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November 30, 2006

An Exact Science

As most students of my generation, I took a course in biology in my sophomore year of high school. Chemistry was reserved for junior year, and physics was taught in senior year. This was a logical progression in the 1960s, since biology was a descriptive science that required almost no mathematics. It was like a Victorian pin board of butterflies, arrayed by size or color, but never quantified by any numbers or theory. By the time my daughter took high school biology in the early part of this century, the entire aspect of biology had changed to the point at which I had difficulty reading her textbook. Biology had become an exact science.

Ernest Rutherford (1871-1937), a preeminent physicist of his age (Rutherfordium Rf, element 104, is named after him), and winner of the 1908 Nobel Prize in Chemistry, once said, "All science is either physics or stamp collecting." Many disciplines of science progressed from a descriptive stage (stamp collecting) to an exact science, for which physics is the archetype. Astronomy, from the Latin astrum (star or constellation) and nominare (to name), originally was just finding and naming stars. In the seventeenth century, Johannes Kepler's laws of planetary motion added a touch of mathematics. Eventually, spectrographs were fitted to larger and larger telescopes, stars were described by more and more numbers, and astronomy became an exact science. Eventually, astronomy spun-off the very mathematical subfield of astrophysics. Much the same course was followed by geology and meteorology.

The quantization of biology was assisted by physicists who crossed over to the discipline. Max Delbruck, a theoretical physicist who received his Ph.D. in 1930, was encouraged to enter biology by no less than Niels Bohr. He went on to win the 1969 Nobel Prize in Physiology or Medicine for work on the replication mechanism and genetics of viruses. Another distinguished physicist who migrated to biology was Francis Crick, who with James Watson, Rosalind Franklin, and another physicist, Maurice Wilkins, deciphered the role of DNA in organisms. Crick originally began a physics Ph.D. on the viscosity of water at high temperatures, but abandoned this for defense work during World War II. After the war, Crick migrated into biology research along with a large troop of physical scientists.

The transition of biology from a descriptive to an exact science was not wholly welcomed by all biologists. Many decried this paradigm shift as mere "physics envy," in analogy to a Freudian theory that would shock any feminist. The alleged aversion of biologists to mathematics has spawned many humorous stories. One of the more interesting accounts is how biologists mix chemical solutions [1]. Instead of weighing reagents, they use descriptive categories for quantity of matter

• Some.
• A bunch.
• A whole bunch.
• A ton.
• All of it.
• See if somebody else has any.
• We'll have to buy some more.

At least two of my colleagues in Morristown have degrees in Biology. I'm happy to say that their laboratory technique is far superior!

1. Physics envy among biologists: fact or fiction?
2. The nature of scientific truth
3. Biology and 'physics envy'
4.Erwin Schrodinger, "What is Life? (1944).

November 29, 2006

Black Gold

Black gold was a common colloquial term for crude oil. The term was used in the theme song for The Beverly Hillbillies, 274 episodes of which aired on the CBS television network from 1962-1971. The show must have had a subtle effect on me, since I carry a fancy leather lunch box [1] to work.

There's another black gold in the news, this time made from real gold. Chunlei Guo, a professor at the University of Rochester found that a short, intense pulse of laser light from a femtosecond laser transforms a gold surface into a convoluted nanoscale topography of large surface area that is optically absorbant. The process works for other metals, not just for gold, and aside from possibly increasing the efficiency of solar cells, the increased surface area could be applied to catalysis and battery electrodes.

Although Guo's laser process is novel, black gold is not new. One of my colleagues prepared black gold in my laboratory more than ten years ago by another process, evaporation of gold in the presence of a rarified inert atmosphere. When gold is evaporated under an argon or nitrogen pressure of about 750 millitorr, the gold atoms cool and cluster before attaching to a substrate. Aside from Guo's process, there are four processes for preparing black gold.

• Electrochemical etching
• Assembly of gold colloidal particles
• Thermal evaporation in an inert atmosphere (as above)
• Laser ablation

The later laser technique differs from Guo's femtosecond laser approach. A high powered laser irradiates the back side of a transparent substrate coated with a thin metal layer. The metal is ablated by the absorbed radiation, and it is deposited onto a nearby substrate.

1. Beverly Hillbillies' term for an attache case.
2. Ultra-intense laser blast creates true 'black metal'.
3. John Lehman, et al., "Gold-black coatings for freestanding pyroelectric detectors," Meas. Sci. Technol., vol. 14 (2003), pp. 916-922.
4. W. Becker, R. Fettig, and W. Ruppel, "Optical and electrical properties of black gold layers in the far infrared," Infrared phys. technol., vol. 40, no. 6 (Elsevier, 1999) pp. 431-445.
5. Chih-Ming Wang, Ying-Chung Chen, Maw-Shung Lee1 and Kun-Jer Chen, "Microstructure and Absorption Property of Silver-Black Coatings," J. Appl. Phys., Vol. 39, Part 1, No. 2A (15 February 2000), pp. 551-554.

