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October 31, 2007

Thirtieth Anniversary

I'll be on vacation for a few days. My next article will be posted on Monday, November 5, 2007.

Today is my thirtieth anniversary with Honeywell. I joined the Materials Research Laboratory of Allied Chemical Corporation on October 31, 1977, after a post-doctoral fellowship at the University of Pittsburgh. The fellowship was endowed to honor the memory of Chaim Weizmann (1874-1952) a chemist, and the first President of Israel. Allied Chemical diversified over the years and morphed into Allied Corporation in 1981, shortly after I joined. As a result of unusual circumstances, Allied acquired Bendix Corporation in 1983, and started its involvement in Aerospace. It liked Aerospace so much (Bendix generated half of Allied's income in 1984), that it acquired the Signal Companies, another company with aerospace businesses, in 1985. The new company was named Allied-Signal. AlliedSignal (the hyphen was dropped in 1993 to emphasize a more cohesive corporate structure) acquired Honeywell in 1999, the Honeywell name was adopted [1], and here I am today with Honeywell's Aerospace Advanced Technology organization. My full curriculum vitae is available here.

Things have changed somewhat since 1977. I joined Allied Chemical to investigate magnetic bubble materials, which are now unknown beyond the few remaining specialists who worked in this area. Here's a snapshot of the technology landscape in 1977, from Wikipedia. As they say, "The past is prologue." [2]

• January 18 - Scientists identify the bacterium responsible for Legionnaires' disease.

• April 22 - First use of optical fiber to carry live telephone traffic.

• May 23 - Scientists create insulin-producing bacteria.

• May 25 - Star Wars opens in cinemas. By mere chance, I saw this movie during its premiere week in Pittsburgh.

• June 5 - The first Apple II computers go on sale.

• June 16 - Oracle Corporation was incorporated as Software Development Laboratories (SDL) by Larry Ellison, Bob Miner and Ed Oates.

June 16 - German-American rocket scientist Wernher von Braun dies. Von Braun was born in 1912.

• August 3 - The Tandy Corporation (Radio Shack) TRS-80 Model I computer is introduced.

• August 4 - U.S. President Jimmy Carter signs legislation creating the United States Department of Energy.

• August 15 - The Big Ear, a radio telescope at Ohio State University registers a signal of unkown extraterrestrial origin. This is known as the "WOW!" signal, and its origin is still unkown.

• August 20 - The Voyager 2 spacecraft is launched.

• September 3 - First sale of the Commodore PET computer.

• September 5 - The Voyager 1 is launched (somewhat after the launch of Voyager 2 on August 20).

• October 26 - The last natural smallpox case is discovered in Somalia. Smallpox is now completely erradiated through worldwide vaccination.

• October (date unknown) - The Atari 2600 game system is released.

• October 31, Devlin Gualtieri joins the Materials Research Laboratory of Allied Chemical.

• November 1 - 2060 Chiron, the first Centaurs asteroid, is discovered.

• December 1 - First flight of Lockheed's top-secret stealth aircraft project, which leads to the F-117A Nighthawk.

• December 10 - The Nobel Prizes are awarded at ceremonies in Stockholm, Sweden, and Oslo, Norway, as follow:

» Physics - Philip W. Anderson, Sir Nevill F. Mott, and John H. van Vleck ("for their fundamental theoretical investigations of the electronic structure of magnetic and disordered systems")
» Chemistry - Ilya Prigogine ("for his contributions to non-equilibrium thermodynamics")
» Physiology or medicine - Roger Guillemin, and Andrew V. Schally ("for their discoveries concerning the peptide hormone production of the brain"); and Rosalyn Yalow ("for the development of radioimmunoassays of peptide hormones")
» Literature - Vicente Aleixandre ("for a creative poetic writing which illuminates man's condition in the cosmos and in present-day society, at the same time representing the great renewal of the traditions of Spanish poetry between the wars.") [3]
» Peace - Amnesty International ("Campaign against torture")
» Economics - Bertil Ohlin, and James Edward Meade ("for their pathbreaking contribution to the theory of international trade and international capital movements")

1. Official version of Honeywell history from Honeywell web site.
2. "Whereof what's past is prologue, what to come, in yours and my discharge" William Shakespeare, The Tempest, act II, scene i, lines 253-54.
3. Forgive the editorial, but how does this in any way compare with the Physics, Chemistry, Physiology/Medicine, and Economics awards. "...Man's condition in the cosmos..." - Please! You can view some of my poetry, submitted to the 1997 American Physical Society Limerick Contest, here. So, where's my prize?

October 30, 2007

An Uphill Battle

Water is essential to life on Earth, and we have a lot of it. About 71% of Earth's surface (361 million square kilometers) is covered by a volume of water of about 1,300 million cubic kilometers [1]. Looks, however, can be deceiving, since all of Earth's water is concentrated at the surface. Although the Earth contains about 1.4 x 1021 kilograms of water, this is less than 250 ppm of its total mass. Water has many unusual properties, and new properties of water are still being discovered. I described one of these in a recent article ("Bridged by Charged Waters," October 11, 2007). But we all know that water never flows uphill, right? Well, wrong, but it flows uphil only in a few special cases.

One case, devised by a group of physicists, materials scientists and mechanical engineers from the University of Oregon, Oregon State University and the University of New South Wales, makes use of the Leidenfrost effect, first published by Johann Gottlob Leidenfrost in 1756 [2,3]. When a liquid drop is placed in contact with a surface above a critical temperature, a vapor layer is created between the surface and the liquid. This vapor layer insulates the droplet, preventing it from evaporating too quickly. The vapor layer also reduces the friction, so the droplet is especially mobile. Those of you who have worked with liquid nitrogen know that if you pour some on the lab floor (a hot surface for liquid nitrogen), the droplets scamper around the room. This effect occurs for water when the surface is above about 160oC.

The Oregon-New South Wales team was able to get water droplets to propel themselves up inclines as steep as twelve degrees. They did this by patterning the surface with saw-toothed grooves. For those of you not familiar with saw blades, saw teeth are approximately triangular in shape, but with one slope, the cutting edge, steeper than the other. The asymmetry in the sawtooth-patterned surface causes an asymmetry in the Leidenfrost vapor layer, and the vapor flows generally in one direction. The vapor carries the droplets along, like a piece of flotsam moving in a stream.

Another team, from the unlikely venue of the Department of Mathematics, University of Bristol, have published [4] results of experiments on vibration-induced climbing of droplets as another example of water flowing uphill. They placed 0.5 - 20 microliter droplets of a glycerol-water mixture on inclined Plexiglas planes with angles up to 85 degrees. These one to three millimeter diameter drops were sessile drops; that is, they remained stationary because of surface tension. Anyone who has shaken rain water droplets from an umbrella or coat sleeve knows that shaking loosens water drops, so it seems likely that shaking would have loosened the droplets on the inclined plane and allowed them to slide downhill. However, when the research team vibrated the plane in a vertical direction between 30 and 200 Hz, they found that above a certain vibration amplitude the droplets move uphill. Further investigation showed that that this behavior is caused by deformation of the contact angle of the droplet, which causes the droplet to be propelled in one direction by surface tension effects. The advancing contact angle of the propelled droplets was found to be nearly twice as large as the receding contact angle. The Bristol team thinks there may be application of this effect in microfluidic devices.

1. Ocean (Wikipedia)
2. Roland Pease, "Scientists make water run uphill" (BBC News).
3. H. Linke, B. J. Alemán, L. D. Melling, M. J. Taormina, M. J. Francis, C. C. Dow-Hygelund, V. Narayanan, R. P. Taylor, and A. Stout, "Self-Propelled Leidenfrost Droplets," Phys. Rev. Lett., vol. 96, 154502 (2006).
4. P. Brunet, J. Eggers, and R. D. Deegan, "Vibration-Induced Climbing of Drops," Phys. Rev. Lett. 99, 144501 (2007).

