Akron Phy sics Club
Meeting Announcement: MONDAY, January 28, 2008 - TANGIER, 6:00 PM
For our first meeting of 2008 our speaker will be Tim Mann, Vice-President of the Schantz Organ Company of Orville, Ohio, who will be enlightening us about the
PHYSICS AND CONSTRUCTION
LARGE PIPE ORGANS
— a subject in which he is well versed, for the Schantz Organ Company is the largest and oldest pipe organ builder in the nation (still under the ownership of the founding family)— and it has been building pipe organs since 1873. In 2007 the company’s projects included organs in churches from Tempe, Arizona to Mobile, Alabama, and it is currently restoring the massive instrument in the Rockefeller Memorial Chapel at the University of Chicago (an organ built in 1928, but one with many dead pipes since it sustained water damage and debris from sloppy ceiling repair in the 1970s). The company is dismantling and removing its 7000 pipes, which range in length from three-eighths of an inch to 32 feet. According to University of Chicago organist Thomas Weisflog, after restoration and revoicing, “the sound is going to be just thunderous. You will literally feel the sound when it’s played. This whole place is going to vibrate.”
Minutes, January 28, 2008
Our January meeting attracted an audience of 35 members and guests, a record attendance that included two students of Bob Erdman — Reid and Tracy Parsons— together with visiting organists Joanna Butler, Carolyn Curtis, Nancy Robinson, and Scott Duncan. Before presenting the speaker who had attracted such a prestigious assemblage, Chairman Ernst von Meerwall called on Treasurer Dan Galehouse (who was present in person!) for a statement of our wealth — which, he was reluctant to report, had increased from $162.60 to $214.60, thereby increasing his responsibilities.
And in a second item of club business, Program Chairman Sam Fielding-Russell gave us a rundown on our programs for the remainder of the season:
February 25: Dr. Amy Milsted
Prof. of Biology, University of Akron
March 24: Dr. Bryon Anderson
Prof. Of Physics, Kent State University
“The Electric Form Factor of the Neutron”
April 28: Richard Goettler
Rolls Royce Fuel Cell
“Solid Oxide Fuel Cells"
May 19 (Third Monday): Daniel Akerib
Case Western Reserve University
Chairman Ernst advised that the University of Akron, and its Physics Department, are not yet finished with changes to their websites, and this may affect the accessibility to our club’s website, built and maintained by Webmaster John Kirszenberg: http://physics.uakron.edu/APC/news.htm
At which point Ernst introduced our speaker, Tim Mann, Vice-President of Schantz Organ Company of Orville, Ohio, the largest and oldest pipe organ builder in the nation still under the ownership of the founding family. The company has been building pipe organs since 1873, when the means to distribute air to the sets of variegated whistles that comprise these complex wind instruments was substantially different from today’s technology.
Entitling his presentation “Pipe Organ Building 101,” our speaker began by introducing the components: the console, the blower, a reservoir bellows, the windchest, and “ranks” of pipes, which are plugged into holes in the top of the wooden windchest.
While achieving his degree in organ from Indiana University, Tim spent three years building and “voicing” organs at the Holtkemp Organ Company of Cleveland. He recalled that, “In this time period I spent a lot of time studying how pipes produce sound. And most of this is just pure physics: taking columns of air and setting them into vibration, and, depending on how the pipe containing that column of air is constructed, whether it’s capped or fully open, tapered, partially open or mostly closed, it is the geometry of the pipe that determines its tonal quality. It is this artistic practice that we think about rather than the physics behind in achieving the musical result.” Accordingly, the account that follows has been augmented by contributions from Chairman Ernst and other sources to address the physics and engineering of pipe organs in a bit more detail.
Tim likened the console to “the command and control center” of the instrument. It is, of course, the home of keyboard (or several parallel keyboards or “consoles”) with multiple “stops” at the sides or top, which, when pulled, turn on the various ranks of pipes; and there are foot pedals that are usually bass notes. Fifty to as many as a hundred stops (each controlling the windchest of a separate rank) are common in large churches. Since each rank usually contains 61 pipes, having 6100 pipes in a church organ is not uncommon. The organ in the First Congregational Church in Los Angeles has 265 stops; and the Atlantic City Convention Hall (the largest in the U.S.) has 852 stops, controlling 33,114 pipes.
For half a millennium, classic pipe organs used strips of wood running from each key to mechanically control the flow of air. The keys (and stops) on today’s organs are electric switches. Since, on larger organs, the bundle of wires from the keys and stops to the electro-pneumatic valves has often become a cable several inches in diameter, computer software has since been devised to handle this myriad of data electronically by polling all the keys and stops many times per second and transmitting the multiplexed signals via one (or several) coaxial cables. These signals are decoded by a central computer, which signals the valves. Very different from the organ played by Bach!
Air pressure is generated in today’s organs by a centrifugal fan driven by an electric motor. The assembly is enclosed in a soundproof box, the air feeding into a weighted rectangular reservoir bellows, which maintains a constant pressure of 21 inches of water (which is less than one pound per square inch: 0.759 psi). If, during quiet passages, or even if the organ is silent for several minutes, there is more air than needed and the reservoir bellows is filled, the centrifugal fan is designed to spin idly without raising the pressure significantly. Although it does the job well, this is obviously not a very efficient pneumatic pump design — which is probably why the electric motor, even for a small 10-rank organ, is a half-horsepower, while larger organs need as much as 7.5 horsepower. The technology is in contrast to classic mechanical organs, whose more efficient (huge, triangular) bellows were mechanically pumped by a single choirboy — whose continuous-operation capability would probably be about a quarter horsepower. Theater organs (and, no doubt, the Atlantic City Convention Hall above) use higher air pressures.
Which brings us to the essence — the voice — of the instrument: the organ pipes. Each rank usually consists of 61 pipes, which comprise five octaves — each octave containing 12 black-and white keys (or “semitones”). The length of an open-ended pipe is half the wavelength of the sound produced. Five doublings of pipe length means that the longest pipe in a rank is 32 times the length of the shortest pipe. Thus, an organ whose lowest bass note is a 16-foot pipe “C” will find successive higher Cs at 8 feet, 4 feet, 2 feet, one foot and half a foot. And the largest organs that go an octave lower have 32-foot pipes. The pipes are fabricated from cast sheets of a tin-lead alloy (from 30% to 90% tin). Interestingly, the more tin in the alloy, the “brighter” the sound (and the more expensive the pipe). Some (low-pitch) pipes are made of wood, and have a rectangular cross section.
Pipes that are essentially pneumatic whistles are called “flue” pipes. Flue pipes have no moving parts and generate their sound by vibrating air in a column like a flute or recorder. Reed pipes have an actual mechanical reed, like a clarinet or saxophone, at the base (except that in a pipe organ the reed is made of brass) and have a resonator column above.
While the distance between two open ends of a pipe is one-half wavelength for its fundamental frequency (pitch), the distance between the closed end of a pipe and its open end is one-quarter wavelength. The question under what conditions a pipe considers the input end closed rather than open is subtle and depends on details, which may well vary between types of organ pipe, as it does between different wind (or brass) instruments. Open-closed pipes exhibit only odd harmonics, while open-open pipes have the full harmonic spectrum. Partially covering the open end by insertion of a tube, or any partial plug, affects not only the proportion among the harmonics produced, but also, very substantially, the fundamental pitch of the pipe. As a general rule, the narrower the pipe, the more of the higher harmonics it will have. And straight pipes have greater amplitudes of the higher harmonics than tapered pipes.