November 28, 2006

Ettore Majorana

Italy has produced many famous physicists. These include Galileo Galilei (1564-1642), Luigi Galvani (1737-1798), Alessandro Volta (1745-1827), Guglielmo Marconi (1874-1937), Emilio Segrè (1905-1989), and Enrico Fermi (1901-1954). Also numbered among these is Ettore Majorana (b. 1906), who is somewhat lesser known, since he did no physics after age 31. Majorana went missing in 1938 on a boat trip from Palermo to Naples, and a body has never been found. This year marked the centenary of his birth.

Majorana was a gifted mathematician who became entangled with quantum mechanics in its early years while working with Fermi's group in Rome; and also with Heisenberg in Germany. During his short professional career, he worked on the theory that neutrinos have mass, an idea getting much attention in the last few decades. He also thought that mass may have a small shielding effect on gravity, an unproven conjecture that may explain some properties of the universe. Majorana was also the first to postulate the existence of the neutron, but he didn't publish this idea. He thought that the idea of the neutron was an obvious interpretation of experimental results and not worth publication. This episode highlights a character fault of Majorana similar to that of Grigori Perelman. Perelman, a reclusive Russian mathematician, refused the award of a Fields Medal because he valued his own work less than it was valued by others. Fermi, winner of the 1938 Nobel Prize in Physics, often praised Majorana. Fermi is quoted as saying, "There are many categories of scientists, people of second and third rank, who do their best, but do not go very far. There are also people of first class, who make great discoveries, fundamental for the development of science. But then there are the geniuses, like Galilei and Newton. Well, Ettore Majorana was one of them ..."

So, what happened to Majorana? Fermi remarked to his wife upon Majorana's disappearance, "Ettore was too intelligent. If he has decided to disappear, no-one will be able to find him." One theory, by famed Italian author, Leonardo Sciascia, is that Majorana decided to disappear since he understood the secret of nuclear explosives long before his colleagues, and he didn't want to be a part of a government effort to build an atomic bomb. Sciascia cites rumors that Majorana may have been sighted in Argentina in the 1950s. There were also reports of a homeless man in Italy who claimed that he was once a famous physicist. A recent interpretation [4] is that, like Schrödinger's cat, Majorana decided to ascend to a superposition of states in which he was both alive and dead at the same time. There is a fine line between genius and madness [5], and this idea may have appeared logical to Majorana.

1. Ettore Majorana Web Site.
2. Ettore Majorana: genius and mystery (Cern Courier).
3. Leonardo Sciascia, "La Scomparsa di Majorana, English translation: "The Moro Affair and The Mystery of Majorana," (Carcanet, 1987, ISBN 0-85635-700-6).
4. Zeeya Merali, "The man who was both alive and dead," New Scientist, vol. 191, no. 2563 (5 August 2006), p. 15.
5. Sean Connery fans will enjoy the movie, A Fine Madness (1966, Irvin Kershner, Director), in which Connery plays Samson Shillitoe, a slightly mad poet.

November 17, 2006

Statistics and Vacations

There's a story about a Six-Sigma Black Belt who was so good at statistical analysis that he had completed all his tasks for the month a week early. Trying to keep busy, he started doing correlations between any data sets he could find. He found that there was a strong correlation between his vacation schedule and company profit. When he was away, the company did better. He decided that he could reach his true true potential only by leaving the company.

I've decided to take all of next week as vacation, but unlike our analytical friend, I've decided to return. I'll have another blog entry posted on Tuesday, November 28, 2006. I'll also post the difference in Honeywell stock price between the start and end of my vacation. You be the judge.

1. Wikipedia Article about Six-Sigma.

November 16, 2006

Leonid Meteor Shower This Weekend

The annual Leonid Meteor Shower is predicted to peak at about 11:45 PM Eastern Standard Time on Saturday, November 18, 2006. The shower is expected to be visible only in the sector of the Earth between Western Europe, where it will peak at 4:15 GMT on Sunday, and the eastern parts of North America. The southernmost regions for observation are Brazil and Western Africa. The peak is not expected to be visible in the central, or western, regions of the US. There are likely to be at least thirty meteors per hour in the hour around the peak. Predictions of shower intensity have never been very accurate, and this year they range from 35 - 150 meteors per hour. The Leonids are typically fast (71 km/sec), faint meteors. A very dark, cloudless sky is required for observation.

