help you do that calculation quickly," he says. Holmes and his partner have developed iEngineer, an app that offers a database of screw and bolt information. Currently an iPhone app, iEngineer will be available for the iPad soon, he says.
Dr. David Knezevic is a computational science lecturer at the Harvard Institute for Applied Computational Science and was previously a post-doc in MIT's Department of Mechanical Engineering, which developed an application to perform simulations on a smart phone. "Apps liberate engineers to do analysis on site, away from their desktop," he says. "When you are on site and you get new data, you can test it and do some quick engineering calculations right there on your tablet." Mobile as a platform, says Knezevic, is becoming more and more appealing and ubiquitous as phones and tablets are becoming more and more popular. "Apps will become more appealing as time goes on. It's an irreversible trend," he adds.

The iEngineer iPad app offers a database of screw and bolt information.
With new apps being launched daily, it's hard to keep track of what's popular in any specific category. There are many cool apps designed with engineers in mind, but broadly they can be categorized into apps for engineering calculations, design simulations, or reference. If you are a mechanical engineer or aspiring to be one, you might find these 10 iPad apps useful.
HVAC Professional
HVAC Professional Formulator includes all 200 formulas of the HVAC Fomulator and adds 18 charts, as well as the complete International Mechanical Code. It has a variety of sections including air change, airside, boilers, BTU conversions, ductwork, energy values, heating design, heating requirements, humidity, loads, pumps, steam, temperature, waterside systems, and area calculations.
LuxCalc Fluid Prop
This is a mechanical engineering app that allows engineers involved in thermal analysis to quickly and accurately (within 5%) calculate the thermophysical properties of common fluids found in heat transfer books such as specific heat, absolute viscosity, kinematic viscosity, thermal expansion, and more, for a user-specified temperature.
10 iPad Apps for Engineers - Technology & Society
HVAC Professional Formulator includes all 200 formulas of the HVAC Formulator and adds 18 charts, as well as the complete International Mechanical Code.
Graphing Calculator
Useful for engineers and scientists, the Graphing Calculator turns the iPad into a high-resolution function plotter and scientific calculator. Some of its features include: quickly plotting and tracing multiple equations on the same graph, custom keyboard to speed up entering equations, pinch to zoom and drag or slide for scrolling the graph in real time, taking screen shots, and e-mailing graphs to yourself.
TouchCalc
Good for number crunching and analysis, this colorful calculator offers three different modes. The scientific mode allows standard functions and operations like the basic arithmetical operations, power, logarithm, roots, and more. The bit/integer mode offers logical operations on bit level. The statistics mode helps you create a sample by adding several values and then calculate mean, median, quantil values, variance, standard deviation, and range, among others.
Mechanical Engineer
This app contains over 300 mechanical engineering formulas. There are over 300 additional conversion formulas in the program as well as 70 area formulas. Major areas covered in the program include: bearings, belts, boilers, brakes, clutches, elevators, gears, fluid power, heat transfer, internal combustion, kinetic energy, power plants, shafts springs, and vehicle drive.
Engineering Professional
This app is a good reference tool for any engineering student as it combines over 650 formulas in chemical, civil, electrical, environmental, hydrology, and mechanical engineering that allow engineers to determine everything from calculations on shafts to calculation on loads on beams. In addition, there are 100 conversion formulas, as well as a section for determining area formulas.
Engineering Unit Conversion
This unit conversion tool is specifically designed for engineers, scientists, and students. It offers dimensions engineers need on a daily basis with all the units they commonly use. They can also input negative values when required for temperature and gauge pressures.
Finger CAD
FingerCAD is a computer-aided design (CAD) application for technical drawing. With FingerCAD, engineers can draw houses, bridges, mechanical components, geometrical figures, and everything they can draw with a common PC CAD.
TurboViewer X
TurboViewer X is a DWG viewer that supports both 2-D and 3-D CAD DWG files. The app allows multi-touch navigation as you pan, zoom, and 3-D orbit around your DWG and DXF files. To view drawing files, you can send an e-mail with the DWG or DXF attachments directly to your iPad. Drawing files can also be viewed through FTP, Dropbox, iCloud, and other cloud-based storage systems.
AutoCAD WS
Autodesk's app lets engineers view, edit, and share DWG drawings through the iPad. Engineers can accurately annotate and revise drawings while they are on location in the field, in meetings, or out of the office. They can also work with local versions of designs when they don't have an Internet connection, and easily open DWG, DWF, and DXF files received as email attachments.