All these subtle variations result in selected combinations of harmonic overtones, which are perceived by the human ear (and mind) as the “color” of the tone produced. Most have been empirically developed over the last four hundred years in an effort to imitate the sound emitted by orchestral instruments, including wind, brass, strings, and woodwinds. Drilling a hole at the midpoint of the pipe raises the pitch by an octave and produces a characteristic flute sound. Changing the diameter of the pipe alters the color from an “eee” sound to an “ahh” to an “ooo.”
Our speaker pointed out that the differences and imperfections that blend in the output of pipe organs give an organ (and the room in which it is played) its characteristic sound. Tim pointed out that is analogous to what we hear in the blending of the instruments in a symphony orchestra — since, as a practical matter, in tuning the strings for example, not every musician exactly matches the 440 Hertz “A” (or whatever the value exactly comes out) emitted by the oboe that evening [the oboe, a double reed horn, is chosen because it is one of the most difficult instruments to tune]. Indeed, depending on the individual musician’s sense of pitch in tuning his violin, there can be as much as a quartertone difference between instruments.
Tim showed us scores of church interiors in which Schantz organs have been installed. A typical time schedule to manufacture and install a pipe organ is, he said, 18 to 20 months. But from initial contact until completion (including design for the aesthetics and acoustics of the chamber in which it will operate, and the preferences of the congregation), ten years sometimes elapse. Tim pointed out that pipe organs are not cheap. A modest-size organ with 10 or 15 ranks will cost from $12,000 to as much as $30,000 per rank, for a total cost of $150,000 to $200,000. But this is on the low side. The budget for the 134-stop organ restoration described in the last paragraph was $2.1 million.
One of the company’s current projects has been restoring the massive instrument in the Rockefeller Memorial Chapel at the University of Chicago (an organ built in 1928, but one with many dead pipes since it sustained water damage and plaster debris from a sloppy ceiling repair in the 1970s). Schwantz has been dismantling and removing its 7000 pipes, which range in length from 3/8 inch to 32 feet. According to University of Chicago organist Thomas Weisflog, after restoration and revoicing, “the sound is going to be just thunderous. You will literally feel the sound when it’s played. This whole place is going to vibrate.”
Meeting Announcement: MONDAY, February 21, 2008 - TANGIER, 6:00 PM
Speaker for our February meeting will be will be Dr. Amy Milsted, Professor of Biology, the University of Akron, and, since 2001, a Fellow, the American Heart Association, Council for High Blood Pressure — which organization is the sponsor of one of her current research projects. Her subject is one that is intimately familiar to albeit unwanted by many of us:
It is subject on which Dr. Milsted has been conducting research for years, as evidenced by the string of papers she has published (e.g., studying the influence of testosterone on blood pressure). Her previous appointments include service at the Cleveland Clinic, the Veterans Administration Medical Center, Case Western Reserve Department of Medicine, and Carnegie-Mellon University in Pittsburgh.
Minutes, February 21, 2008
Our February meeting had five visitors we rarely get to see: Pat and Katherine Reilly, Ken and Janice Gui, and Claire Tessier (who gave us a program last February on “The Biomineralization of Silicon”).
For openers, Chairman Ernst von Meerwall called on Treasurer Dan Galehouse for a report of our wealth. Dan advised that, because Tangier charged us less than $18 per meal last time, this unexpectedly resulted “in a lot of extra money in the treasury,” but he wasn’t “in a position to commit on how much money we are going make.” Later, however, after resorting to empirically counting the money in the metal box that serves as our club’s vault, and after paying Tangier for our dinner (using neither a calculator nor a slide rule — mine resides in its leather scabbard in the top drawer of my desk), he reported a new treasury balance of $306.67 — which is probably a record high since the club was reorganized in 1990. We offer our thanks to Dr. Dan for his continuing to perform this thankless job.
Called upon for a review of programs he has lined up for the rest of the year, Program Chair Sam Fielding-Russell reviewed the list:
March 24: Dr. Bryon Anderson
Prof. Of Physics, Kent State University
“The Electric Form Factor of the Neutron”
April 28: Richard Goettler
Rolls Royce Fuel Cell
“Solid Oxide Fuel Cells"
May 19 (Third Monday): Daniel Akerib
Case Western Reserve University
Our leader then called on Webmaster, John Kirszenberg, for a report on how things were going with his meetings with the University of Akron with regard to our website: http://physics.uakron.edu/APC/news.htm John had good news: Not only is the University going to stay with the same server it has had, but our website is now listed on the U of A’s Physics Department Main Page. And the great thing this does, he explained, is that if one calls up Google and types in “Akron Physics Club,” up pops our the link to our site. “So,” John announced, “we now have international presence.” Your secretary has tried it and it works!
Between Charlie Wilson, Ernst, and Claire Tessier herself, we learned that Claire is featured in the current issue of Chemical and Engineering News. The occasion is the 40th anniversary of an American Chemical Society project of which she was the third graduate. Between her junior and senior years of high school, the program sent her to the University of Vermont for the summer — an experience that caused her to choose chemistry as a career (she is currently the University of Akron’s Professor of Chemistry). The magazine story not only featured her picture, but also her personal logo, which spells her first and last names in the symbols of chemical elements: C La I Re Te S Si Er (carbon, lanthanum, iodine, rhenium, tellurium, sulfur, silicon, erbium). It is apparent that Claire’s career was predestined.
Which brought us to the introduction of our speaker, Dr. Amy Milsted, Professor of Biology, the University of Akron, who, with degrees in cell biology, education, and chemistry, is also a Fellow, the American Heart Association, Council for High Blood Pressure — obviously an appropriate speaker for the subject of her talk: Hypertension.
Before we get into the details of her current research, since your secretary was privileged to have dinner at the same table with our speaker, he thought the reader might be interested in some of the things we learned (and subsequently studied) about the physics of blood pressure. The often-quoted normal blood pressure reading of 120/80 is measured in millimeters of mercury (which translates into 2.3/1.5 pounds per square inch). The second number, the “diastolic” reading, is the static pressure — the minimum pressure when the heart is at rest between beats. The first number, the “systolic” pressure, is the maximum pressure that occurs with the beat, and this value usually increases with age, typically going from 120 to 140 mm Hg (2.7 psi). This happens, Dr. Milsted explained, because the blood vessel walls become less elastic as they age; their diameters, which expand slightly with each beat, stretch less and, consequently, are less effective in damping the peak pressure.
This loss of flexibility is mostly due to the walls of the blood vessel network thickening with age. Another factor affecting blood pressure is the deposit of plaque in these vessels, which further reduces their interior cross sectional area, increasing the resistance to flow. So the sympathetic (or autonomic) nervous system increases the blood pressure by making the heart pump harder to maintain a sufficient flow to nourish the organs and muscles it serves. Some organs have their own regulatory defenses, e.g, when systolic blood pressure falls below 100 mm Hg, the kidneys release the enzyme renin into the bloodstream, stimulating the heart. Although the structure of the pipes and the pump in this system are made of flexible tissue, the same basic laws apply to blood flow as they do in other hydraulic (or electric, or heat flow) systems: flow is equal to pressure (psi — voltage — temperature difference) divided by the resistance. Too much salt in one’s diet increases the volume of fluid in the circulatory system, raising blood pressure. Exercise temporarily raises blood pressure because of the increased demands of the body. Although the hearts of babies beat faster than those of adults, infants have much lower blood pressure because their heart is pumping against less resistance.
Our speaker pointed out that more than 80 million Americans have one or more kinds of cardiovascular disease: high blood pressure, coronary heart disease (which is the biggest killer of Americans) heart failure, stroke, and/or various congenital diseases. The prevalence increases with age. By the time we get into our eighties, 83% of men and 90% of women have some form of cardiovascular disease. Many more people die of cardiovascular disease than they do of cancer (or anything else). One in three of us has hypertension, which is defined as a systolic blood pressure reading greater than 140 and/or a diastolic greater than 90). Hypertension is associated with a reduced life expectancy and is the most important risk factor for stroke. It can damage the brain, heart, eyes and kidneys. Contributing factors include stress, too much salt, and/or lack of exercise; but the cause of 95 % of hypertension cases is unknown — and for reasons known only to medical linguists, it is therefore called “essential” or “primary” hypertension.