October 29, 2007

Turing Machines

One achievement of Alan Turing, who is considered to be one of the founders of the field of computer science, is the concept of a simple computing machine now called a "Turing Machine." [1] The remarkable thing is that this concept of a computer was devised in 1936, long before physical digital computers were common. The first electronic digital computer is considered to be the Atanasoff-Berry computer, which was designed in 1937. The Atanasoff-Berry computer worked somewhat, but its development was abandoned in 1942. Turing used his virtual machine as a vehicle for proof of a mathematical problem known at the time as the Entscheidungsproblem, but is now known as the Halting Problem. The Halting problem is essentially this - If you have a computer program and all (finite) input parameters to that program, is it possible to determine whether your computation will end? Turing's paper on the topic was published in 1937, and it showed that it is not possible to determine whether a computation on a Turing Machine will end. This proof is not just limited to a Turing Machine, since Turing proved that certain Turing Machines (Universal Turing Machines) can simulate any practical computing model, albeit very slowly.

A Turing Machine is constructed from a tape, movable forward and backwards; a read-write head; a state table that knows whether the tape has been moving forwards or backwards, and the last symbol(s) read; and an action table that decides what the machine should do based on the symbol under the read head and the state table. Of course, it doesn't matter whether the tape is a paper tape, or a magnetic tape, etc.; and the corresponding read-write head can be some sort of pen, or a magnetic head, or anything else that works with the particular tape.

Computer scientist and entrepreneur Stephen Wolfram, who received a physics Ph.D. at age twenty, has a current interest in Turing Machines. Wolfram developed the symbolic computation language Mathematica, which has earned him a small fortune (If you know the price of Mathematica, you know why. It's still a wonderful program). As a result of his wealth, Wolfram has been able to devote significant time to research in computation and mathematics. His main interest is cellular automata, and these figure prominently in his book, "A New Kind of Science," now freely available online [2]. In this book, Wolfram found the simplest known Universal Turing Machine, one with two states and five symbols. It's known that Turing Machines of two states and two symbols are not universal, so Wolfram became interested in whether a Turing Machine of two states and three symbols could be universal. He investigated all 2,985,984 of these, and he selected one of these he felt was the most likely candidate. The rules for this machine [3] are as follow:

{state, symbol} -> {state, symbol, offset}
• {1, 2} -> {1, 1, -1}
• {1, 1} -> {1, 2, -1}
• {1, 0} -> {2, 1, 1}
• {2, 2} -> {1, 0, 1}
• {2, 1} -> {2, 2, 1}
• {2, 0} -> {1, 2, -1}}

This Turing Machine has no halt state, and it operates on a tape of infinite length.

A $25,000 prize was posted for a proof of the universality (or non-universality) of this machine, and it was won just 47 days later by twenty year old Alex Smith, an electrical engineering undergraduate from the University of Birmingham with an interest in computer science. [4-7] Yes, mathematics is a young person's game. Smith must be doing his homework, since he proved his theorem using a traditional mathematics method; namely, showing that the problem is equivalent to another that's already been solved. Smith's forty-page proof will be published in a future issue of Complex Systems, a journal founded in 1987 by Stephen Wolfram.

I don't know whether it's the "sour grapes" effect, but a prominent computer scientist is quoted as saying, "Most theoretical computer scientists don't particularly care about finding the smallest universal Turing machines... They see it as a recreational pursuit that interested people in the 60s and 70s but is now sort of 'retro'."[5] This may be more of a reaction against Wolfram, rather than Smith, since Wolfram is seen by many as being excessively self-promoting. An award ceremony is planned at the site of much of Turing's computer work, Bletchley Park.

1. What is a Turing Machine? (Wolfram Science).
2. Stephen Wolfram, "A New Kind of Science," Wolfram Media, Inc., May 14, 2002. ISBN 1-57955-008-8
3. The Rules for the Machine (Wolfram Science)
4. Jim Giles, "Simplest 'universal computer' wins student $25,000" (New Scientist News, October 24, 2007).
5. Geoff Brumfiel, "Student snags maths prize" (Nature News, October 24, 2007).
6. Prize Announced for Determining the Boundaries of Turing Machine Computation (Wolfram Science).
7. Wolfram's 2,3 Turing Machine Is Universal! (Wolfram Science Press Release).

October 26, 2007

Hum a Few Bars

There's an old joke about a musician playing a piano at a party. One of the guests walks up to him and says, "Do you know our host has a headache and needs some quiet?" The musician says, "No, but hum a few bars and I'll fake it!" Apparently, this joke doesn't translate well into other languages, since only English has this ambiguous verb "to know" that can mean more than one thing. Then there's there, their, and they're - but we digress.

The Earth has been humming. Some people think they know why, but other people believe that it's humming more than a single tune. One hum, well below the threshold of human hearing, is at an incredibly low frequency, about a hundredth of a hertz [1, 2]. For reference, this is about fifteen octaves below middle C, 261.6 hertz, which is technically called C4. This hum, first detected by Japanese scientists in 1998, was thought to be caused by atmospheric turbulence vibrating the ground. Over the last few years, scientists at the University of California at Berkeley and Columbia University found that the amplitude of the hum was correlated with ocean storms along the coastline, but the mechanism of how such storms could cause the hum was unclear. Spahr Webb of Columbia University's Lamont Doherty Earth Observatory determined that the hum is caused by counter-propagating waves that give rise to a long wavelength standing wave exciting the ocean floor [3].

Another hum, called "The Hum," or the "Taos Hum" from one of its focal points, is an enigmatic low frequency hum audible to some humans. In most cases, it can't be detected by microphones, and there are theories that it may be an electromagnetic phenomenon acting directly on the brain. Conjectured sources include pulsed microwave radar, or electromagnetic emissions from meteors. Large meteors, when they disintegrate in Earth's atmosphere, are known to emit many megawatts of audio frequency power. The constant steam of smaller meteors may generate a background hum in the atmosphere. Of course, every mystery has a conspiracy component. In this case, it's the extremely low frequency (ELF) radio transmissions used to communicate with submarines, or the High Frequency Active Auroral Research Program (HAARP). HAARP, funded by the US military, injects intense radio waves into the ionosphere. The cause could be merely tinnitus.

1. Catherine Brahic, "Earth's hum linked to coastal waves" (New Scientist, 15 February 2007).
2. Jenny Hogan, "Earth's 'hum' springs from stormy seas" (New Scientist, 29 September 2004)
3. Spahr C. Webb, "The Earth's 'hum' is driven by ocean waves over the continental shelves," Nature, vol. 445 (15 February 2007), pp. 754-756.
4. The Hum (Wikipedia).

October 25, 2007


They say that money can't buy happiness. I don't think this has ever been tested experimentally, so if someone gives me several million dollars, I'd be happy to do some research. Scientists are people, too, so it's no wonder that they think about things such as happiness; specifically, how one could quantify happiness.

Wilhelm Ostwald (1853-1932) was a German chemist who received the Nobel Prize in Chemistry in 1909. Ostwald is well known among chemists for the Ostwald process for the synthesis of nitric acid; and among metallurgists and other materials scientists for Ostwald ripening, which I reviewed in a previous article. He is considered to be one of the founders of the field of physical chemistry. In 1905, Ostwald published his equation for happiness [1-2]

G = (E + W)(E - W)

in which E is the energy expended on things we want to do, and W is the energy expended on things we don't want to do. Although Ostwald's formula does give the interesting boundary conditions that happiness is E2 when you are doing only what you want to do, and -W2 when you are doing everything you don't want to do, a physicist's model would be different. My own model is this

G = (E - W)/(E + W)

In this case, I assume that energy is conserved ( E + W = constant), and you get +1 if you're perfectly happy, and -1 if you're completely unhappy. Most of us are likely near the G = 0 point.