Chinese Chemists Invent Water-Jet Printer

Posted date: 10:38 PM / comment : 0 , , ,

Goodbye, Ink: Chinese Chemists Invent Water-Jet Printer

Printer ink makers and ink refilling stations may soon have an unexpected competition from a printer which uses H20 and not ink. The technology was developed by a team of chemists from China.
What makes the technology work is the paper that was treated with an invisible dye that colours upon exposure to water and later disappears. It uses a dye compound called oxazolidine that gives a clear, blue print in less than one second upon application of water.
Within a day, the used paper fades back to white which makes it reusable.
At temperature lesser than 35 degrees Celsius, the print would fade away in 22 hours, while at higher temperature, it would fade faster. The technology is ideal for documents that are printed to be read once and then discarded.
Sean Xiao-An Zhang, the chemistry professor at China's Jilin University, who supervised the work on the water-jet printer, estimated that about 40 per cent of office prints are eventually thrown to the garbage bin after one reading.
Mr Zhang estimates that based on 50 times rewriting, the cost would be only 1 per cent of inkjet prints. Reusing the paper only 12 times would bring down the cost of one-seventeenth of the cost of inkjet print.
The technology does not require changing a printer but only replacing the ink in the cartridge with H20, using a syringe.
The team published the result of their experiment in the Nature Communications journal.

Real Faces or distorted

Posted date: 7:27 PM / comment : 0 , , ,

Keep Your Eyes on the Cross



Why this is Happening?
Your eyes like change.
The effect in this illusion is based on the fact that your visual cortex, the vision center of your brain, is always trying to find new information. Information that is determined to not be new is essentially ignored. This habituation, as it's called, occurs even over very short durations. Your visual cortex determines that what it's seeing is "normal" and it expects that to stay the same. When that "normal" becomes something different, your brain exaggerates the difference between its perceived "normal" and what you're actually seeing.
You'll notice that there is a lot of variance in the shapes of the faces you see and the shape and size of the features. When your brain adapts to a person with a round, thin face, if the next person has a wide, square face then it looks even wider and squarer.
If a nose is slightly crooked in one image, it will look crooked the opposite direction in the next image, because your brain expects "crooked to the left" to be normal. Anything that is not "crooked to the left" must be crooked to the right.
It occurs when you're looking at the dot cross because moving your eyes resets this effect (which is why it doesn't happen in everyday life), and because your peripheral vision is better at determining general shapes rather than details. Your peripheral vision looks at the general shapes of these faces and warps your perception to match those general shapes to what it expects them to be. If those faces were right in front of you, it would be 1) harder to keep your eyes focused on one point because of all the dramatic change directly around that point, and 2) easier for your brain to look at the details and adapt to the differences.
It should be noted that this habituation effect also contributes to the reason why illusions such as inverted color illusions work (notice that when you move your vision the color goes away). Your brain adjusts to the colors, and when they change suddenly your brain exaggerates the difference.

My Reaction after watching this.