Our speaker displayed a chart showing the differences in high blood pressure occurrence between the sexes. It was apparent that until middle age, men have a higher rate than women; but after menopause, women (with the decline of estrogen) match men in prevalence. And above 65, many more women have hypertension than men.
So what can be done about hypertension? The first effective inhibitor was discovered in the 1970s in the South American jungle in the venom of a viper that disabled its prey (including the humans working in the jungle) by dramatically dropping their blood pressure. Its effect was to block a protein that becomes a peptide (angipepsin 2), which causes blood vessels to constrict. The essence of this snake venom is the basis of many of the prescribed hypertension medications today (e.g., ace inhibitors). They essentially relax the blood vessels, increasing their diameter. Alpha- and beta-blockers reduce the strength of the nerve signals to the heart. Diuretics flush out water and sodium. Calcium channel blockers keep calcium ions from entering the cells of the heart, There is a dizzying number of drug names that have subtle, nuantic differences in their effects.
Amy Misted’s research has been studying the effects of genetics in hypertension, for which there is ample evidence. Several studies have shown that the Y-chromosome (which exists only in males; ladies have two Xs) is associated with high blood pressure. African-Americans have a higher prevalence of high blood pressure than European-Americans. But since they can’t experiment on people, Amy’s group works with rat colonies — including one variant with a high incidence of hypertension. Rats make excellent models because the effects of hypertension on their various organs matches experience in humans. To take the blood pressure of rats, our speaker’s research group usually uses a small cuff surrounding the tail close to the rat’s body. It is now possible, however, for them to implant a wireless transducer in the aorta.
It is possible to have two generations of rats a year (“a two-year-old rat is a very old rat”), but Amy’s group usually keeps rats for only 15-20 weeks. Nearly two decades ago, the group crossed spontaneously-hypertensive male rats with hypertensive females, and did a similar crossing with those having no history of the disease. Predictably, the first group produced offspring with extremely high blood pressure (above 200), and the tension-free rats results begot children with normal blood pressure. Then they began mixing them up, finding that the results were sharply different depending on whether the mother or the father was the one with high blood pressure. The differences were as much as 230 vs. 150 mm Hg.
The conclusion of the study was that it is the Y-chromosome (found only in males) that has a significant effect on the inheritance of hypertension. The next step was to investigate the components of the Y-chromosome. They concentrated on a group called SRY, meaning “sex-determining region on the Y,” the gene that causes the sex-neutral embryo to become a male. There are a number of DNA combinations in the Y-chromosome that control other inheritances, and Amy’s group set about to find the one that transmitted hypertension. To this end, they had DNA from the rats assembled into what they call a “genomic library,” from which they have found six different copies of SRY (designated as SRY-1 through SRY-6) in the rats’ genome.
One of these, they reasoned, had to be responsible for blood pressure. So the group did mini-operations on six rats with normal blood pressure to deliver the different SRY gene combinations to the rats’ kidneys, and we saw charts of the results, together with those of control rats. As it turned out, the SRY-1 sequences significantly affected blood pressure because it released a neuro-peptide that caused the blood vessels to contract. SRY-2 caused no difference in blood pressure, even though the differences in their proteins are small. The group has gone on to study those differences, and we saw how rat cells into which the various DNA combinations had been introduced multiplied (in two weeks time) in a Petri dish.
A major finding of Amy Milsted’s research to date is that it has now been demonstrated that SRY-1 is heavily involved in the inheritance of hypertension (although it is probably not the only hereditary influence). She is working on many other possibilities, including factors that influence the genes of the African-American male. There were lots of questions after her talk, during which we even learned about the diet of the rats in her care.
Meeting Announcement: MONDAY, March 24, 2008 - TANGIER, 6:00 PM
It has been five years since we have been privileged to hear Dr. Bryon Anderson, now Chair of Kent State University’s Department of Physics. In January 2003, Prof. Anderson treated us to a delightful presentation on “The Physics of Sailing” — which, in October of the same year, precipitated his book, “The Physics of Sailing Explained” (currently available from Amazon.com). And his article on the same subject appears in the February issue of Physics Today, with the issue’s cover picture entitled “Wings on the Water.” Our speaker is also the author of more than 200 papers published in scientific journals in experimental nuclear physics. In which regard he is eminently qualified to present our March program, entitled:
THE ELECTRIC FORM FACTOR OF THE NEUTRON
About which Dr. Anderson explains, “Since about 1935 it has been known that the proton and neutron are not elementary, i.e., point, particles. The charge distribution of the proton was nicely determined in the 1950's by high-energy electron scattering. The neutron was studied also and found to have charge, with a positive core surrounded by a negative outer layer, yielding no net charge. Because there are no pure neutron targets, one must use deuterium or helium and the motion of the neutron in these nuclei makes extracting the neutron distribution inherently inaccurate.
“Recently, it has become possible to determine the charge distribution of the neutron by measuring the spin transfer from a polarized beam of electrons scattered by a neutron. This method eliminates most of the inaccuracies associated with simple scattering and is leading to greatly improved results for the charge distribution of the neutron. These results now provide some of the most sensitive tests available of models of the structure of the nucleon.” Our speaker will discuss these measurements and compare them with theoretical models.
Minutes, March 24, 2008
Our February meeting had three welcome visitors, Saunis Parsons, together with student sons Reid and Tracy. All were introduced by Chairman Ernst von Meerwall, following which he called on Treasurer Dan Galehouse. Dr. Dan was obviously somewhat dismayed to report a new treasury balance at the beginning of the evening of $304.60 — the highest our (dues less) club’s wealth has ever been in its eighteen years of existence. Worse than that, he admitted, by the end of the meeting that the treasury would soar to $312.60 — threatening our status as the cheapest club in Akron!
Called upon for a reminder of the final two programs in store before our summer hiatus, Program Chair Sam Fielding-Russell listed:
April 28: Richard Goettler
Rolls Royce Fuel Cells
Solid Oxide Fuel Cells
May 19 (Third Monday): Daniel Akerib
Case Western Reserve University
Which brought us to the anticipated hour for Ernst to introduce our speaker, Prof. Bryon Anderson, now Chair of Kent State University’s Department of Physics — from whom we have previously been privileged to hear three times over the years, speaking on a variety of subjects: stars and planets, neutrinos, and sailing. His most recent presentation subsequently became a book, The Physics of Sailing Explained, which was featured in the in the February issue of Physics Today, with a cover picture entitled Wings on the Water. (Dr. Anderson has two boats, one of which he sails on Lake Erie, and a 33-footer he has already taken out for the first time this year on Chesapeake Bay – and yes, armed with his knowledge (and a sophisticated computer-navigating device), he can operate it without a crew.
Dr. Anderson’s topic this time was The Electric Form Factor of the Neutron, a subject to which much of his research has been devoted for years at Jefferson Laboratory. Virginia. He showed us an aerial view of the $500 million facility (at least a billion in today’s dollars) — a cluster of buildings surrounded by a heavy concrete underground tunnel in the shape of a rectangle about half a mile long with rounded ends, Employing about 30 scientists and technicians, its operation is funded by the National Science Foundation. In the tunnel, electrons are accelerated to a velocity so close to the speed of light that the spherical shape of the minute particles is relativistically flattened to become discs in the direction of their motion. The high-velocity electrons are released into three five-story rooms (with four-foot thick walls) containing massive arrays of detectors.