If you're on the US east coast, look towards the eastern horizon. Observers in Europe will see the shower high over the southeastern horizon. The reason that the central and western regions of the US are out of luck is because the constellation Leo, from which the meteors appear to come, will be below the horizon.

The Leonid Meteor Shower occurs when the earth passes through debris of Comet 55P/Tempel-Tuttle, which orbits the sun with a thirty-three year period. Meteors are usually sand-sized grains of rock, so a little debris goes a long way. This year, Earth will pass through the debris trail left during the comet's 1932 passage around the sun. Since this was just two orbits ago, there are hopes of sufficient debris for an outburst of many meteors per hour. The Leonids were quite spectacular in 1966, 1999, 2001 and 2002, although in different parts of the world. I observed the 1966 Leonids (peak rate of about a thousand per hour) as a teenager. The 1833 Leonids had a spectacular rate of a hundred thousand meteors per hours, and many people thought it was the end of the world.

Before the eighteenth century, it was thought that meteors were a terrestrial phenomenon, and meteors originated in the upper atmosphere. The first scientific investigation of meteors was done by Heinrich W. Brandes and Johann F. Benzenberg of the University of Göttingen. They observed meteors from two different locations and found that meteors first become visible at an altitude of about 100 km; and that they traveled at tens of kilometers per second. These observations pointed to an extraterrestrial origin.

If you miss the Leonids, don't fret. There is always a background rate of about 5 - 10 meteors per hours for a few days before and after the shower. Also, year-round there are sporadic meteor falls of about three meteors per hour that are not associated with any meteor shower. It's just random space debris. It's also possible to detect meteors with an FM radio, as described here.

While on the subject of comets, Halley's Comet, the most famous comet, is the cause of two meteor showers, the Eta Aquarids (May) and the Orionids (October). Mark Twain was born during the 1835 apparition of Halley's comet, and he wrote in his autobiography that he would leave the world at its next apparition, which he did in 1910.

1. Leonids (Wikipedia).
2. Joe Rao, "Strong Leonid Meteor Shower Expected Nov. 18" (SPACE.com)
3. The Leonid Meteors 2006 - Armagh Observatory.
4. Leonid History (Gray Kronk)
5. Comet 55P/Tempel-Tuttle and the Leonid Meteor Shower.

November 15, 2006

The Shape of the Universe

There's a joke about the way physicists approach problems. A government agency sent out a call for proposals to increase milk production. It received the expected proposals about pharmacology, genetic engineering, etc., but there was an unexpected proposal from a physicist. Interested, they opened the envelope and started to read, "Assume a spherical cow..."

The universe has always been considered to be spherical. Since the discovery of the finite speed of light, we've known that we sit in the center of an "event horizon" beyond which we have no knowledge. For all practical purposes, our knowable universe is a sphere, but recent measurements of an anisotropy in the cosmic microwave background radiation indicate that, at its start, the universe was ellipsoidal.

The cosmic microwave background radiation was discovered at Bell Labs by Arno Penzias and Robert Wilson. Much like Karl Jansky, the father of radio astronomy, who also worked at Bell Labs, they were looking for noise that would interfere with telecommunications. In his search for noise, Jansky discovered extraterrestrial radio sources in 1933 at a frequency of 20.5 MHz. Penzias and Wilson were looking at much higher frequencies in the microwave range, and they discovered an omnidirectional signal they could not identify. Fortunately, Princeton University is a short drive from Bell Labs, and they were able to confer with astrophysicist P. J. E. Peebles, who suggested they were seeing the cooled blackbody radiation from the Big Bang. Penzias and Wilson won the 1978 Nobel Prize in Physics for their discovery.

Now, careful measurements with the Wilkinson Microwave Anisotropy Probe, an instrument in a satellite launched in June, 2001, have shown that there is a quadrupole anisotropy in the cosmic background radiation. A team of Italian physicists, Leonardo Campanelli, Paolo Cea, and Luigi Tedesco [1], have shown that this quadrupole anisotropy can be explained by a one percent ellipsoidal eccentricity in a feature of the early universe called the surface of last scattering. This surface represents the boundary of the universe about 380,000 years after the Big Bang.

What's a part of the job description for a Nobel Prize winning physicist? Cleaning pigeon droppings from a microwave horn antenna! That's what Robert Wilson did, along with checking the conductance across seams, when he was trying to eliminate that pesky noise from his measurements.