There is statistical evidence [3] that money can buy some measure of happiness. Wealthy countries that have considerable healthcare spending, as does the US, have a higher proportion of citizens who consider themselves happy. In effect, capitalism makes you happier.

1. Gary B. Ferngren, "Science and Religion: A Historical Introduction," JHU Press (2002, ISBN 0801870380), pp. 305f.
2. Gerald Holton on Ostwald's Happiness Equation.
3. Roxanne Khamsi, "Wealthy nations hold the keys to happiness" (New Scientist Online, July 28, 2006).

October 24, 2007

Doing It by the Numbers

My father, who was a building contractor, often would use the phrase, "Doing it by the numbers." Whenever he had a large, daunting task, he would break it down into a numbered list of small sequential tasks that didn't seem that hard to do. His usual task was building a house, so his list would start with surveying the lot, excavating for the foundation, digging the trenches for the utility pipes, etc. Each numbered task would take about a day or two, and at the end of the list you have a house. Nowadays, I do the same thing with Microsoft Project, although my research tasks are quite a bit more nebulous than production tasks. As US President Dwight Eisenhower once said, "Plans are useless, but planning is indispensable." [1]

Mathematicians have their own way of "doing it by the numbers." They attempt to do things with "economy, surprise and fecundity" [2], and this approach to problem solving is highlighted in a recent book by Béla Bollobás, "The Art of Mathematics: Coffee Time in Memphis". [3] Bollobás is a professor at the University of Memphis who organizes a yearly conference in honor of the famous mathematician, Paul Erdös. The book is a collection of easily stated problems that offer an opportunity for elegant solutions in the tradition of Erdös. One interesting example, as restated in a review of this book [2] by James Propp, a professor of mathematics at the University of Massachusetts at Lowell, is as follows:

"Suppose 10 chairs are arranged in a circle, half of them occupied by students. Show that there exists some whole number n between 1 and 9 such that if each of the 5 students moves n chairs clockwise in the circle, 3 or more of them will end up sitting in a previously occupied chair."

As a computer programmer, I see that this is an easily programmed problem. Since there are just a few possible cases, I could check every combination. However, since I only need a "yes" or "no" answer, I would write a shorter program to randomly populate the chairs, randomly rotate the students, check the result, and do this a million or more times, or until a solution is found. The elegant mathematical solution uses randomness, also, but it's done in far less time than my writing a program. If the rotation index n is random, then each student has a 4/9 chance of sitting in a previously occupied chair. Since there are five students, then the average chance is just 4/9 + 4/9 + 4/9 + 4/9 + 4/9 = 20/9. Now, this is a little more than two, and the only way we can get an average greater than two is if one of the results that's averaged is at least three. This solution exhibits economy and surprise. Propp further suggests that it exhibits fecundity, since this method is general enough to be applied to other problems.

This is one of the simpler problems, and Propp recommends the book only to actual or budding mathematicians. There are just thirteen problems, such as the one above, that involve arithmetic; and there are a hundred more involving more advanced mathematics.

1. As quoted by Richard Nixon in "Six Crises" (Doubleday, 1962).
2. James Propp, "Theorems to Savor," American Scientist, vol. 95, no. 9 (November-December 2007), pp. 536-8.
3. Béla Bollobás, "The Art of Mathematics: Coffee Time in Memphis (Paperback)," Cambridge University Press, 2006 (ISBN-10: 0521693950, ISBN-13: 978-0521693950, via Amazon.com)

October 23, 2007

Carbon Nanotube Radio?

In a previous article I discussed the assessment by materials scientist Stephen J. Pearton that nanomaterials were being over-sold. Pearton writes that nanotechnology is at the "overhype stage," and it is ripe for a backlash in the next few years. An article [1] scheduled to appear soon in Nano Letters is a good example of this. The article, by Chris Rutherglen and Peter Burke of the Department of Electrical Engineering and Computer Science at the University of California, Irvine, is entitled "Carbon Nanotube Radio." The title, however, is misleading, since what's presented is just an imperfect rectifier diode coaxed to produce a very inefficient amplitude demodulator, and it acts as a radio signal demodulator with much peripheral equipment. Nonetheless, the result is being presented as a significant breakthrough [2].

The Irvive researchers synthesized carbon nanotubes on high resistivity (> 8000 Ohm-cm) silicon wafers using common CVD techniques with iron as a catalyst. In this case, the silicon was just a convenient substrate, and it was not used as an electronic material. After the carbon nanotubes (CNTs) were formed, a multitude of Pd-Au electrodes were evaporated with a 50 micrometer gap, and the electrode pairs found to be bridged by a single carbon nanotube were selected for study. The published current-voltage curve is nearly linear, which resembles a resistor, rather than a diode, but there is enough non-linearity for the assembly to function as a Schottky diode (metal-semiconductor junction diode) when the electrodes are biased at a certain voltage. Demodulation action was confirmed with a laboratory radio frequency generator, and then an antenna was attached to form a primitive radio. A 1 GHz signal generator with attached antenna was used as a transmitter modulated by an iPod. The detector signal was sent to an amplifier, where "The audio-quality of the signal demodulated by the CNT was very clear and indistinguishable to the human ear from listening to the music directly." Radio reception was possible over a one meter range. The Irvive research was supported by the Army Research Office and the Office of Naval Research. Perhaps with a little more money, they can produce the local oscillator, RF amplifier, mixer, intermediate-frequency amplifier, and audio amplifier required to demonstrate a real radio.

1. Chris Rutherglen and Peter Burke, "Carbon Nanotube Radio," Nano Letters (ASAP Article 10.1021/nl0714839 S1530-6984(07)01483-X, to be published in November 14, 2007, issue).
2. Alexis Madriga, "Scientist Broadcasts Music to Nano Radio Using iPod Transmitter" (Wired News, October 17, 2007).

October 22, 2007

The Solar Decathlon

Winners were announced recently in the Solar Decathlon, a competition for teams of college and university students to design, construct and operate an energy-efficient solar-powered house. The Solar Decathlon is sponsored by the Office of Energy Efficiency and Renewable Energy of the US Department of Energy, and Honeywell is a supporting sponsor. Honeywell supplied its Enovate blowing agent for foam insulation, as well as programmable thermostats and other building control components. As one who received many team tee-shirts from Honeywell over the years, I was not surprised to find that Honeywell provided shirts and jackets to the organizers, volunteers, students, and the other personnel who showcased the twenty finalist homes at an exhibition at the National Mall, Washington, D.C., October 12 - 20.

The contest requirements included the stipulations that the home must be completely solar-powered and include charging power for an electric vehicle. A major portion of this venture was transport of the homes to the National Mall. This was almost a show-stopper for one team, Santa Clara University, whose transport truck broke an axle on the way to the competition. The Team scores and the winners were announced Friday, October 19. First place was awarded to the Technische Universität Darmstadt, which was judged to have an exceptionally engineered photovoltaic system - enough to get a perfect score in that category. Second place went to the University of Maryland, which was praised for its web site. One glance at the team photograph on this site will show the effort that went into this contest. Third place went to Santa Clara University, plagued by the broken axle, but undeterred. Rounding out the top ten (in rank order) were Penn State, the Universidad Politécnica de Madrid, the Georgia Institute of Technology, the University of Colorado at Boulder, Team Montréal (École de Technologie Supérieure-Université de Montréal-McGill University), the University of Illinois at Urbana-Champaign, and the University of Texas at Austin. Team scores can be found at the contest web site [1].