Since about 1935 it has been known that the proton and neutron are not elementary, i.e., point, particles. Both are now known to be composed of quarks. The charge distribution of the proton was nicely determined in the 1950s, our speaker explained, by high-energy electron scattering. But the neutron is more interesting than the (positively charged) proton because, although the neutron has no net charge, it was found to have a positive core surrounded by a negative outer layer.
Because there are no pure neutron targets, and since hydrogen’s most common nucleus consists of a single proton, one must use deuterium (whose nucleus consists of one proton and one neutron) or an isotope of helium. The motion of the neutron in these nuclei makes extracting the neutron distribution inherently inaccurate because it is a moving target. Moreover, the lifetime of a free neutron is about ten minutes. One can, however, measure momentum transfer, and by comparing the scattering from these nuclei with that from hydrogen, one can measure both the magnetic and the electric form factor. This was the state of the art until the 1990s when the Jefferson Laboratory was built.
With the new tools available (including the requirement to cool the target to one or two degrees Kelvin and to measure time of flight to 1.5 millionths of a second) it became possible to refine greatly the determination of the charge distribution of the neutron by measuring the spin transfer from a polarized beam of electrons scattered by a target containing partially polarized neutrons, and to obtain precise determinations of the ratio of the electric form factor to the magnetic form factor. These methods have eliminated most of the inaccuracies associated with simple scattering and they are leading to greatly improved results for the charge distribution of the neutron. These results now provide some of the most sensitive tests available of models of the structure of the nucleon.
Our speaker discussed the results in detail, comparing them with theoretical models and with plots of previous work. The reduction in the error bars on the points in recent modern era curves when compared with older plots was dramatic. But work is still in progress, Dr. Anderson said, at locations all over the world.
After attempting to process the above through this engineer’s neurons and receiving some welcome assistance from Chairman Ernst (whose helpful e-mail was entitled Getting a Charge Out of the Neutron!) your secretary found solace in John Updyke’s couplet about yet another subatomic particle:
Neutrinos: They are very small,
And do not interact at all.
Meeting Announcement: MONDAY, April 28, 2008 - TANGIER, 6:00 PM
Our speaker for April will be ceramic engineer Richard Goettler, manager of the fuel cell development team of Rolls Royce Fuel Cell Systems (US), Inc., in North Canton. His subject is:
SOLID OXIDE FUEL CELLS
It is a technology on which our speaker has been working for a dozen years, first at McDonnell Douglas (Boeing) and then at McDermott/Babcock & Wilcox. Rolls-Royce Fuel Cell Systems is developing solid-oxide fuel cell systems for megawatt scale, stationary power generation applications. The company’s hybrid power generation system, he says, will be clean, quiet, compact, fuel-efficient and cost competitive. Field tests are planned for 2008. Rolls-Royce believes the most promising applications for the solid-oxide fuel cell will be for stationary power generation units in such applications as hospitals, universities and shopping malls.
Minutes, April 28, 2008
As is his wont, Chairman, Ernst von Meerwall opened the meeting by calling on Treasurer Dan Galehouse for a report on the health of our treasury. Dr. Dan’s response was even more multi-faceted than usual. It seems that Tangier (whose recently-leased-out business has now returned to owner Edward George) somehow charged us only $15 for our dinners in March (instead of the usual $18), resulting “in a lot of extra money in the treasury” (if indeed, one can characterize less than a hundred dollars as a bonanza). At any rate, because of the turnout for the April meeting, the bottom line had become even greater, going from $312.60 to $338.50 — thus preserving our reputation as the cheapest club in Akron.
Bob Erdman (who had brought guest James Brown for the evening) asked to be heard with his salute to Milian France, who has been our Nametag Marshal (and dispenser of cheerfulness and fun and innovative ideas) for several years, including the unwelcome news that she is planning to move to Albuquerque this summer — possibly before the next meeting. Milian received a hearty salutation of applause, albeit with a hint sadness. We’ll miss her!
Chairman Ernst then turned to Program Chairman Sam-Fielding Russell, who, after previewing Dr. Akrerib’s “Dark Matter” talk, announced above, repeated his plea for suggested topics for our new season beginning in September — together with speakers for same. But, Sam cautioned, please help avoid scheduling problems by not committing him/her to a specific date.
At which point Chairman Ernst turned the meeting over to Founder, First President, and By-Laws Author Charlie Wilson for the solemn ceremony of election of club officers for our club for the year to come. Charlie had put out requests for nominees, he said, but his relatively few responses, he said, “were pretty monotonous,” he said. Most offered something like “the best we could do is hang onto the ones we’ve got!”
Accordingly, Charles III posted the following as proposed Officers of Akron Physics Club for 2008-2009. And he added his personal appreciation to Milian France for her service as Nametag Marshall, together with the news that Bob Erdman has agreed to assume her post:
|Chairman||Ernst von Meerwall|
|Vice Chairman||Darrell Reneker|
|Program Chairman||Sam Fielding-Russell|
|Program Vice-Chairmen||Leon Marker & Bob Hirst|
|Associate Secretary||Jerry Potts|
|Associate Treasurer||Kevin Cavicchi|
|Nametag Marshal||Bob Erdman|
|Reservations Secretary||Charlie Wilson|
There was a barely audible second to Charlie’s motion. Chairman Ernst asked if there were further nominations. None was offered. He asked whether the current nominees were willing to serve. Embracing a political strategy in sharp contrast to the current national primary contest, not a single candidate uttered a word. Breaking the deathly silence, Charlie moved that the people on the slate be elected by acclamation — ultimately receiving a chorus of ayes. There followed a solitary muted cheer.
To the relief of the assemblage it had became time to introduce the speaker, ceramic engineer Richard Goettler (son of Lloyd Goettler, from whom we have heard, and whose work was recently featured in Physics Today). His subject was “Solid Oxide Fuel Cells.”
Richard Goettler is manager of a group of about 35 scientists and others at Rolls Royce Fuel Cells in North Canton. He reminded those of us who still associate Rolls Royce with high-end passenger cars that the company sold off that division six years ago to BMW. In addition to civil aerospace, where the company is famous for its jet engines, Rolls Royce is also into marine turbine engines, oil and gas line service equipment and fuel cells for power generation, which is part of the company’s energy development effort. Rolls Royce’s R & D on fuel cells is unique in that it is 90% self funded. The fuel cell division is headquartered in the UK, where it has about 250 people (plus about half a dozen in Singapore, where a 25% of the activity is owned). Two years ago, Rolls Royce purchased the fuel cell division of Babcock and Wilcox, which is the North Canton facility headed by Goettler. RR’s effort represents the largest fuel cell R & D activity worldwide.
The initial goal of the Canton group is power-generation fuel cell systems in the one megawatt range, with the probability that they will work on increased capacity systems in the future. What makes fuel cells attractive in comparison with other energy sources is their electrical efficiency (currently 55% with the probability of achieving 65%), compared with reciprocating engines or gas turbine engines— which, at best, are about 45%. A coal-fired power plant is about 35%. Moreover, fuel cells represent a substantial reduction in CO2 emissions. The main market focus of fuel cells in this range is residential and automotive.
“Fuel cells,” our speaker explained, “are just one type of electrochemical cell. They’re just like a battery except that the chemical reactions are fed continuously to the cell. Charge transfer takes place between electrodes, and there is an electrolyte. For solid oxide fuel cells it is ion-conducting zirconium.” A major advantage of fuel cells is that it directly converts the chemical energy of the fuel to electrical energy.” (Operating in reverse, fuel cells can generate hydrogen — a source of water hydrolysis H2 for emerging hydrogen applications.)