1. L. Campanelli, P. Cea, and L. Tedesco, "Ellipsoidal Universe Can Solve the Cosmic Microwave Background Quadrupole Problem," Phys. Rev. Lett. vol. 97 (September 29, 2006)
2. Phil Schewe and Ben Stein, "Ellipsoidal Universe" (AIP Physics News, No. 794, October 3, 2006)

November 14, 2006

Tom Swift and His Electric Thermostat

Among the things that got me interested in science was the Tom Swift book series, written by Victor Appleton II (a pseudonym used by various ghostwriters), and published by Grosset and Dunlap. Tom Swift, son of millionaire industrialist, Tom Swift, Sr., got to experience the inventions of his father's company first hand. He also had a role in inventing things himself. Among the books I read from this series were

• Tom Swift and His Atomic Earth Blaster (1954)
• Tom Swift and His Giant Robot (1954)
• Tom Swift and His Outpost in Space (1955)
• Tom Swift in The Caves of Nuclear Fire (1956)
• Tom Swift and His Ultrasonic Cycloplane (1957)
• Tom Swift and His Space Solartron (1958)

I didn't realize at the time that these books were the second generation of Tom Swift books. The Original Tom Swift series featured Tom Swift, Sr. as a boy inventing things in a fictional town, Shopton, in Upstate New York (I'm from Utica in Upstate New York). Actually, Upstate New York (the part of New York State that is not New York City, Long Island, Westchester, and Rockland Counties) has always been a hotbed of technology. George Eastman, founder of Eastman Kodak in 1881, was born in Waterville, about twenty miles from Utica. The General Electric Company was founded in 1892 in Schenectady, New York, with the merger of several electric companies, including Thomas Edison's company. Xerox was founded in 1906 in Rochester, New York.

Young Tom Swift may have been modeled on an actual Upstate New York inventor - Glenn Hammond Curtiss, early aviator, and the Curtiss of Curtiss Wright Corporation. Hammondsport, New York, was Curtiss' home town, and there are similarities to Shopton, Tom Swift's fictional home. The parallels between Tom Swift and Curtiss were examined in the 1982 book, "Tom Swift & Company," by Jack Dizer, a retired engineering professor from Utica.

The original Tom Swift Series was published from 1910-1941. The series I read as a child, the New Tom Swift Jr. Adventures, was published from 1954-1971. This was followed by a Third Tom Swift Series (1981-1984), a Fourth Tom Swift Series (1991-1993), and presently, the Tom Swift: Young Inventor Series (2006-Present). Steve Wozniak, who founded Apple Computer with Steve Jobs, says he read Tom Swift as a child. The Woz says that Tom Swift appealed to him because of Tom's creative freedom, scientific knowledge, and his ability to solve problems. Also, as epitomized by Wozniak himself, are the potential financial rewards of invention.

The Tom Swift of my generation was way ahead of his time. He launched a space station into orbit in 1955, and he landed on the moon in 1958. One thing of interest to materials scientists is an alloy, osmiridium, he used for his Sea Dart submarine. This was an alloy of osmium and iridium with strength to withstand water pressure at great depths. Actually, osmiridium is an ore that contains osmium and iridium, but the osmium-iridium alloy system probably does have impressive properties (aside from a very high price). Osmium has a measured bulk modulus of 462GPa (higher than diamond), and a melting point of 3033oC. The solubility limit of iridium in osmium is more than 35 atomic percent.

Alas, the Honeywell thermostat was introduced in 1906, four years before the first Tom Swift book, thereby preempting a best seller, "Tom Swift and His Electric Thermostat."

1. Jeff Duntemann, "Tom Swift, Jr.: An Appreciation"
2. Earl Swift, "The Perfect Inventor."

November 13, 2006

The Fibonacci Sequence

Start with the numbers (1, 1). Add them together and append the result to the series to get (1, 1, 2). Continue appending the sum of the final two numbers indefinitely, and you get the Fibonacci Sequence (1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89... ). The algorithm to generate the sequence is quite short, but it's not the only algorithm.

If you expand 100/89 into decimal form, you get 1.1235955056..., and you see that the first five digits after the decimal point are the first five digits of the Fibonacci Sequence. At this point, that's not that interesting, and it could just be an interesting coincidence. Now, add two zeros to the numerator, and a nine before and after the denominator to get (1000/9899) = 1.0102030508132134559046368...

(Note - Your pocket calculator only has about 8-11 digits precision, so for this ratio, you'll need to remember how to divide using pencil and paper, or have access to a computer language with extended precision, such as Lisp, perl, or Mathematica)

Now, things look interesting. We've generated the first ten numbers of the Fibonacci Sequence if we take the digits two at a time. Doing this again (adding two zeros to the numerator, and an extra nine at the start and end of the denominator) to get 1000000/998999 gives us the first 15 Fibonacci numbers if we take the digits three at a time.