Celebrating 25 Years of Not Getting Lost Thanks to GPS

Posted date: 1:25 PM / comment : 0 , , ,

If there was ever a justification needed for space technology, it’s that it keeps people like me from constantly being lost. These days, my smart phone is much better than me at getting around thanks to a fleet of satellites that tells it where it is at all times.
Though not a particularly romantic anniversary, today marks 25 years since the first satellite in the U.S. Global Positioning System launched from Cape Canaveral, beginning the set up for one of the wonders of the modern world. In the two and a half decades since then, GPS has become inextricably embedded into just about everything we own, finding use in cartography, smart phone apps, geotagging and geocaching, disaster relief, and hundreds of other applications, while simultaneously raising privacy concerns.
GPS relies on at least 24 satellites flying 20,000 kilometers overhead in one of six different orbital paths, tracing out what looks like a toy model of an atom. With their solar panels extended, each of these 1-ton satellites is about the same size as a giraffe. At any given moment, each satellite beams out a signal identifying itself and giving its time and location.
Your GPS-enabled phone or car captures that signal and compares the time it was received to the time it was transmitted. A quick calculation involving the speed of light allows the device to figure out the distance to that satellite. If you have your distance to two or three satellites, you can triangulate your position on the Earth. When all the GPS satellites are working, a user always has at least four in view, allowing them to determine things like altitude, speed, and direction.
In order to properly triangulate, GPS requires extremely accurate timekeeping, which is why each satellite carries an atomic clock. The satellites are also some of the most important technology using lessons learned from Einstein, who taught us that clocks outside a gravitational well will run faster than those inside of it because of the warping of space-time. An opposite effect comes from the fact that GPS satellites move at 14,000 kilometers per hour (0.001 percent the speed of light), meaning that they experience a slight time dilation making their clocks run slow relative to one at rest on the ground. The two effects taken together mean that the clock on a GPS satellite runs about 38 microseconds faster each day than ones here on Earth. GPS requires accuracy of 20 to 30 nanoseconds (one microsecond is 1,000 nanoseconds), so both effects are part of the calculation determining how far away each satellite is at any given time.
The idea behind GPS comes from the very beginnings of the Space Race. In 1957, the Soviet’s newly launched Sputnik satellite emitted a characteristic radio beep that could be tuned in to as the object passed overhead. While the rest of the U.S. was freaking out, two scientists at the Applied Physics Laboratory realized they could use those transmissions to pinpoint where the satellite was. As Sputnik approached, its radio signals would get compressed a little, shortening their wavelength, and as it receded, the wavelengths would lengthen. This is known as the Doppler effect and can easily be heard as an ambulance speeds toward you, the pitch of its siren getting higher.
The APL scientists used UNIVAC, one of the first commercial computers in the U.S., to figure out Sputnik’s orbit. A year later, they were asked to do the opposite problem: Find out where someone was on Earth based on the location of an overhead satellite. This was soon taken up by the Department of Defense’s Advanced Research Projects Agency (later named DARPA, the agency responsible for developing the internet), which launched satellites starting in 1964 as part of the TRANSIT program, the first satellite navigation program. The U.S. Navy was the main user of the TRANSIT satellites, using them to provide location information for their missile submarines.
Developing, launching, and maintaining the satellites necessary for a full GPS system was horrendously expensive (eventually costing roughly $8 billion in today’s dollars). If it hadn’t been for the Cold War and the fact that the U.S. needed to launch nuclear missiles from anywhere and everywhere, GPS might never have happened. The paranoid U.S. military wanted to make sure they would be able to respond to a Soviet nuclear attack even if some of its nuclear arsenal was destroyed. It wasn’t enough to have aircraft bombers and land-based intercontinental ballistic missile launchers. Submarine-launched ballistic missiles were needed to provide a counterattack from the sea. (The Soviets, of course, had similarly spread-out countermeasures.)
But submarines needed to accurately know their position before launching a missile in order to hit their target. The Navy had TRANSIT for this. Working in parallel throughout the 1960s, the Air Force developed a similar concept called MOSAIC for their bombers and the Army launched satellites under the SECOR program that could determine the location of a unit somewhere on the globe.
By 1973, the branches of the U.S. military realized they could combine their ideas and come up with something superior to all three. In September of that year, the top brass met at the Pentagon and came up with what would eventually become known as the Navigation System Using Timing and Ranging program, called Navstar-GPS, which was later shortened to just GPS. Between 1978 and 1985, the military launched 11 satellites (10 of which worked) to test the new GPS system.
An unlaunched GPS unit, which looks like probably the most satellitey satellite ever. Image: Scott Ehardt
After Korean Air Lines flight 007 was shot down in 1983 for wandering into prohibited U.S.S.R. airspace, President Reagan promised that GPS would be opened up for civilian use on passenger aircraft once it was completed. The first GPS satellite in the modern fleet launched on Feb. 14, 1989. The Air Force had planned to use the space shuttle for this launch in 1986 but was delayed by the Challenger disaster and eventually used a Delta II rocket. The full GPS fleet was completed in 1994 and now at least 32 satellites are in orbit to provide redundancy. During the same time, the Russians developed and launched GLONASS, which works on principles similar to GPS, and is currently the only alternative location-finding system in the world.
At its beginning, the U.S. military feared that GPS technology would be used by enemies, and purposely degraded civilian information so that it could only provide accurate location information to within 100 meters. In 2000, President Clinton had this feature turned off and now civilian devices are usually accurate to within 5 to 10 meters. The European Union and China are currently building their own global navigation systems, known as Galileo and Beidou, respectively, that will serve as further alternatives to GPS in the coming decade. It seems likely that folks in the future will never have to worry about being lost again.

Lead Can Be Turned into Gold

Posted date: 11:32 AM / comment : 0 , ,

Fact or Fiction?: Lead Can Be Turned into Gold

Particle accelerators make possible the ancient alchemist’s dream—but at a steep cost

gold
For hundreds of years alchemists toiled in their laboratories to produce a mythical substance known as the philosopher’s stone. The supposedly dense, waxy, red material was said to enable the process that has become synonymous with alchemy—chrysopoeia, the metamorphosis, or transmutation, of base metals such as lead into gold.
 