Fuel cells, Richard said, have been around since the early 1800s (“and we’re still not making money off of them!”). It was a lawyer, William Grove (1811-1896) who began experiments with a platinum electrode in an electrolyte of sulfuric acid. In contrast to fuel cells for automobiles currently in the news (“these are low-temperature cells based on a proton-conducting membranes operating at 140 degrees C”), solid oxide fuel cells employ a solid ionic membrane transporting oxygen, not protons. Oxygen, introduced at the cathode is transported through the electrolyte (zirconium oxide, or zirconia) to the anode where it oxidizes hydrogen, releasing electrons to the circuit. Zirconia is mixed in a solid solution with yttrium oxide in which nickel particles are distributed (they contribute electrons to optimize performance). The cat-ion in the yttrium oxide replaces the zirconium cat-ion in the zirconium oxide, creating vacancies in the anion lattice. This allows for high mobility of the oxygen through the crystal lattice. Because a phase change is involved, the operating temperature of the fuel cell is in the range of 800 degrees to 1000 degrees C. The temperature is self-sustaining.
The equation describing fuel cell action is
E = RT/4F in which
R = Gas Constant
F = Faraday Constant
T = Temperature
The cells on which the Rolls Royce group generate one volt per cell with a current density of 400 to 500 milliwatts. Each is fabricated in several layers and is about ten inches long. These are stacked and arranged in “tubes,” each contributing 42 watts, with its thousand square centimeters of surface. These units are collected in bundles, which have a total capacity of 125-250 kW. A turbo-generator provides and controls gas pressure to the system and it adds about 10% to the power output. Unburned fuel is recycled. There are no heat exchangers.
A ready-to-roll system with a capacity in the one megawatt range is housed in a unit about the size of a travel trailer, and is designed to fit in a marine shipping container. 35 are being tested in Ohio; another 200 in the UK. Rolls Royce. Their price will be competitive with that of coal-fired plants which have a cost of $2300 per kilowatt, and with a vastly smaller carbon footprint. Exciting, innovative stuff!
Meeting Announcement: May 19, 2008 - TANGIER, 6:00 PM
Our last meeting of the 2007-8 season features an intriguing (if little-understood) topic currently mentioned in the pages of scientific journals and even in weekly news magazines. On March 19 [a week early this month] Dr. Daniel Akerib, Professor and Chair of Case Western University’s Physics Department (who is also a member of the Cryogenic Dark Matter Search operating in the Soudan Mine in Northern Minnesota) will speak to us on
As Dr. Akerib explains, “Overwhelming observational evidence indicates that most of the matter in the Universe consists of dark matter -- material unseen except for it's gravitational effects. One possibility is that the dark matter is Weakly-Interacting Massive Particles (WIMPs) that were produced in the early Universe. These relics could be in the Milky Way and be detectable through scattering off of atomic nuclei in a terrestrial detector. The detecting of WIMPs is a great experimental challenge because they interact at a low rate with small energy depositions, amidst much higher sources of background.”
Dr. Akerib will introduce the dark matter problem and the WIMP hypothesis, and he will discuss a range of the different techniques that he and his colleagues use in their attempts to detect them. These approaches include pucks of germanium operated at 50mK, buckets of liquified xenon instrumented with light-sensitive photomultiplier tubes, and the resurgence of bubble chambers from the heyday of accelerator-based particle physics.
Minutes, May 19, 2008
Attracted by the subject of the last program before our summer recess, Reservations Secretary Charlie Wilson reported a record attendance of three dozen, which included Founder Charlie’s visiting son, Will, plus five students from such diverse universities as Carnegie-Mellon, University of Pittsburgh and the University of Akron.
Chairman Ernst von Meerwall began our brief business meeting early — between our entree and dessert courses because Tangier’s Banquet Service (distracted by serving a mere 550 Browns fans upstairs) had forgotten that those us down in the obscure Wine Cellar room (in the basement!) were entitled. The chocolate meringue and cookie were delicious when they arrived a few minutes later, despite the simultaneous business meeting.
Our first order of business, as usual, was a report by Treasurer Dan Galehouse, who, after doing the accounting in his head, announced that we seemed to have a net gain of $28 for the evening. Receiving no reaction, he advised that “that’s a lot of money”— thus confirming our reputation as the cheapest club in Akron. But it got worse, as he later e-mailed me: It seems that after Bill Arnold insisted on reimbursing the treasury for some past student meals, our treasure has peaked at a new record high” of $384.60, plus a remaining Student Fund of $54! Further, as Treasurer Dan explained (after having run out of one-dollar bills at a critical point in the evening), “I went back and refunded those who were owed money; [but] apparently I missed one. So there is one unclaimed dollar that will have to wait in the polyethylene box [over the summer!] until claimed.” It now being fall, you are appropriately notified.
Called upon by Ernst, Program Chairman Sam Fielding-Russell advised that, following his and Charlie’s verbal and e-mailed entreaties to the membership, he now had nine suggestions for programs beginning in September; but these have yet to be scheduled with the speakers.
Which brought us to the reason for the record assemblage: Chairman Ernst introduced our speaker, Dr. Daniel Akerib, Professor and Chair of Case Western University’s Physics Department. Prof. Akerib is also a member of the Cryogenic Dark Matter Search operating two thousand feet underground in the Soudan Mine in Northern Minnesota, where he and his colleagues are researching Dark Matter. We had last heard from him eight years ago.
Our speaker declared that, since his last report in 2000, his group has continued to look for the elusive substance — “and we’re still looking for it.” There is overwhelming observational evidence, he said, that dark matter constitutes most of the matter in the Universe — material unseen except for its gravitational effects.
The reason for their extended search, he said, is to learn “what’s missing in the universe. We understand gravity and the origin of structure in galaxies, and we assume that Newton and Einstein got it right. We don’t know that that’s absolutely true on all the scales of the universe, but we take that as a working assumption in pursuing the cause of the forces that hold galaxies together.” They know it’s not ordinary matter and expect to find something that may be a new form of matter — which might also be an indication of some type of new fundamental force.
There is considerable dynamical evidence for the existence of dark matter. One of these is the rotation curve of particles in the galactic halo of objects rotating about their central masses. In our solar system, planets move slower in their orbits as they get farther from the sun, and one can readily predict their tangential speed from their orbital radius and the masses involved. But on a galactic scale, the speed of orbiting particles is substantially greater than conventional physics would predict, suggesting a much greater central mass. On an even larger scale are anomalies in galactic cluster lensing — the use of a large mass in space that happens to be in the line of sight with a more distant object whose light rays are warped around the closer mass cluster (the famous Einstein prediction), using it as a lens to magnify the more distant object (or cause multiple images of it to appear). But the optical density of the gravitational lens turns out to be about three times greater than that expected, implying a substantially larger mass of the closer cluster than would be expected.
A current theory that may be applicable in the study of dark matter is that of super-symmetry — a way of describing a new class of subatomic particles and the forces that govern their actions among themselves and with ordinary matter. It is possible, Dr. Akerib explained, that dark matter consists of Weakly-Interacting Massive Particles (WIMPs) that were produced in the first few minutes of the early Universe. These relics could be in the Milky Way and could be detectable through scattering off of atomic nuclei in a terrestrial detector. The current hypothesis is that dark matter consists of “clouds” of WIMPS permeating the galaxies like a cosmic gas.
Our speaker devoted most of the rest of his Power Point-illustrated lecture to answering the question, “How do we find this stuff?” The detecting of WIMPs,” he explained, “is a great experimental challenge because they interact at a low rate with small energy depositions, amidst much higher sources of background.” The particles themselves have no charge. It is like looking for a needle in a haystack, and the challenge is to get rid of as much of the “hay” as possible (one reason that the laboratory is half a mile underground to shield it from cosmic rays), using ultra-clean copper and other metals in the construction of their apparati, using noble gases, etc. The likelihood of detecting these rare events (e.g., when a WIMP and a quark happen to collide, i.e., a WIMP colliding with a nucleus), he said, is about a hundred million times less than that of ordinary background radiation of various ilk.