This method of generating the Fibonacci Sequence was discovered by James Smoak and published with Thomas J. Osler of the Rowan University Mathematics Department [1]. They proved that fractions formed by this method always produce the Fibonacci sequence. Another mathematician, Marjorie Bicknell-Johnson, extended their work by finding a formula to identify fractions whose decimal representations include other sequences [2]. Smoak, along with O-Yeat Chan, has published another paper that includes the fraction 10000/9801 = 1.0203040506...99, a sequence with all the number from 01 to 99 [3].

1. J. Smoak and T. J. Osler, "A magic trick from Fibonacci," College Mathematics Journal, vol. 34 (January, 2003), pp. 58-60. (Online copy available here).
2. M. Bicknell-Johnson, "A generalized magic trick from Fibonacci: Designer decimals," College Mathematics Journal, vol. 35 (March, 2004), pp. 125-126.
3. O-Y. Chan and J. Smoak, "More designer decimals: The integers and their geometric extensions," College Mathematics Journal, vol. 37 (November, 2006), pp. 355-363.
4. Ivars Peterson, "Designer Decimals," Science News Online, vol. 170, no. 19 (Nov. 4, 2006)

November 10, 2006

Women in Science and Engineering

Harvard University President (now Past-President), Lawrence H. Summers, started quite a controversy at the beginning of 2005 with statements he made at the National Bureau of Economic Research Conference on Diversifying the Science & Engineering Workforce, January 14, 2005. His remarks were interpreted by many, and the press especially,to mean that girls aren't as intellectually capable as boys; and that women do not succeed at the highest levels of science because they lack the ability [1]. Although Summers published an apology [2], he was forced to resign the Harvard Presidency because of his comments, but the fact remains that there are few women in science and engineering.

If it's not Nature, then it must be Nurture. Young women have not been encouraged to pursue science and engineering as careers, and they have somehow been brainwashed into believing that mathematics is not for girls. Less than nine percent of working engineers, and less than sixteen percent of working scientists, in the U.S. are women. The statistics in Computer Science are more alarming. In high schools, only 20% of students taking the Advanced Placement examination in computer science are girls.

In a previous post, I mentioned Math Counts, an organization established to encourage mathematics in middle school education. My daughter's all-girls school participated in this program in grades 7-8 when she attended, and this is definitely one way to prime women for science and engineering careers. Her school had a very impressive science fair each year. You can view some of my daughter's science fair projects here.

The Society of Women Engineers was founded in 1950 as an educational and service organization that promotes engineering as a career for women. ExxonMobil has recently contributed $1 million to the Society of Women Engineers. girls inc. launched Operation SMARTSM (Science, Math, and Relevant Technology) in 1985. About a quarter of a million girls between the ages of eight and eighteen are being exposed to science and technology careers.

So, Honeywell scientists and engineers, volunteer as judges for school science fairs, and search the web for other volunteer activities in your area. Use the comments link below to share additional information on this topic.

1. Lawrence H. Summers, Remarks at NBER Conference on Diversifying the Science & Engineering Workforce (Cambridge, Mass., January 14, 2005).
2. Letter from President Summers on women and science (January 19, 2005).
3. Joyce Gannon, "Engineering a future for women" (Pittsburgh Post-Gazette, November 09, 2006)

November 09, 2006

Hydrogen-Fueled Funny Cars

Many of you may think the idea of using hydrogen to power vehicles is new, but I worked in this area twenty-five years ago [1-3]. At that time, the leading candidates for hydrogen storage were metal hydrides. LaNi5 is a prime example of these, since it absorbs hydrogen at just a few atmospheres pressure, and it releases it at atmospheric pressure. LaNi5 is a hydrogen "sponge," since the hydrogen is reversibly stored and withdrawn without a chemical reaction. All this sounds very nice, but LaNi5 has a formula weight of 432.372 grams/mole, and it absorbs less than five hydrogen atoms per LaNi5 formula unit. This gives a hydrogen density of only 1%.

Chemical storage of hydrogen is an option to get more hydrogen density. Of course, liquid hydrogen (100%) is the ideal, but cryogenic storage of liquid hydrogen is a problem. Also, the weight you should use to calculate hydrogen density should include the weight of the cryogenic container, so you would get less than 100%. Here are some other options:

• B2H6 (21%)
• Lithium Aluminum Hydride (10.5%)
• Barium Borohydride (10.6%)
• Lithium Borohydride (18.3%)
• Ammonia (17.6 %)
• Magnesium hydride (7%)

Most of these have one problem or another, especially "icity" (pyrophoricity and toxicity), or inefficient conversion to, or from, the hydride. The United States Department of Energy has set a 6% storage target for 2010, but the ability to quickly store and remove hydrogen is a key material property.