1. Solar Decathlon Web Site.

October 19, 2007

The Bell Curve

When a Nobel Laureate speaks, everyone listens, so when James Watson, co-discoverer of the structure of DNA, and winner of the 1962 Nobel Prize in Physiology or Medicine, commented recently [1-4] that test results indicate that people of African descent are not as intelligent as white people, he made headlines all over the world. In this remark, he follows in the tradition of another Nobel Laureate, William Shockley. Schockley shared the 1956 Nobel Prize in Physics for the invention of the transistor. In his later years, he was an advocate of eugenics, and many of his views were considered racist. There is a theory that Schockley's unusual behavior may have been the result of a brain injury from an automobile accident, as I wrote in a previous article.

All this calls to mind the controversy engendered in 1994 by the publication of the book [5], "The Bell Curve," by Richard Herrnstein of Harvard University and Charles Murray of the American Enterprise Institute, a conservative "Think Tank." The book's premise is that intelligence is a better predictor of success than things such as education and social background. A portion of this book discussed differences in race and intelligence, and the authors were misrepresented in the popular press as supporting a genetic link between race and IQ. When the press heard something similar from Watson, who discovered the scientific basis for genetics, it was too good of a story to pass up. Cold Spring Harbor Laboratory, Watson's current employer, was quick to issue a statement: [6]

"The board of trustees, administration and faculty vehemently disagree with these statements and are bewildered and saddened if he indeed made such comments... Cold Spring Harbor Laboratory does not engage in any research that could even form the basis of the statements attributed to Dr. Watson."

1. Alexis Madrigal, "Watson Rediscovers 1940s Attitudes Towards Race' (Wired News, October 17, 2007).
2. Museum drops race row scientist (BBC News, October 18, 2007).
3. Zachary R. Dowdy, "Nobel researcher slammed for racist statement" (Chicago Tribune, October 18, 2007).
4. Lucy Sherriff, "Museum drops Watson talk in race row" (The Register, October 18, 2007).
5. Richard Herrnstein and Charles Murray, "The Bell Curve," Free Press, 1994 (ISBN 0-02-914673-9, via Amazon.com).
6. Statement by Cold Spring Harbor Laboratory Board of Trustees and President Bruce Stillman, Ph.D. Regarding Dr. Watson's Comments in The Sunday Times on October 14, 2007.

October 18, 2007


Sometimes, a published commentary is so true, I wish I had written it. A recent example is a commentary on the practice of science by Stephen J. Pearton published in a recent issue of Materials Today [1]. Pearton is a Distinguished Professor in the Department of Materials Science and Engineering at the University of Florida. Before joining the University of Florida in 1994, he was a Member of the Technical Staff at Bell Labs for ten years, so he has a perspective on the practice of both academic and industrial research. Pearton observes that there's a lot of hype in the nanotechnology area. In the past, the emphasis in materials science was on creating perfect materials, such as single crystals without dislocations (e.g., silicon for electronics), or continuous epitaxial layers of controlled thickness (e.g., for semiconductor lasers). Now, the "crud" that collects on the sides of the same reactor vessels used in the past to make perfect materials is being collected, photographed, and presented as marvels of nanotechnology.

Pearton lists the following as stages in a technology cycle.

• Pre-buzz
• Buzz
• Rave-Reviews
• Saturation
• Overhype
• Backlash
• Backlash-to-the-Backlash

Pearton positions nanotechnology at the overhype stage, ripe for a backlash in the next few years. Spintronics is at about the same stage, since its promised benefits in faster computer circuits have not materialized in tangible products. High temperature superconductivity was oversold in the late 1980s and early 1990s, but some significantly successful power transmission line demonstrations have boosted the field of applied superconductivity into the backlash-to-the-backlash stage. Multifunctional materials are at the pre-buzz phase, organic electronics (especially organic light-emitting diodes) has entered the rave-reviews phase, and biomaterials are at the saturation phase, just about to enter the overhype phase.

The winners in the materials technology cycle are high temperature alloys, which have been around long enough to have weathered the early phase and establish themselves in the backlash-to-the-backlash phase. The backlash-to-the-backlash phase could be renamed the "I told you so" phase. Solar energy is of the same demographic as high temperature alloys, having weathered the many misfortunes of the technology cycle to finally reach the backlash-to-the-backlash phase. What's a scientist to do? As I read it, pre-buzz and buzz phases (DARPA theme projects) are great, but devote at least some effort to the mature areas that constitute the "I told you so" phase. The over-hyped and backlash areas should be avoided at all cost.

1. Steve Pearton, "The shifting tide of expectations," Materials Today, vol. 10, no. 10 (October 2007), p. 6.

October 17, 2007

Physics Fights Fat

Impedance Spectroscopy, sometimes called Dielectric Spectroscopy, is a method of material characterization through measurement of the electrical impedance at different frequencies; in particular, the phase and amplitude relationship between applied voltage and the resultant current. This allows calculation of the real and imaginary parts of the permittivity. Frequency in this case can range anywhere from sub-audio range (millihertz) through optical (1015 Hz) [1]. The material response at certain frequencies indicates the time scale of either a resonance or a relaxation process, and this gives information about various molecular properties or the composition of materials. For example, radio frequencies are used to determine the quantity of water in polymer materials and food grains. Now, it's possible to buy an inexpensive body fat meter based on impedance spectroscopy.

The Omron Model HBF-306 Personal Body Fat Meter is available at many drug stores for $30-$50 [2]. The unit resembles a game controller with two handles, held for the measurement, and a central electronics pod. The electrical equivalent circuit of the human body, measured hand-to-hand, will resemble a parallel combination of a resistor and a capacitor. The HBF-306 uses a fixed frequency (50 kHz) constant current source of 500 microamps, and the resultant voltage signal is used for the measurement. Since resistance will depend on electrolyte content, and fat is devoid of electrolyte, you can see how this would work. Of course, humans are variable in more than just percentage of fat, so you need to enter sex, height, weight and age before measurement, and Omron has accumulated clinical data to give acceptably accurate measurements for different types of people. A particular stance must be used during measurement, with arms extended forward, and feet slightly spread. All this is to prevent "short circuits" in the conductance path. Furthermore, body impedance varies throughout the day, so the test should be done at a specific time of day.

At this point, I lost interest in purchasing this meter, and it seems that if you add a few more variables to sex, height, weight and age, such as wrist girth (for bone mass), waistline (for obvious reasons), and "pinch" thickness (the "pinch-an-inch" concept), you can calculate percentage body fat without this device. However, you may be able to modify this device for some sort of measurement in the laboratory, and you won't need to fill-out endless forms for procurement of a capital item. Omron has been working on the idea of a body fat meter for many years [3]. If you examine the "referenced by" list to their 1996 patent, you can see that many others have been working on the same idea.

1. Graph of the frequency response of various dielectric mechanisms in terms of the real and imaginary parts of the permittivity (Wikipedia Image).
2. David Carey, "Body fat meter is thinly priced" (EE Times, October 8, 2007, page 30).
3. Yoshihisa Masuo, "Device to provide data as a guide to health management," US Patent 5,579,782, Issued December 3, 1996 (via Google Patents).

October 16, 2007

The Allen Array

Does intelligent life exist elsewhere in the universe? This is an important question, and it's one that was finally open to scientific study about fifty years ago with the construction of sensitive radio telescopes. We have the ability to receive radio transmissions from other civilizations, whether they beam them intentionally to Earth, or we eavesdrop on their routine communications. Of course, there are a few problems with this idea. What frequency should we monitor? There's the idea that we should look around the "water hole," the quiet place in the galactic noise spectrum (from 1.42 GHz to 1.64 GHz) between a hydrogen radio emission line and the strongest hydroxyl spectral line. This is still a lot of bandwidth to cover, and there's a possibility that advanced civilizations may have gone beyond simple radio to some advanced communications technology; or, perhaps, they are not interested in communication with someone else.