Dan went on to discuss a range of the techniques that he and his colleagues use in their attempts to detect them. Their approaches include pucks of germanium operating at 50 micro Kelvin, in buckets of liquefied xenon, instrumented with light-sensitive photomultiplier tubes, “and we have even seen the resurgence of bubble chambers from the heyday of accelerator-based particle physics.”
So far, after five years of “time exposure,” as our speaker put it, “we are the best in the world at finding nothing.” Partly, it is apparent that this is evidence of the group’s meticulous honesty in data evaluation with the necessary skepticism to avoid any optimistic (or pessimistic) influences. Dan Akerib’s fascinating presentation precipitated lots of questions and further discussion — and it inspired Tom Meyers to recall a quote posted on the wall in the Kent UU church, which was authored by British biologist J.V.S. Haldane: “The universe is not only stranger than we imagine; it is stranger than we can imagine.”
Meeting Announcement: MONDAY, September 22, 2008 - TANGIER, 6:00 PM
Appropropriately for a club of its acumen, the Akron Physics Club’s first meeting of the new season occurs precisely on the day of the autumnal equinox. And our speaker, from whom we haven’t heard since February, 2001, will be Dr. Jutta Luettmer-Strathmann, Associate Professor of Physics, the University of Akron. She will be speaking on:
LIQUID MIXTURES IN TEMPERATURE GRADIENTS
FROM THE PREBIOTIC OCEAN . . .
TO THIN LAYERS OF POLYMER-BLENDS
As Jutta explains, a temperature gradient applied to a fluid mixture generally induces net mass flows, which lead to the formation of concentration gradients. In quiescent mixtures, this effect is known as thermal diffusion or the Ludwig-Soret effect. In conjunction with convective flow, thermal diffusion becomes a powerful separation process that affects natural processes, and is an active area of current research.
Significant temperature gradients occur naturally under geological conditions. Thermal diffusion is well known to affect the partitioning of crude oil components in oil fields and is also currently being investigated in the context of carbon sequestration. Very recently, a mechanism, driven solely by a temperature gradient, has been proposed to solve the “concentration problem of the origin of life.” Jutta will describe recent discoveries in the field.
Minutes, September 22, 2008
Celebrating the Autumnal Equinox on the day, our first meeting of the new season attracted three tables of regulars, including this time Charles Lavan, who, before his retirement from Lockheed Martin, gave us two outstanding programs on automated high-altitude airships. And for the first time since founder Charlie Wilson turned over the reins to Ernst von Meerwall (who was conducting a seminar at George Tech on Monday) the meeting was chaired by Vice-Chairman Darrell Reneker — who admitted as much before calling on Treasurer Dan Galehouse for a report on our wealth. Treasurer Dan advised that we had started the evening with $384.60 (probably a record high for the club) but, after collecting dinner payments and “paying back a dollar owed to one member for whom I didn’t have change last May,” our new balance is $383.60. To which Darrell responded that in view of the current events in the stock market, we’d better be sure we have that in cash!
At which point our temporary chairman called on Program Chairman Sam Fielding-Russell for news about programs scheduled for the coming season. Sam had obviously done a greater job than any program chairman in years, as evidenced by his reporting nearly full docket by this first meeting of the season. There are only two blanks in the schedule, for which Sam said he had two suggestions during dinner:
October 27: Dr. Spyros Margetis, Kent State University (See above)
November 24: Dr. Bob Brown, Case Western Reserve University (whose specialty is energy), “What’s behind all these Headlines in the Newspaper About the Brain?”
January 26: Prof. John Portman, Kent State University (a bio-mechanicist), title to be announced.
February 23: Dr. Alan Gent, University of Akron, “Non-linear elasticity” — 100 Years of the Poynting Effect. [“If anybody here who knows what the Poynting Effect is,” Sam cautioned, “be quiet, and we’ll listen to Alan in February.”
March 23: Open at the time of the meeting; but since, Sam advises that Jonah Kirszenberg has been successful in getting Scott Graham from NASA as speaker Dr. Graham is NASA Glenn’s Launch Systems Project Office and will be speaking on “The Ares Launch Vehicle: Access to the Future.”
April 27: Dr. Owen Lovejoy, Kent State University, who is in the Department of Anthropology; he will be talking about physical anthropology, title to be announced.
May 18: Open, but “we are trying to sign NASA speaker, who will be talking either on NASA security, or on the Hubble Telescope.” Your secretary is hoping hard for the latter.
Charlie Wilson was then called upon to introduce our speaker, Dr. Jutta Luettmar-Strathmann, Associate Professor of Physics, the University of Akron, who then spoke to us on “Liquid Mixtures in Temperature Gradients — From the Prebiotic Ocean to Thin Layers of Polymer Blends.” What followed was a beautifully documented presentation of what might have come before the content of our 2005 speaker, Randall Mitchell’s exposition of “The Facts of Evolution.” It was the first time any of us have heard a hypothesis that carried hints of how life might have spontaneously begun on this planet.
Our speaker began by introducing Alolph Fick’s “Law of Diffusion,” which describes mass flow in liquids due to concentration difference, which was empirically demonstrated by Carl Ludwig (they were both 19th century German scientists). Ludwig’s experiment consisted of connecting two side-by-side flasks containing different concentrations of NaSO4 joined by a glass U-tube. Ludwig measured the diffusion of the concentration between the static flasks.
Meanwhile, Charles Soret, a mathematician and physicist, was measuring the effect of temperature on dilute solutions of salts in water by filling tubes with a liquid having a uniform concentration of salts from top to bottom, and then heating the top. He found that if you wait long enough (he waited 56 days), the salt becomes more concentrated in the cold part of the tube. His conclusion was that a temperature gradient applied to a fluid mixture generally induces net mass flows, which lead to the formation of concentration gradients. In quiescent mixtures, the effect is known as thermal diffusion or the “Ludwig-Soret effect,” As a mathematician, Soret quantified the phenomenon with an array of differential equations presented by our speaker, which are beyond the fonts available in this Macintosh (and probably this brain).
In conjunction with convective flow, it turns out that thermal diffusion becomes a powerful separation process that affects natural processes under geological conditions. Thermal diffusion is well known today to affect the partitioning of crude oil components in oil fields, and is also currently being investigated in the context of carbon sequestration; and very recently, a mechanism driven solely by a temperature gradient has been proposed to “solve the concentration problem associated with the origin of life. According to this proposal, proto-biological molecules become accumulated so strongly in pore systems associated with submarine hydrothermal vents that their concentration becomes sufficient to allow the spontaneous synthesis of complex biological molecules.
There is a mountain range on the ocean floor, the “Atlantis Massif,” in which there are carbonate “chimneys” rising from thermal vents, which create an ideal environment for the Ludwig-Soret effect. Called the “Lost City,” (by the exploratory group that group that named their research craft “Atlantis”), these structures have a hot interior surrounded by a cold exterior, with a 30-degree Kelvin delta T between them. This supplies the energy to move concentration masses, “writing patterns in polymer islands,” permitting the spontaneous synthesis of complex biological molecules. In living organisms with typically very high concentrations of large organic molecules in their cells, mechanisms like these are how other organic compounds (nutrients, enzymes, hormones, waste products) are transferred across cellular membranes.
Jutta described some of the details of her own work, and she cited a number of practical 21st century industrial uses that have been developed from Ludwig-Soret research: the analysis of liquid mixtures, the blending of nearly immiscible polymers, thermal field flow fractionation and distribution of crude components in oil fields, as well as the large-scale isolation of isotopes in the gas phase. But these advances pale in significance compared to the phenomenon — the event — that may have occurred between 2.8 and 4 billion years ago in the mid-Atlantic Ocean’s Lost City.