Recently, Frantisek Svec at Lawrence Berkeley National Laboratory and Jean Frechet at the University of California at Berkeley have achieved 1.5% storage of hydrogen in nanoporous polystyrene at atmospheric pressure. This climbed to 3.8% at forty atmospheres. The polystyrene, prepared by heating and chemical treatment, had pores of less than two nanometers. This is likely still larger than an optimum size, since the Van der Waals diameter of hydrogen is about 0.25 nm. This material is a true hydrogen "sponge," since no chemical reactions are involved.

Nanoporous polymers seems to be more commercially exploitable materials than carbon nanotubes, which are also promoted as a hydrogen sponge. I mentioned carbon nanotubes in a previous post on the MIT Energy Technology Initiative. Better materials may be on the way. Says Neil McKeown of the University of Cardiff, UK, "What is good about polymers is that you can tweak their chemistry to modify their absorption."

A Funny Car (a.k.a., Nitro-Fueled Funny Car) is a type of drag racer sanctioned by the National Hot Rod Association. These cars are fueled with a mixture of 85-90% nitromethane and 10-15% alcohol. As can be imagined, they are quite fast.

1. D.M. Gualtieri, K.S.V.L. Narasimhan, and T. Takeshita, Control of the Hydrogen Absorption and Desorption of Rare Earth Intermetallic Compounds, J. Appl. Phys. 47, 3432-3435 (1976).
2. D.M. Gualtieri and W.E. Wallace, Hydrogen Capacity and Crystallography of ErFe2-Based and ErCo2-Based Ternary Systems, J. Less Common Metals 55, 53-59 (1977).
3. D.M. Gualtieri and W.E. Wallace, Absorption of Hydrogen by LaNi5, NdCo5, and ErCo3 at Low Temperatures, J. Less Common Metals 61, 261-264 (1978).
4. Duncan Graham-Rowe, "Nanoporous material gobbles up hydrogen fuel" (NewScientist.com, 07 Nov 2006).
5. Florida Solar Energy Center (FSEC)

November 08, 2006

Ants in My Computer

Many years ago, I spilled Coke into my computer keyboard. This was the real, sugary Coke, not the Diet Coke I drink today. The keyboard was a huge, metal encased component, quite unlike today's thin keyboards, with enough room at the bottom for a sizeable pond of Coke. A few days later, I found that my keyboard was infested with ants! Of course, programmers have a long history with Coke, and my problem was not that uncommon. I had read (in a magazine - this was long before the internet) that a thorough rinse with de-ionized water, followed by a long drying time, would flush out the sugar and leave the keyboard still functional. Our laboratories have deionized water on tap, so the procedure was easy, and it worked.

Computer scientists have been using biomimetic techniques for optimization problems. Genetic algorithms are one example. Another is Ant Colony Optimization, or ACO. The ACO technique, invented in 1988, is a probabilistic method for finding optimum paths on graphs. ACO takes its inspiration from the way ants find a path between their colony and a food source. Several applications of ACO are network routing, routing of traces on a printed circuit board, and the Travelling Salesman Problem.

In their search for food, ants initially wander aimlessly, but when an ant finds food, it returns to its colony. During his return, the ant lays down a trail of a pheromone. Other ants, finding this trail, will tend to remain on it, find the food source, and intensify the trail on their return to the colony. Since the pheromone tends to evaporate, short paths are favored. Also, convergence to a locally optimal solution, which in this case could be going the too long way around a large rock, is less likely. An excellent review article on ACO is found in the recent issue of the IEEE Computational Intelligence Magazine[1].

Can other insects be useful in computer modeling? The honey bee, Apis mellifera, does a "waggle dance" to inform its hive mates about a food source. As soon as I read the term, "waggle dance," I realized this must be the way to model corporations.

In the early 1970s, my wife assisted with the identification and synthesis of bark beetle and deer pheromones with Robert M. Silverstein[3].

1. Marco Dorigo, Mauro Birattari, and Thomas Stuzle, "Ant Colony Optimization," IEEE Computational Intelligence Magazine, Volume 1, no. 4 (November, 2006), pp. 28-39.
2. Ant Colony Optimization Home Page
3. Robert M. Silverstein, G. Clayton Bassler, T.C. Morill, R.M. Silverstein, Terence C. Morrill, "Spectrometric Identification of Organic Compounds," (John Wiley & Sons Inc) ISBN: 0471634042.