The first search for extraterrestrial radio signals was done in 1960 by Frank Drake, an astronomer at Cornell University. Drake used the National Radio Astronomy Observatory telescope at Green Bank, West Virginia, to observe the nearby stars, Tau Ceti and Epsilon Eridani, but nothing was discovered. This observation project, called Project Ozma, was followed by a few other observations, but the US government decided to withhold further financial support in the search for extraterrestrial intelligence, and the field languished. However, there was enough interest among the general population to fund the SETI Institute, founded in 1984 to keep SETI research alive. This is fortunate, since advances in computer and communications technology have provided an enhanced opportunity for detection of SETI signals.

The SETI Institute has been conducting observations by piggy-backing equipment onto operating telescopes in a way as to not affect the primary observations. The problem is that they have no choice of where to look, or for how long, since direction of the telescope is out of their control. This problem has now been solved through the largesse of Paul Allen, co-founder of Microsoft, and someone rich enough to build a radio telescope. The eponymous Allen Array, an array of dish antennas, twenty feet in diameter, working in concert to simulate a huge dish antenna, was commissioned on October 11, 2007 [1-3]. At this time, there are just a forty-two of its antennas in place, but it will eventually have 350. Allen, who became interested in SETI after conversations with Carl Sagan many years ago, provided an initial $25 million to fund the telescope in 2001, but other public support will be required to finish it. To date, about $50 million has been spent on construction, with additional support coming from UC Berkeley, the SETI Institute, the National Science Foundation, Xilinx, Nathan Myhrvold (a Microsoft Alumnus), Greg Papadopoulos (CTO of Sun Microsystems), and other corporations and individuals.

Management of the Allen Array is done jointly by the SETI Institute and the Radio Astronomy Laboratory of the University of California, Berkeley. It is estimated that it will take another forty million dollars to complete the Allen Array, bringing the total cost very close to $100 million. The Allen Array could be built for just $100 million, since it uses COTS (Commercial-Off-The-Shelf) technology. This includes communications components developed for satellite television, and advanced digital signal processing chips (thus the Xilinx connection). An important consideration is the ability to filter-out man-made interference. The full array of 350 antennas will be able to detect signals from as far away as 500 light years if they are transmitted directly at the Earth using the same communications equipment we Earthlings have available. This is the 1,000-foot-diameter Arecibo Observatory in Puerto Rico, which has the ability to transmit as well as receive. This volume of space encompasses about a million stars.

As for the idea that extraterrestrials may have advanced beyond radio, perhaps there are some extraterrestrial hobbyists out there who enjoy tinkering with steam engine technology and transmit just for the fun of it.

1. Dennis Overbye, "Stretching the Search for Signs of Life" (New York Times, October 11, 2007).
2. Anil Ananthaswamy, "New radio telescope begins search for alien signals" (New Scientist, October 11, 2007).
3. Robert Sanders, "Radio telescope array dedicated to astronomy, SETI" (UC Berkeley Press Release, October 11, 2007).

October 15, 2007

Nobel Prize in Chemistry

In a previous article, I summarized the work done by Albert Fert and Peter Grünberg, who were awarded the 2007 Nobel Prize in Physics. Since materials science is a mixture of physics, chemistry and engineering, it's only fair that I review the Nobel Prize in Chemistry, also. Unfortunately, there is no explicit Nobel Prize for engineering, although some engineering topics creep into the physics and chemistry awards.

Gerhard Ertl, an emeritus professor at the Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, has been awarded the 2007 Nobel Prize in Chemistry for his work on heterogeneous catalysis. Ertl's major contribution was elucidating the molecular processes involved in the synthesis of ammonia from hydrogen and nitrogen on an iron catalyst, the Haber process, but he did research in many other areas of catalysis, including the oxidation of carbon monoxide by platinum and palladium catalysts. In his research, he took full advantage of the new technological tools for surface analysis, such as low energy electron diffraction and scanning tunneling microscopy. Ultra-high vacuum technology was important, also. Ertl's research has helped the development of material surfaces that impede reactions, such as oxidation of materials themselves. As sole recipient of the award, Ertl gets a cash award of $1.5 million.

What a catalyst does is increase the rate of a reaction that is energetically favored and should proceed, but it is impeded by an energy barrier. In the Haber process, nitrogen and hydrogen are reacted over an iron catalyst to produce ammonia. Ammonia is an essential reagent in the production of nitrates for such things as fertilizer and explosives. Fritz Haber and Carl Bosch were awarded separate Nobel Prizes for this process. The main problem for this reaction is that nitrogen gas consists of triply-bonded nitrogen atoms, so nitrogen relatively inert. However, its reaction with hydrogen is energetically favored, having an exothermic enthalpy of reaction

N2(g) + 3H2(g) -> 2NH3(g)

The process, developed by Haber and Bosch, uses an iron catalyst with a pinch of alumina (Al2O3) and potassium oxide (K2O) as promoters. The reaction proceeds at 250 atmospheres pressure and 450-500 oC with a yield of about 15% and a reaction enthalpy of -92.4 kJ/mol.

The reaction mechanism, as elucidated by Ertl, is as follows:

• N2(g) -> N2(adsorbed)
• N2(adsorbed) -> 2N(adsorbed)
• H2(g) -> H2(adsorbed)
• H2(adsorbed) -> 2H(adsorbed)
• N(adsorbed) + H(adsorbed) -> NH(adsorbed)
• NH(adsorbed) + H(adsorbed) -> NH2(adsorbed)
• NH2(adsorbed) + H(adsorbed) -> NH3(adsorbed)
• NH3(adsorbed) -> NH3(g)

The reaction N2(adsorbed) -> 2N(adsorbed) is the rate-limiting step.

Ertl said at a press conference that when he heard that a German (Peter Grünberg) had won the 2007 Nobel Prize in Physics, he thought it unlikely that another German would win the chemistry prize, so he put the idea out of his mind. A Nobel Prize had not been awarded for surface science since 1932, when Irving Langmuir won the chemistry prize for his "work in surface chemistry."

1. John Schwartz, "Nobel in Chemistry Honors Expert on Surface Encounters" (New York Times, October 11, 2007).
2. Rick Weiss, "Chemist Wins Nobel For Catalyst Studies" (Washington Post, October 11, 2007).
3. Bethany Halford, "Nobel Prize in Chemistry" (Chemical & Engineering News, October 10, 2007).

October 12, 2007


Seamen have a long tradition of knot tying, and there's a specific knot for every major shipboard task. Knots can be a nuisance also, as young girls with long hair are quick to discover. Although mathematicians have developed the idea of the knot into a mathematical object, there hasn't been much research into knots as physical objects. Of course, physicists are known for investigating commonplace things and finding unusual properties, so it was only a matter of time that spontaneous formation of knots (tangles) would be researched.

Dorian Raymer and Douglas Smith, two physicists from the University of California at San Diego have published the results of experiments on the spontaneous formation of knots in a piece of string in a current issue of the Proceedings of the National Academy of Sciences [1, 2]. Their experiment was extremely simple, although the analysis of the data was fairly complex and involved mathematical concepts such as the Jones polynomial. They dropped a string into a box that was tumbled at about one revolution per second for ten seconds, and they repeated this for 3,415 trials. During the course of their trials, they varied the length of the string, the stiffness of the string, the size of the box, and the tumbling rate.

Short strings (less than about 18 inches) did not form knots. The probability of knotting increased sharply between 18 inches and five feet, but it leveled-off at five feet. The highest probability of knotting was for a long, flexible string in a large box. A small box limits the possible motion of the string. They observed 120 different types of knots, and they generated every type of knot with up to seven crossings in their 3,415 trials. Raymer developed a model of knotting that matched their observations. The string forms concentric loops when dropped into the box, and rotation allows the free ends to weave through the loops. There is a 50% probability that the end will cross over or under a loop and then travel to the left or right.