Meeting Announcement: MONDAY, October 27, 2008 - TANGIER, 6:00 PM
Speaker for our October meeting will be Dr. Spiros Margetis Associate Professor of Physics, Kent State University, Director of the Center for Nuclear Research — whose current activity involves collisions of heavy nuclei at ultra-relativistic energies, which offer unique opportunities to study the behavior of nuclear matter under extreme conditions of temperature and density. His research is currently carried on at the CERN Super Proton Synchrotron (SPS) in Geneva, as well as at the Relativistic Heavy Ion Collider on Long Island. The title of his presentation is:
A TRILLION DEGREES IN THE SHADE
He explains that the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven Lab, in Long Island, NY has been colliding heavy ion beams (of gold nuclei) for eight years, and in some experiments the nuclear matter is heated to about a trillion degrees (scale doesn't matter much at such temperatures). Such matter existed only ten microseconds after the Big Bang that brought the Universe into existence. He plans to give an update on important and oftentimes surprising results from the STAR experiment, one of the two experiments still in operation at RHIC.
Minutes, October 27, 2008
Returning after conducting a seminar last month at Georgia Tech and sort of apologizing (“I hate to say this but I had a better offer: they actually paid for my dinner!”) for being absent for the first time in the dozen years that he has been our leader, Chairman Ernst von Meerwall began by welcoming visitor Michael Pliska, a guest of Bob Erdman.
He then called on Treasurer Dan Galehouse for his customary chore. Dr. Dan advised that we had begun the evening with a balance of $383.60 (characterized by Chairman Ernst as “an unconscionable amount of money to keep as cash in a box”), which was why, in an effort to reduce it, Dan had charged us only $18 for dinner this evening. This, he said, should drop the balance to 355.60. But such was not to be the case! Frustrating our treasurer’s frugality, our Tangier host, it developed (after feeding us an excellent repast of half a chicken apiece), had also knocked a dollar off the price, resulting in a final balance of $386.60, plus a student fund remainder of $54. In his subsequent reluctant correction, our treasurer assures us (doubtless with a sigh of relief) that “The polyethylene-polypropylene box checks.”
Next, we heard from Program Chair Sam Fielding-Russell, who was pleased to announce that for our March 23rd meeting next year, Jonah Kirszenberg has been successful in getting Scott Graham from NASA Glenn’s Launch Systems Project Office for our speaker. Dr. Graham is and will be speaking on “The Ares Launch Vehicle: Access to the Future.”
After which Ernst advised that – again thanks to our Webmaster Jonah’s spending a significant part of his summer working with the University of Akron – our club’s website is back in business, prompting your secretary to explain (after thanking the membership for putting up with his e-mail experiments) that henceforth the Newsletter will appear as a complete single document of the announcement plus minutes, but with a URL to our website for a more readable copy.
At which point Chairman Ernst introduced our speaker, Prof. Spiros Margetis of the University of Akron, Director of the Center for Nuclear Research – whose current activity involves collisions of heavy nuclei at ultra-relativistic energies. His research is carried on at the CERN Super Proton Synchrotron (SPS) in Geneva, as well as at the Relativistic Heavy Ion Collider on Long Island. He last spoke to us in April of 2002. Our chairman said that he thinks of him as “an extreme nuclear physicist.” The title of his presentation was “A Trillion Degrees in the Shade.”
Underscoring Ernst’s characterization and the title of our speaker’s talk, the striking image that filled the screen during dinner was of a signal event: a single nucleus being impacted and exploded into 4000 separate tracks. And yes, the local temperature at the time really was about a trillion degrees K. It was the first slide of his Power Point presentation, all of which is accessible at either http://phys.kent.edu/~margetis/talks/Akron-2008.ppt or http://phys.kent.edu/~margetis/talks/Akron-2008.pdf
Warning: These take a considerable time (e.g. 15-20 minutes) to download.
At the Relativistic Heavy Ion Collider on Long Island, our speaker explained (quoting Nobel Laureate T. H. Lee in 1975), “In high-energy physics . . . we distribute higher and higher amounts of energy into a region with smaller and smaller dimensions.” This brings nucleons as close as possible, he said. As the temperature rises, the strong force gets weaker, and quarks (or “partons”) are free to move around, with the creation of pions – ultimately confining subatomic particles so tightly that the result is a phase transition, which produces “hydronic matter,” a quark-gluon plasma. In the process, the density has increased enormously.
We saw a graph of temperature vs. density that flattens at 1012 K – which, Dr. Margetis suggested, not only shows what happens in the Relativistic Heavy Ion Collider, but also represents the state of our universe a millionth of a second after the beginning of the Big Bang. When two gold ions collide in the RHIC a “Little Bang” occurs, producing an initial layer of what might be described as a highly-confined quantum fluid at a trillion degrees, having concentric pressure gradients and non-zero viscosities (the sort of thing we have in a black hole, our speaker said). At such temperatures, we actually see e=mc2 in action. The fluid undergoes a “chemical freeze” to become a hadron gas as it expands.
Our speaker showed us some details of the hardware at the RHIC facility on Long Island: an underground tunnel multiple stories in diameter, laid out in a circle about a mile in circumference. The giant conduit is surrounded by deflecting and focusing magnets that consume several megawatts of power. It tapers down to a much “smaller” detector section (on which a photo of a worker looked like an ant on a stovepipe). The architecture of the assembly resembles two enormous hoses with their nozzles joined facing one another.
The particles traveling around the circle accelerate, reaching 99.99% of the speed of light before smashing together. (That of the new CERN Super Proton Synchrotron in Geneva is 99.9999% of c.) At the RHIC facility we saw bubble-chamber tracks of the particles that are produced in successive billionths of a second during and after the collisions. An array of cascaded computers that are fed dozens of varieties of measurements, sorts out deuterons, protons, kaons, pions, and electrons. “Average” data are calculated from the multiple results.
After going through some of the mathematics associated with Bjorken’s relativistic hydrodynamics model, our speaker followed with a series of animated Power Point images in which he depicted the geometry of heavy ion collisions, elliptic flow in ultra-cold Fermi gas, followed by what for this secretary, were a series of increasingly arcane slides depicting results obtained on such subjects as energy density, time evolution at finite impact parameter “b,” resulting azimuthal distribution from central collision, azimuthal entropy of leading hadrons (which, Dr. Margetis says, show detailed agreements with the hydrodynamic model), viscosity and the perfect fluid, energy loss in Au + Au collisions, a plot of quark mass vs. Higgs quark mass, heavy “flavor,” leading hadron suppression, elliptic flow saturation (even with strange mesons and baryons), disappearance of any side-jets in Au + Au collisions and suppression of jets on the far side, leading to the conclusion that in central Au + Au collisions, hadrons are suppressed and back-to-back jets have disappeared – a result different from that of angular collisions. Some of these results suggest possible effects of multiple dimensions at these relativistic speeds.
The next step in RHIC research is what is called the Gamma-jet: Golden probe of CCD energy loss. It will cost about $50 million. For this engineer, Dr. Margetis’s presentation offered a glimpse into a whole new world of physics.
Meeting Announcement: MONDAY, November 24, 2008 - TANGIER, 6:00 PM
Speaker for our November meeting will be Dr. Robert Brown, Institute Professor of Physics at Case Western Reserve University, who received the Robert Foster Cherry Award for Great Teaching from Baylor University in 2005. Dr. Brown’ specialty is energy. But the subject of his talk is:
WHAT’S BEHIND ALL THOSE NEWSPAPER HEADLINES
ABOUT THE BRAIN?