November 07, 2006

Approval Voting

Today is Election Day in the US. Elections are traditionally scheduled for the first Tuesday after the first Monday in November. Plurality voting, in which you vote for one candidate from a slate of many, is used in most US elections, but it's not the only voting system. Approval voting, in which you can vote for as many candidates as you want (the ones that meet your approval), is another system. The difference is important only when there are more than two candidates for a position. Presently, approval voting is practiced by the Mathematical Association of America (MAA), The Institute of Management Science (TIMS), The American Statistical Association (ASA), and The Institute of Electrical and Electronics Engineers (IEEE). Is approval voting a better idea?

I was first introduced to the approval voting concept during the IEEE Election of 1986. Each year, the IEEE selects a president-elect who serves in that position for a year as a presidential trainee. He then becomes president the next year. The IEEE Board of Directors nominates two highly qualified candidates for president-elect, but other people may be nominated by petition. In 1986, Irwin Feerst became a petition candidate who ran on the principle that the IEEE should be an organization of "working" engineers, and not academics. He also wanted to restrict IEEE activities to US interests only. His campaign struck a chord with much of the IEEE membership. As a consequence, Feerst defeated one Board candidate, and came to within 242 votes (out of 52,405 cast) of defeating the other Board candidate. Although a majority of IEEE members sided with the ideals of the IEEE Board of Directors, the sentiments of the majority were split, since there were two Board candidates. As a consequence, the IEEE membership almost got a president-elect who did not have the same views as the majority. To prevent such a problem in the future, the IEEE's adopted approval voting in December, l987. When Irwin Feerst ran for president-elect in the l988 IEEE election, he was last in a field of four candidates.

Although there is less incentive for negative campaigning under approval voting, approval voting is not without its problems. One problem is that it is possible for the favorite candidate of a majority to lose an election. The reason for this is that candidates are not ranked when an individual votes. A voter only has the option to "approve," so all approved candidates are ranked equally, although voters would prefer their particular candidate to win. Some simple computer modeling will show that this is true, but a Gedankenexperiment is easier. Imagine an election of many candidates. Nearly everyone thinks candidate "A" is most qualified, but candidates "B" and "C" are acceptable, so everyone votes for just these three candidates; everyone, that is, except a solitary voter who casts just a single vote for candidate "C." Candidate "C" wins the election, everyone is satisfied, since they all voted for "C," but candidate "A," preferred by the majority, was not elected because of the whim of a single voter.

1. Steven J. Brams1 and Jack H. Nagel, "Approval voting in practice," Public Choice, Vol. 71, No. 1-2 (August, 1991), pp. 1-17.
2. Steven J. Brams and Peter C. Fishburn, "Approval Voting in Scientific and Engineering Societies," Group Decision and Negotiation, vol. 1 (April 1992), pp. 44-55.
3. Approval voting system(rangevoting.org)

November 06, 2006

Resistance is Futile

In a previous post, I reviewed the fundamental physical constants; specifically, the standard kilogram and efforts to replace a physical object as a reference for quantity of matter with a measurement that can be carried out in a laboratory. Electrical resistance is an extensive physical property measured in ohms. Surprisingly, electrical resistance, or its alternating current cousin, electrical impedance, is a fundamental constant in some systems. For example, the vacuum impedance is known to high precision as 376.730313461 ohms. It's the square root of the ratio of two fundamental constants, the permeability of free space (4pi x 10-7 H/m) and the permittivity of free space (8.8541878176 x 10-12 F/m).

Resistance as a fundamental unit is also manifest in the quantum Hall effect, discovered in 1980 by Klaus von Klitzing, who is presently at the Max Planck Institute for Solid State Research in Stuttgart, Germany. It is probably not surprising that the Hall effect should give a resistance standard, since it combines magnetism (permeability) with electricity (permittivity). Klaus von Klitzing was awarded the 1985 Nobel Prize in Physics for his discovery, and the unit of quantum Hall resistance is called the "von Klitzing constant" in his honor. The von Klitzing constant, the ratio of the Plank constant to the square of the electrical charge, has a value of 25,812.8 ohms.

The unit of electrical resistance, the ohm, is named after Georg Simon Ohm, who was also a German physicist. In 1827 he published a summary of what is now called Ohm's Law. The Borg, cyborg aliens in the Star Trek television series, lived by the motto, "Resistance is Futile."

1. K. von Klitzing, G. Dorda, and M. Pepper, Phys. Rev. Lett. 45, 494 (1980).

November 03, 2006

The Smell of Metal

With the notable exception of mercury, metals have a low vapor pressure at room temperature. For this reason, they should not have any smell. Although I haven't sniffed any mercury vapors (and don't intend to), it's not likely that mercury has a smell. However, we've all known from childhood that metal objects, such as coins, tableware and toys, have a recognizable "metallic" smell. How is that possible?