Surprisingly, despite the ubiquity of knots in daily life, there is only one major myth involving a knot (OK - perhaps String Theory qualifies as a new modern myth). That's the Gordian Knot, a knot supposedly impossible to untie. There was a prophesy that the person who could untie the knot would become the king of Asia Minor. In 333 BC, Alexander of Macedonia (a.k.a., Alexander the Great) "untied" the knot by slicing it with his sword, although other accounts have him sliding the knot off the post to which it was tied. In any case, Alexander did conquer Asia Minor.

1. Jeanna Bryner, "The Science of Knots Unraveled" (LiveScience, October 3, 2007).
2. Dorian M. Raymer and Douglas E. Smith, "Spontaneous knotting of an agitated string," Proc. Natl. Acad. Sci. USA (published online October 2, 2007).

October 11, 2007

Bridged by Charged Waters

Water is an important substance. It's the "universal solvent" and it has many unusual properties. As for electrical properties, pure water is an excellent insulator, and the resistivity of water is often used as an indicator of its purity. In the real world, water is full of electrolyte impurities, and that's the reason why it's generally a conductor. Water has an extremely large dielectric constant of about 80, so it has a large influence on radio waves, particularly in transmission lines. Dry nitrogen is often pumped into high power transmission lines to exclude water vapor.

Water keeps surprising us with new effects, the most recent of which is being studied by scientists at the Graz University of Technology, Austria, although they credit the initial discovery to Wolfram Uhlig of the Laboratory of Inorganic Chemistry, the Swiss Federal Institute of Technology, Zürich. When a high voltage (15 kV) is applied to triply-deionized water (18 megohm-cm resistance) within contacting 6 cm diameter, 100 mL beakers to 3 mm below the edge, a water bridge forms spontaneously between the beakers [1]. Water climbs out of the beakers, crosses empty space, and joins to form a bridge. The bridge is cylindrical in shape, has a diameter of a few millimeters, and it remains intact when the beakers are separated by up to an inch.

Measurements indicate that water is usually transported from the anode (positive supply) beaker to the cathode (negative supply) beaker, but the direction of mass transport varies and could not be predicted. Addition of even the smallest amount of electrolyte to the water destroyed the bridge. The Graz team used high speed photography to discover the existence of high frequency mechanical oscillations inside the water bridge which they attribute to noise in their power supply. Since a small current flowed through the water, it eventually heated to about 60 oC in 45 minutes, at which time the bridge collapsed. Their current theory on why these bridges form is that they are produced by the "cone-jet" effect described in previous research [3-5]. The principal action in this case is a result of the high dielectric constant of water, which concentrates the electric field within the bridge to order the water molecules into a mechanically stable microstructure. It would be interesting to see whether this effect can be made useful in some device.

While writing about water bridges, I would be remiss if I didn't mention a popular recording from my college years; namely, Bridge over Troubled Water, released in 1970 by Simon and Garfunkel. This was the duo's fifth and final studio recording, selling 25 million copies to date. It's been ranked among the hundred best record albums by both Rolling Stone magazine and the VH1 television network.

1. Lisa Zyga, "Water forms floating 'bridge' when exposed to high voltage" (PhysicsOrg).
2. Elmar C. Fuchs, Jakob Woisetschläger, Karl Gatterer, Eugen Maier, René Pecnik, Gert Holler, and Helmut Eisenkölbl, "The floating water bridge," J. Phys. D: Appl. Phys. 40 (September 21, 2007) 6112-6114.
3. R.P.A. Hartman, D.J. Brunner, D.M.A. Camelot, J.C.M. Marijnissen and B. Scarlett, J. Aerosol Sci., vol. 31, pp. 65-95 (2000).
4. R.P.A. Hartman, D.J. Brunner, D.M.A. Camelot, J.C.M. Marijnissen and B. Scarlett, J. Aerosol Sci., vol. 30, pp. 823-49 (1999).
5. R.P.A. Hartman, J-P Borra, D.J. Brunner, J.C.M. Marijnissen and B. Scarlett, J. Electrostat., vol. 47, pp. 143-70 (1999).

October 10, 2007

And the Winner is...

The 2007 Nobel Prize in Physics has been awarded to Albert Fert and Peter Grünberg "for the discovery of Giant Magnetoresistance." [1-7] This is the ninth time that the Nobel Prize has been given explicitly for work involving magnetism since it was first awarded in 1901; or ten times if you include work for which magnetism is essential, such as that of Charles Guillaume. Guillaume discovered how magnetism can be used to create alloys, such as Invar, with a zero coefficient of thermal expansion.

Albert Fert (1938-) is a French physicist and professor at the Université Paris-Sud. Peter Grünberg (1939-) is a German physicist who retired in 2004 from the Jülich Research Centre. Fert and Grünberg independently discovered giant magnetoresistance (GMR) in 1988. Many materials demonstrate the magnetoresistance effect, discovered by William Thomson (a.k.a., Lord Kelvin - Yes, that Kelvin). This is a small change in electrical resistance (up to a few percent maximum) with applied magnetic field. Nowadays, this is known as the "ordinary" magnetoresistive effect, since GMR devices achieve an order of magnitude greater change, and "colossal magnetoresistance" offers an order of magnitude greater than even this. However, most "colossal" devices exhibit very large temperature changes in resistance, so they are not that useful.

Magnetic disk storage devices for computers have typically used magnetoresistive heads to read the magnetic data, but the ordinary magnetoresistive effect constrained the data density to such an extent that early magnetic disk drives were the size of a refrigerator. Giant magnetoresistive heads launched the high density disk drive revolution to give us the large capacity hard drives in our personal computers, and the extremely small disk drives in some portable music players. Fert and Grünberg realized that since both magnetism and electrical conductivity were competing functions of electrons in materials, a specific device structure might allow an easier transition from one state to another, thereby increasing the magnetoresistive effect. The (by now) obvious choice was a sandwich of magnetic and non-magnetic, but electrically conductive, materials of nanometer dimensions. The actual physical effect involves electron spins, and GMR opened up a new field of "spintronics," a magnetic variant of electronics. It took about ten years for GMR to transition from the laboratory to a product, since the first disk drive with a GMR read head was introduced in 1997. Current projections indicate that a magnetic data density of 1,000 gigabit-per-square-inch is attainable. Since disk drives contain multiple two-sided platters, this is a lot of data per cubic inch.

Fert and Grünberg will share a $1.5 million cash prize. This sounds like a lot of money, but for calibration purposes, I'll list the 2007 salaries of three New York Yankees Baseball Players. The Yankees were eliminated from the Eastern Division American League play-offs on Monday (10/8/2007).

• Alex Rodriguez - $27,708,525
• Jason Giambi - $23,428,571
• Derek Jeter - $21,600,000

"Baseball has been very good to me." [8]

1. Nobel Foundation Press Release, October 9, 2007.
2. Matt Moore and Karl Ritter, "Physics Nobel goes to German, Frenchman" (Yahoo News, October 9, 2007).
3. Zeeya Merali, "Hard-disk breakthrough wins Nobel Prize" (New Scientist News, October 9, 2007).
4. French, German Scientists Win Nobel Physics Prize (Voice of America News, October 9, 2007).
5. Patrick Donahue, "Nobel Prize Won by France's Fert, Germany's Gruenberg" (Bloomberg, October 9, 2007).
6. Hard-disk breakthrough earns French-German duo 2007 Nobel Physics Prize (AFB, October 9, 2007).
7. The Nobel Foundation - 2007 Laureates.
8. Quotation of Roberto Clemente.

October 09, 2007

It's Alive!