Alchemists have often been dismissed as pseudoscientific charlatans but in many ways they paved the way for modern chemistry and medicine. The alchemists of the 16th and 17th centuries developed new experimental techniques, medicines and other chemical concoctions, such as pigments. And many of them "were amazingly good experimentalists,” says Lawrence Principe, a chemist and science historian at Johns Hopkins University. “Any modern professor of chemistry today would be more than happy to hire some of these guys as lab techs.” The alchemists counted among their number Irish-born scientist Robert Boyle, credited as one of the founders of modern chemistry; pioneering Swiss-born physician Paracelsus; and English physicist Isaac Newton.
 
But despite the alchemists’ intellectual firepower and experimental acumen, the philosopher’s stone lay forever out of reach. The problem, Principe says, is that the alchemists did not yet know that lead and gold were different atomic elements—the periodic table was still hundreds of years away. Believing them to be hybrid compounds, and therefore amenable to chemical change in laboratory reactions, the alchemists pursued the dream of chrysopoeia to no avail.
 
With the dawn of the atomic age in the 20th century, however, the transmutation of elements finally became possible. Nowadays nuclear physicists routinely transform one element to another. In commercial nuclear reactors, uranium atoms break apart to yield smaller nuclei of elements such as xenon and strontium as well as heat that can be harnessed to generate electricity. In experimental fusion reactors heavy isotopes of hydrogen merge together to form helium. (An element is defined by the number of protons in its nucleus whereas an isotope of a given element is determined by the quantity of neutrons.)
 
But what of the fabled transmutation of lead to gold? It is indeed possible—all you need is a particle accelerator, a vast supply of energy and an extremely low expectation of how much gold you will end up with. More than 30 years ago nuclear scientists at the Lawrence Berkeley National Laboratory (LBNL) in California succeeded in producing very small amounts of gold from bismuth, a metallic element adjacent to lead on the periodic table. The same process would work for lead, but isolating the gold at the end of the reaction would prove much more difficult, says David J. Morrissey, now of Michigan State University, one of the scientists who conducted the research. “We could have used lead in the experiments, but we used bismuth because it has only one stable isotope,” Morrissey says. The element’s homogeneous nature means it is easier to separate gold from bismuth than it is to separate gold from lead, which has four stable isotopic identities.
 
Using the LBNL’s Bevalac particle accelerator, Morrissey and his colleagues boosted beams of carbon and neon nuclei nearly to light speed and then slammed them into foils of bismuth. When a high-speed nucleus in the beam collided with a bismuth atom, it sheared off part of the bismuth nucleus, leaving a slightly diminished atom behind. By sifting through the particulate wreckage, the team found a number of transmuted atoms in which four protons had been removed from a bismuth atom to produce gold. Along with the four protons, the collision-induced reactions had removed anywhere from six to 15 neutrons, producing a range of gold isotopes from gold 190 (79 protons and 111 neutrons) to gold 199 (79 protons, 120 neutrons), the researchers reported in the March 1981 issue of Physical Review C.
 
The amount of gold produced was so small that Morrissey and his colleagues had to identify it by measuring the radiation given off by unstable gold nuclei as they decayed over the course of a year. In addition to the several radioactive isotopes of gold, the particle collisions presumably produced some amount of the stable isotope gold 197—the stuff of wedding bands and gold bullion—but because it does not decay the researchers were unable to confirm its presence. “The stable isotope would have to be observed in a mass spectrometer,” Morrissey says, “but I think that the number of atoms was, and is still, below the level of detection by mass spec.”
 
Isolating the minute quantities of gold would be even more difficult using lead as a starting material, but smashing high-speed nuclei into a lead target would indeed complete the long-sought transmutation. Some of the collisions would be expected to remove three protons from lead, or one proton from mercury, to produce gold. “It is relatively straightforward to convert lead, bismuth or mercury into gold,” Morrissey says. “The problem is the rate of production is very, very small and the energy, money, etcetera expended will always far exceed the output of gold atoms.”
 
In 1980, when the bismuth-to-gold experiment was carried out, running particle beams through the Bevalac cost about $5,000 an hour, “and we probably used about a day of beam time,” recalls Oregon State University nuclear chemist Walter Loveland, one of the researchers on the project. Glenn Seaborg, who shared the 1951 Nobel Prize in Chemistry for his work with heavy elements and who died in 1999, was the senior author on the resulting study. “It would cost more than one quadrillion dollars per ounce to produce gold by this experiment," Seaborg told the Associated Press that year. The going rate for an ounce of gold at the time? About $560.
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