As reported in Nature, Dietmar Glindemann and his associates from the University of Leipzig, Germany, and the Virginia Polytechnic Institute and State University, have recently published a paper in the international edition of Angewandte Chemie concerning the origin of the metallic smell [1]. It all comes down to sweat; specifically, the reaction of human sweat with metals and the formation of organic compounds.

Glindemann became interested in the metallic smell after noticing the garlic-like aroma of iron after it had been handled with sweaty hands. He found that organophosphines were formed when the carbon and phosphorous impurities in iron interacted with the chemicals in sweat. In the Angewandte Chemie study, Glindemann and co-workers analyzed the vapors emitted when people handled iron, and they found aldehydes and ketones. One ketone in particular, 1-octen-3-one, has a mushroom-like odor that humans can detect at very low concentrations.

Scientists as always looking for applications for their work, often from a desire to secure further funding. There is a possibility that individuals will generate a different mix of chemicals when handling metals if they have a disease, so this work may lead to a medical diagnostic tool. Glindemann's team is looking into this.

1. Glindemann, D., et al. Angew. Chem. Int. Ed., 45 . 7006 - 7009 (2006).

November 02, 2006

US Public Concerned About Global Warming

In yesterday's post, I summarized this week's report on the economic consequences of global warming by the British Government Economic Service. The main conclusion of the report is that unchecked climate change would reduce the global gross domestic product by 5 - 20% by the beginning of the next century. Immediate limits on carbon dioxide emissions would limit this reduction to a mere 1%.

The US government has been internationally criticised for its lack of concern on global warming. Fresh on the heels of the british report are survey results that show that the US public is concerned about global warming while their government is not. The MIT Carbon Sequestration Initiative has just released results of a recent survey of public attitudes on energy and the environment. The survey, conducted in September 2006, shows that climate change has become the major environmental concern of the american public. This is a dramatic shift in public opinion from September 2003, when climate change ranked sixth out of ten environmental concerns. More than 1,200 people were surveyed in each case, but the same people were not surveyed both times.

This year, global warming was ranked by survey participants as first or second on a list of ten environmental problems. In the 2003 survey, ecosystem destruction, water pollution and toxic waste ranked higher than global warming. Nearly 75% of the survey participants stated that the government should do more about global warming. More importantly, the surveyed individuals were willing to spend their own money to help, in the form of a $21 per month increase in their electrical bill. A hundred million households contributing $21 per month amounts to $25 billion per year. This $21 extra monthly payment is far less than the current surge in home energy prices we've experienced. The US Department of Energy's Research and Development budget is just $2 billion per year. Imagine what an order of magnitude increase in the energy R&D budget would accomplish.

1. MIT Carbon Sequestration Initiative.
2. 2006 Survey of Public Attitudes on Energy and the Environment (MIT)

November 01, 2006

Global Warming Debate Heating Up

On October 30, 2006, Sir Nicholas Stern, head of Britain's Government Economic Service, released a 500-page report on the cost of climate change and the cost of efforts to reduce carbon dioxide emissions to safe levels. The main conclusion of the report is that unchecked climate change would reduce the global gross domestic product by 5 - 20% by the beginning of the next century. If steps are taken immediately to limit CO2 emissions, the affect would be a mere 1%. The study is significant because the models used are more complete than previous models, and Stern is well respected. He was once the Chief Economist of the World Bank.

According to the report, public spending on energy technologies has actually dropped in recent years. Stern says that incentives for private-sector research on low-carbon technologies should be at least doubled. The report warily sidesteps the politics of global warming, but it does recommend global adoption of European emissions trading. Emissions trading is expected to be discussed at the next meeting on the Kyoto Protocol, scheduled for 2012. The US is a signatory to the protocol, but it is a treaty that has not been ratified, and the Bush administration disavowed the Kyoto Protocol in 2001. Rapidly developing nations, such as China and India, need to pursue low-carbon technologies. Much more information on the Kyoto Protocol can be found here.

In a statement accompanying the report, Stern said that "there is still time to avoid the worst impacts of climate change, if we act now and act internationally... but the task is urgent. Delaying action, even by a decade or two, will take us into dangerous territory. We must not let this window of opportunity close."

Britain has hired Al Gore, US Vice President under Clinton and former US presidential candidate, to lobby the US government on these issues. The Bush administration prefers an emphasis on research and technology, rather than mandatory curbs, as a means to reduce CO2 emissions. Technological fixes include sequestering CO2 before it enters the atmosphere, and hydrogen-powered cars.

1. Jim Giles, "Economic review counts costs of climate change" (Nature Online, 30 October 2006)
2. Juliet Eilperin, "Warming threatens world economy, study says" (Washington Post, October 31, 2006).