In a previous article, I described how scientists from the J. Craig Venter Institute have demonstrated the ability to replace the genome in one bacterium with that of another [1-3]. Although their process was successful in only about one in every 150,000 cells, bacteria reproduce so quickly that they were able to produce large bacterial colonies in a short time [4]. The supposed motivation for such work is the desire to create a genome de novo and have it replicated as an organism; that is, create an artificial life form. There is speculation that this has happened already, and an announcement will occur in a few weeks [5,6]. Perhaps the announcement will occur on Halloween, which might be an appropriate time.

The driving force behind this venture is Craig Venter. Venter was the founder of Celera Genomics, and he was one of the principals in the successful government-funded effort to sequence the human genome. Of course, creation of artificial life is definite Nobel Prize material, but Venter has a keen business sense as well. He's stated that "designer genome" bacteria could become new energy sources (e.g., the ethanol economy), and they could be designed to remove excess carbon dioxide from the atmosphere.

Aside from the ethical implications of this research, there's the potential problem of a designed bacterium wreaking havoc with the Earth's ecosystem. Experiments of this type are typically carried out with obligate anaerobic bacteria that die if exposed to air. However, the intended applications require aerobic organisms, so extreme caution is advised.

It's Alive! is a phrase from the movie, Young Frankenstein (1974, Mel Brooks, Director). In this movie (a very loose adaptation of Mary Shelley's "Frankenstein"), the brain of Frankenstein's creature was intended to be the preserved brain of Hans Delbrück. The brain was tagged, "Scientist and Saint," but Delbrück was actually an historian. He was, however, the father of Max Delbrück, who shared the 1969 Nobel Prize in Physiology or Medicine for his work demonstrating that bacterial resistance to virus infection is conferred by random mutation and not by adaptation.

1. Philip Ball, "Genome transplant makes species switch" (Nature Online, 28 June 2007, doi:10.1038/news070625-9).
2. Peter Aldhous, "Tycoon succeeds in 'genome transplant'" (NewScientist.com news service, 28 June 2007).
3. Matthew Herper, "Venter Takes Step Toward Synthetic Cells" (Forbes, June 28, 2007).
4. Carole Lartigue, John I. Glass, Nina Alperovich, Rembert Pieper, Prashanth P. Parmar, Clyde A. Hutchison III, Hamilton O. Smith, and J. Craig Venter, "Genome Transplantation in Bacteria: Changing One Species to Another" (Science Online, June 28, 2007, doi: 10.1126/science.1144622)
5. "Venter creates life! (cue lightening please)".
6. Ed Pilkington, "I am creating artificial life, declares US gene pioneer." (The Guardian, October 6, 2007)

October 08, 2007

Nano-Clay Composites

Biomimetic composite structures have generated much recent research. In a previous article, I reported on the composite structure of bone, which demonstrates an impressive combination of of strength and fracture toughness. Mother Nature has a definite advantage over scientists, since her techniques for "lay-up" of composites have been perfected by evolution over millions of years. An illustration of this problem can be found in some recent research on making the same type of composite found in sea shells [1].

Nacre, also called Mother of Pearl, is a composite of small platelets of aragonite, a crystal form of calcium carbonate (CaCO3) in an organic matrix of biopplymer. The aragonite platelets are about ten micrometers wide and a half micrometer thick, and they are arranged in a close-packed brickwork arrangement. As is typical for composites, the mechanical properties are a favorable combination of the strength of the hard aragonite and elasticity of the soft biopolymer.

Nicholas A. Kotov, a professor of chemical engineering at the University of Michigan, and his research team have been creating their own version of nacre using clay (aluminosilicate) nano-particles in a polyvinyl alcohol (PVA) matrix. PVA is an excellent choice as a matrix material, since it is water soluble, and its hydroxyl group allows bonding to hydrogen in the nanoclay. As a side benefit, the composite is transparent. The innovation that allowed lay-up of this composite was a robotic system that alternately dipped a carrier into a PVA solution, and then a dispersion of the nano-clay in a liquid [2]. There was a required drying step between these dips and subsequent cycles, and after three hundred cycles there was a layer thick enough for testing. Since the clay nano-particles are about a half micrometer thick, the three hundred cycles produced a layer with about a 150 micrometer thickness, or a few times the thickness of a human hair. Their measurements show that the stiffness and tensile strength of these composites are an order of magnitude greater than those of bulk nanocomposites, but it must be realized that the material preparation is quite tedious. A report on this work [3] is published in a recent issue of Science.

1. Nicole Casal Moore, "U-M research: New plastic is strong as steel, transparent" (University of Michigan Press Release, October 4, 2007).
2. The Layer-by-Layer Assembly and Ultra-Strong Materials (Michigan team web site).
3.Paul Podsiadlo, Amit K. Kaushik, Ellen M. Arruda, Anthony M. Waas, Bong Sup Shim, Jiadi Xu, Himabindu Nandivada, Benjamin G. Pumplin, Joerg Lahann, Ayyalusamy Ramamoorthy, and Nicholas A. Kotov, "Ultrastrong and Stiff Layered Polymer Nanocomposites," Science, vol. 318. no. 5847 (October 5, 2007), pp. 80-83.

October 05, 2007

The Man Aint Got No Culture

Charles Percy Snow (1905-1980) was an English physicist who, as we say in the labs, went over to the Dark Side; that is, he left scientific practice to become a bureaucrat. Physicists are good bureaucratic managers, since they are organized, analytical, data-driven, and they make quick decisions. A recent example is D. Allan Bromley, a physicist who was science advisor to George H. W. Bush. Although not active in science, Snow still maintained contact with the scientific world throughout his career, and among his close friends were G. H. Hardy, the prominent mathematician, and the physicists P.M.S. Blackett and J. D. Bernal. Bernal was the inspiration for the central character of a novel by Snow. A remark by Hardy in the 1930s caught Snow's attention. Hardy observed that the modern definition of "intellectual" did not seem to include himself, and physicists such as Rutherford, Eddington or Dirac. Perhaps inspired by this observation, Snow presented his ideas on this phenomenon at his famous lecture on the "Two Cultures."

The "Two Cultures" lecture was given on May 7, 1959, at the University of Cambridge. In this lecture, Snow highlighted the widening gap in understanding between science and the humanities, and he argued that educating people in both types of knowledge would allow the sort of thinking that would better solve the world's problems. Although he gave the example that many scientists have not read the classics and that artistic intellectuals know very little science, his further writing puts the blame squarely on the artistic intellectuals. Most scientists have read Shakespeare, but the artistic intellectuals have no knowledge of such basic scientific principles as the Second Law of Thermodynamics, or the definitions of mass and acceleration. Writes Snow,

"... the majority of the cleverest people in the western world have about as much insight into [physics] as their Neolithic ancestors would have had."

Today's world, beset by such scientific controversies as global warming and sufficient energy supply, needs leadership with at least a basic understanding of what all the fuss is about. For contemporary thought on the "Two Cultures" issue, I refer you to Seed Magazine. Seed has just published the winning essays in its Second Annual Seed Science Writing Contest, the topic of which was "What does it mean to be scientifically literate in the 21st Century?"

The phrase, "The Man Aint Got No Culture," comes from the lyrics of Simon And Garfunkel's "A Simple Desultory Philippic," from the record album, "Parsley, Sage, Rosemary and Thyme," released in 1966.

C. P. Snow, "The Two Cultures: And a second Look" (Cambridge University Press, 1965).

October 04, 2007

It Was, Like, Beep Beep Beep Beep Beebeebeebeep...