Answer: It’s MRI. As he explains, with a reported 70 million scans made each year and the frequent news articles on what we are learning about our brain and how we think, magnetic resonance imaging (MRI) has become a major clinical and research phenomenon. Dr. Brown plans to discuss:
“1) A review of MRI basics; 2) The next Nobel Prize in MRI, and why MRI now is so important in the neuroscience world; 3) A new lie detector, and why some day we won't need to give any more classroom exams[!]; and 4) the latest work on making MRI quieter so as to reduce [what your secretary can attest is] some serious background [noise!] during brain imaging.”
Minutes, November 24, 2008
Our last meeting of the year attracted a welcome number of first-time visitors. Tom Brooker introduced Peter and Theresa Tandy; Peter is Professor of Physics at Kent State University; Theresa raises and shows champion poodles, Stu Clary’s guest was Dale Mugler, and Charlie Wilson invited Dick Wright who has recently retired from his own company. Dave Fielder introduced is wife, Sarah Wright and Dennis Feld introduced his wife, Barbara. Our student guest was Adam Koncz, who is a physics major at the University of Akron. When Chairman Ernst von Meerwall asked him how he heard about the club’s program, he said he found it on the Physics Club’s Website! He’s the first that we know about – too bad Webmaster John/Jonah couldn’t make it.
Ernst then turned to our sedulous, indefatigable treasurer, Dan Galehouse (who had been delayed by a flat tire in this, the former the rubber capital of the world!) for an assessment of “how broke we are.” Dan advised that we had started the evening with the (uncomfortably large) sum of $386.60 (plus an unexplained extra dollar), but that by charging only $17 for dinner, the amount should be trimmed down to $377.60 by the end of the evening. However, when the meeting had adjourned, it turned out that two diners had forgotten to pay, so the net ended up at the more comfortable level of $341.66 plus the student fund.
Then called upon, Program Chairman Sam Fielding-Russell (who gave us a complete calendar last month – see previous Newsletter) advised that the only slot open for the new year is in May, for which date he is trying to get a speaker from NASA to speak on the Hubble Telescope. At which point Ernst introduced our speaker, Dr. Robert Brown, Institute Professor of Physics at Case Western Reserve University, who received the Robert Foster Cherry Award for Great Teaching from Baylor University in 2005. Dr. Brown has spoken to us twice before: in March of 1999 (on baseball statistics!), and in January, 2004 he first introduced us to the subject of MRI – his subject for the evening.
Our speaker explained that in, 1982, a former student who worked for a company that manufactured MRI equipment asked him work on some problems with him – after which, he said, “MRI took over my life.” He has since published, with three coauthors, a textbook on the subject, and is still amazed at how MRI is continuing to make major strides in anatomical imaging, not only in the brain (e.g., tumors, motor skills, cognitive functions, Alzheimer’s) but also as an incredible tool for diagnosis of disease (images of the heart, arteries, sports injuries, arthritis, epilepsy) – “you name it, we’ll connect it to magnetic resonance.”
Since, he said, his students insisted he open a lecture with a joke, they had prepared one for him for the occasion – Question: Why can’t two melons run away to get married? Answer: Because they cantaloupe. Relevance: In Japan, watermelons are so expensive ($30 apiece), that they have developed a machine for imaging the insides so they won’t have to cut it open to show that it contains no voids or overripe spots. [Joke Rating: Puns are better spoken than printed,]
Dr. Brown added a funnier contribution by a Cleveland cab driver several years ago when he had organized a workshop on MRI – an assemblage that attracted scientists from all over the world, and which contributed to the local cab drivers getting pretty savvy. As one of the visitors announced his destination, “Oh,” the cabby had responded, “you’ve come to that Magnetic Renaissance!” It really has been a continuing renaissance, our speaker observed, for 26 years.
In MRI we are not just searching for densities, like X-rays, he explained. The power of MRI is that one can measure different tissue properties, the proton density, as well as molecular structure (although last is less important than in NMR). X-ray tubes and ultrasound transducers project a single beam. MRI systems immerse the patient in very large (as well as small) magnetic fields. And MRI images can be displayed in 3-D. They reveal pictures of hydrogen nuclei in a given “slice.” (“Our bodies are, after all, mainly water – with some fat.”) And the reason we don’t get pictures from our body’s O16 and C12 is that neither of these atoms has any net spin, so they don’t precess in a magnetic field.
It takes three fields to achieve 3-D images. The way MRI works is: 1) We immerse a patient in a strong magnetic field created by a giant superconducting solenoid that completely surrounds him – a field 10,000 times as strong as the earth’s magnetic field; 2) we add a small, oscillating radio-frequency magnetic field tuned to the precession frequency of the protons in the strong field; 3) to create an image, we add small non-uniform (gradient) magnetic fields; 4) we then measure the protons’ (hence the body’s) response to these three magnetic fields. Although the assemblage of concentric coils is surrounded by a heavy magnetic shield, we nevertheless, saw a slide of a steel hospital cart that had been lifted off the floor by the strong field and stuck into the end of one machine.
Each proton, Dr. Brown explained, is like a small, spinning magnet. It behaves like a spinning toy top under the influence of gravity, which causes it to tip, or precess, instead of falling. The analogue to the gravitational field, in the case of the hydrogen nucleus, is the strong magnetic field. As the proton precesses, its little magnetic dipole field precesses too. It is this field that induces an EMF in the nearby detector coil, the fourth solenoid surrounding the patient. The applied magnetic field gradients, turned on and off hundreds of times per second in three directions, make it possible to localize the protons and make imaging possible. It is, incidentally, the effect of these flickering gradient fields on adjacent metal structures that creates the deafening (130 db) noise that a patient is subjected to.
Another planted question inquired, “If we are talking about a single proton, quantum mechanics tells us that its spin and spin energy are quantized. Is the picture of a precessing spin with a continuous tilt angle really appropriate?” The answer is that we are talking about trillions of protons. When huge numbers of protons are precessing together in synch to make one big spin, the classical picture is OK! Thus, we can readily detect the precession and its frequency from the millivolts generated in the detector coil.
Each time the gradient field is turned off (hundreds of times a second), a resultant pulse is detected, thus permitting examination of the tissue one slice at a time. For static images, a resolution of a fraction if a millimeter can be achieved. In functional MRI (fMRI), successive images every two seconds for five minutes produce a low-resolution (3 mm) “motion picture.” This makes it possible to examine the magnetic effect on blood, and brain activity associated with blood flow in brain functioning. Oxygenated blood gives a stronger signal than deoxygenated blood (less dephasing). This permits imaging of brain activity, such as that associated with motor skills and cognitive activity.
In a recent fMRI experiment, 2500 brain images from 17 college students who had just fallen in love were analyzed. The volunteers had been shown a series of images that included beautiful landscapes or other pleasant scenes that inspired feelings of admiration or even affection. But when they were shown a picture of their new beloved, a totally different part of the brain was activated – the same site that is turned on by cocaine! So, our speaker suggested, “You can find out if she’s really in love with you.”
It follows that MRI can be a new, more sophisticated lie detector technology. Indeed, a firm in Tarzana, California, No Lie MRITM (http://www.noliemri.com), is now offering its services to lawyers, corporations, and the federal government, as well as individual customers. Since our meeting, our speaker has acknowledged receiving a website your secretary sent him containing an article in the November 8, New Yorker, entitled “Suffering Souls.” It describes the work of Dr. Kent Kiehl, a research psychologist who uses MRI technology to scan volunteer prison inmates at the Western New Mexico Correction facility for signs of pyschopathy (defined as persons lacking any moral consciousness) in the hope of discovering a treatment. It can be read at http://stircrazyintexas.blogspot.com
(With sincere thanks to Editor Ernst!)