Today is the fiftieth anniversary of Sputnik 1, the first artificial satellite, launched into orbit by the Soviet Union on October 4, 1957. The Soviet Union launched not only this 184 pound, 23-inch diameter, sphere, but it launched a revolution in science and math education in the United States. I was ten years old at the time, and by the time I started studying mathematics and physics in earnest, it was the "New Math" and PSSC Physics [1]. I wrote about PSSC Physics in a previous article. About the only thing Sputnik did was transmit a beep-beep sound at 20.005 and 40.002 MHz, although modulation on the signal may have transmitted some scientific information. Sputnik fell back to earth just three months later, and this Soviet achievement was a wake-up call to the US to educate more scientists and engineers. The US lag in space technology was highlighted on Nov. 3, 1957, when Sputnik 2, carrying Laika, a dog and the first living being in space, was placed into orbit.

The US response, on December 6, 1957, was disappointing. The attempted launch of the first US satellite ended in the launch pad explosion of its Vanguard rocket. Sputnik 1 was nearly ten times heavier than the Vanguard satellite, which was only six inches in diameter. Sputnik 2 weighed 1,120 pounds, and the success of these early Soviet launches was a result of their using military ICBMs as launch vehicles, whereas the US had decided to use civilian technology. The first US satellite did not achieve orbit until January 31, 1958, and this was the satellite that detected the Van Allen radiation belt. Although the US space program, especially the unmanned missions to the planets, has had much scientific value, there is further value in the technology spin-offs of the space program, such as integrated circuits and the communications revolution that they enabled.

The phrase, "It was, like, beep beep beep beep beebeebeebeep...," is from an Apple Computer commercial of 2002. In this commercial, Ellen Feiss, a fourteen-year-old high school student complained about how her Windows computer failed (with the beep-beep sound) while she was writing a paper, and she needed to repeat her work. Feiss became an internet superstar overnight, which is very impressive since this was long before YouTube and other internet video sharing services.

1. The AAPT Celebrates PSSC's 50th Birthday
2. The week that was, Sputnik in 1957 (Seattle Times)
3. Peter Zimmerman, "One Giant Leap" (Wall Street Journal, page A23, October 1, 2007).
4. Gary Anthes, "Happy Birthday, Sputnik! (Thanks for the Internet)" (Computerworld, September 24, 2007).

October 03, 2007

MIT Entrance Exam (Part II)

In yesterday's article, I presented the algebra portion of the MIT entrance exam given on June 7, 1869 [1]. U.S. News & World Report ranks MIT as the best Engineering school among doctoral granting universities [2]. Today, in my final installment, I present the geometry portion. There are two other portions that I won't present. One is on arithmetic (too easy), and the other is on the English language and literature (too dated). Like the algebra problems, these geometry problems may seem simple to my Honeywell readership, but they should remember that the students taking this test were just high school educated, and 1869 was nearly 140 years ago. This would have been an exam one of my great-great-grandparents might have taken (if they had not been in Italy or Poland at the time). Of course, mathematics is timeless.

• Prove that the sum of the three angles of a plane triangle equals two right angles.

• Prove that the diagonal of a parallelogram divides it into two equal triangles.

• Prove that the area of a trapezoid is equal to the half sum of its parallel bases multiplied by its altitude.

• Prove that the side of a regular hexagon inscribed in a circle is equal to its radius.

• The radius of a circle equals 10. Find its area.

• The perpendicular dropped from the vertex of the right angle upon the hypothenuse divides it into two segments of 9 and 16 respectively. Find the lengths of the perpendicular, and the two legs of the triangle.

• Define similar polygons. To what are their areas proportional?

1. Source: MIT entrance exam, 1869-1870.
2. Best Undergraduate Engineering Programs (At schools whose highest degree is a doctorate).

October 02, 2007

MIT Entrance Exam (Part I)

Long before the SAT, universities administered their own entrance exams. The Massachusetts Institute of Technology (MIT), founded in 1861, gave the following questions on its entrance exam of June 7, 1869 [1]. U.S. News & World Report ranks MIT as the best Engineering school among doctoral granting universities [2]. These problems may seem simple to my Honeywell readership, but they should remember that the students taking this test were just high school educated, and 1869 was nearly 140 years ago. This would have been an exam one of my great-great-grandparents might have taken (if they had not been in Italy or Poland at the time). Of course, mathematics is timeless.

• If e = 8, find the numerical value of the following expression:

e - {√(e+1) +2} + (e - 3√(e))(√(e-4)).

• Simplify the following expression by removing the brackets and collecting like terms:

3a - [b + (2a - b) - (a-b)].

• Multiply 3a2 + ab - b2 by a2 -2ab -3b2 and divide the product by a + b

• Reduce the following fraction to its lowest terms:

(X6 +a2x3y)/(x6 -a4y2)

• Simplify:

[((a+b)/(a-b)) + ((a-b)/(a+b))] / [((a+b)/(a-b)) - ((a-b)/(a+b))].

• Solve:

((3x - 4)/2) - ((6x -5)/8) = ((3x - 1)/16).

• Solve:

7x - 5y = 25
4x - 3y = 11

Tomorrow - Geometry

1. Source: MIT entrance exam, 1869-1870.
2. Best Undergraduate Engineering Programs (At schools whose highest degree is a doctorate).

October 01, 2007

Catalyst Nano-Stamping

When I studied Thermodynamics in graduate school, one thing that was emphasized is that thermodynamic calculations will tell you what reactions are possible, but these reactions may not occur spontaneously. One prime example is the thermite reaction in which iron oxide (Fe2O3) is reduced by aluminum to form aluminum oxide (Al2O3). This reaction is highly exothermic, and it is thermodynamically favored, since the free energy change is a huge -200.6 kcal/mole. All this notwithstanding, mixed powders of iron oxide and aluminum will not react spontaneously at room temperature, since an energy barrier to reaction must be overcome. This is typically done by ignition of a magnesium strip, after which the reaction is self-propagating. In many industrial processes, a catalyst is used to prod a reaction to completion. The textbook example of this is conversion of a hydrogen-oxygen gas mixture to water. The mere combination of these gases will not produce water, but the presence of platinum, which acts as a catalyst, causes the explosive reaction to proceed. Humans are also more direct beneficiaries of catalysis, since coagulation of blood is a catalytic reaction. The catalytic nature of coagulation speeds the process to provide a quick hemostatic plug at an injury since it greatly amplifies an initial stimulus.

Nano-stamping, also known as microcontact printing, is one method presently researched for the production of useful nanoscale devices. As in any transfer stamping process, an "ink" is applied to a stamp, which is pressed against another material to allow transfer of the ink. This process has been investigated extensively by George Whitesides at Harvard. One problem with this process is diffusion of the ink during transfer, which makes the stamped pattern less distinct than the pattern on the stamp. The traditional stamping process cannot achieve a resolution of better than 100 nanometer.

Now, a research team at Duke University have invoked catalysis to bring the resolution of stamping to near one nanometer resolution [1]. In a paper published in a recent issue of the Journal of Organic Chemistry [2], the authors report on a stamping process in which a stamp of polyacrylamide was used to apply the enzyme, exonuclease I, a biological catalyst, onto a gold surface previously coated with fluorescently tagged single-strand DNA. As implied by its name, the exonuclease enzyme broke the DNA chains, thereby removing the fluorescent tags. What remained was a pattern of fluorescent dots about 100 nanometers in size, but with a position accuracy of about a nanometer. The position accuracy was a result of the DNA being firmly attached to the substrate, so motion could not occur. It will be interesting to see whether the process can be applied to materials useful to fabrication of electronic devices on silicon.

1. Monte Basgall, "Using catalysts to stamp nanopatterns without ink" (Duke University Press Release, September 26, 2007).
2. Phillip W. Snyder, Matthew S. Johannes, Briana N. Vogen, Robert L. Clark, and Eric J. Toone, "Biocatalytic Microcontact Printing," J. Org. Chem., vol. 72, no. 19 (September 24, 2007), pp. 7459-7461.