Akron Phy sics Club
Meeting Announcement: MONDAY, January 23, 2012 - TANGIER, 6:00 PM
Dr. Evalyn Gates, Executive Director and CEO of the Ceveland Museum of Natural History
will be speaking on:
Einstein's Telecope: The Hunt fo Dark Matter and Dark Energy in the Universe
Evalyn Gates is the Executive Director and CEO of the Cleveland Museum of Natural History. Before coming to the Museum in May, 2010, she was the Assistant Director of the Kavli Institute for Cosmological Physics and a Senior Research Associate in the Department of Astronomy and Astrophysics at the University of Chicago.
Her research focuses on various aspects of cosmology and particle astrophysics, from neutrinos to the cosmic microwave background. Most recently she has been working on various aspects of dark matter, and searching for ancient stellar fossils in the form of the oldest white dwarfs.
After receiving her Ph.D. in theoretical physics from Case Western Reserve University in 1990, Gates held postdoctoral fellowships at Yale University and the University of Chicago, and was a member of the theoretical astrophysics research group at Fermi National Accelerator Laboratory. She spent seven years at the Adler Planetarium and Astronomy Museum, initially as Director of Astronomy and then as Vice President for Science and Education.
Gates has a strong interest in addressing the under-representation of women and minorities in the physical sciences and has written several articles on the topic of women in physics. She is also committed to inviting individuals of all ages and backgrounds to explore the ideas and discoveries of current scientific research. Her first book, Einstein’s Telescope: The Hunt for Dark Matter and Dark Energy in the Universe, was published by W.W. Norton in February 2009.
Minutes, January 23, 2012
JANUARY 23 BUSINESS MEETING MINUTES:
We were honored to have Charlie Wilson's sons Will and Robb join us for the meeting. Will gave a nice speech saying how much Charlie enjoyed the Club, and how much it was a part of his life for many years. They bought boxes of books related to Physics that were selected from Charlie’s library. These were auctioned off, and brought in over $150. Many members of the Club enhanced their library thanks to Charlie’s family and his sons bringing the books to us. We thanked them with a round of applause.
Erdman has taken responsibility for Charlie’s duties, was also given a round of applause [thank you] and said he was well trained by Charlie. Erdman mentioned Science days on January 28 and February 11 for which professional Scientists, particularly Physicists are needed. A Physics table will be at the January 28 Science Fair, manned by Peter Palffy and Graduate students and Post-Docs from Kent State University.
Charles Lavan reviewed upcoming programs for the remainder of this club year, which are unchanged and listed on the web site. Plans are being formulated for next year, including two speakers already arranged and Will Jack, the High school student who developed a Fusion Reactor in his basement. On March 26 Dr. John Lucky from NASA Glenn will talk about algae blooms in western Lake Erie.
Jonah Kirszenberg has been handling the web site at physics.uakron.edu/APC. It can also be accessed through Google; type in Akron Physics Club. Archives going back over 10 years can also be accessed from the site. We gave Jonah a round of applause for his work on this. He is now starting to work on upgrading the site.
Treasurer Dan Galehouse reports that 29 people attended this meeting, including a student and the Speaker. The beginning balance was $244.45. Gross income from the book sale was an amazing $168, some of which was donation not tied to a book sale. Some of this money was used to fund the student dinner. In the end, the calculated balance and the counted balance agreed and we have $403.45 in the Tupperware treasury.
Chairman Ernst von Meerwall introduced our speaker, Dr. Evalyn Gates. She is a theoretical Physicist, got her Doctorate at Case Western Reserve University. Had PostDocs at Yale and University of Chicago. She worked at Fermi Lab for many years, then moved into educational posts at the Adler Planetarium, and is now Chair and CEO of the Cleveland Natural History Museum. She has been working in cosmology for the last 20 years or so.
One of her recent projects was a Smart Home designed by Physicists, now located in University Circle. It is a 2500-square-foot 2-story energy-efficient passive home, and brochures were available at the meeting.
NOTES ON DR. GATES' PRESENTATION:
Dr. Gates' career did not start in cosmology. She started in particle physics, got involved in particle astrophysics, and has been in cosmology for the last 20 years. She passed out the bottom of a wine glass, which can be used as a gravitational lens, which can make a ring of light out of a point source. She challenged us to find a way to get 4 images of a point source.
Unlike 20 years ago, particle physics and cosmology now work together on understanding the universe. Most of what the universe is made of is 'dark matter', that is not material which interacts with light. Fritz Witke in the 1930s first found this effect in a cluster of galaxies were moving around 2 million miles or more per hour, which was completely inconsistent with gravitational principles for the know mass of the star.
90% of the mass in our galaxy and over 1000 others that we know of is dark matter. The effect of dark matter is that the observed speed of a body around a star would indicate that the body would have been flung out the system long ago, unless there is some additional attractive force holding them in the system. An added mass in the star would provide such an attractive force. The comment that 90% of mass in a galaxy is dark matter means that the observed mass is 1/10 of the apparent mass [10% observable matter, 90% dark matter].
Barionic matter is everything we have seen or detected. This comprises only 5% of the matter in the universe. Looking at the census of the universe viewed in many ways, including cosmic microwave background, big-bang nuclear synthesis, supernovi, analysis of density fluctuations, primordial gas clouds and temperature of matter in the universe, it very consistently appears that the universe is made up of 23% dark matter, 73% dark energy, and less than 5% or less barionic matter. The dark energy is not convertible to mass and is not coming from a particular source. It is everywhere. For the last 5 billion years has been the predominant energy source in the universe, and has caused expansion of the universe. It is cold [non-relativistic at the time it was formed.] This understanding now leads to good agreement that the universe is 13.7 billion years old. A few years ago, it was thought to be "10 to 20 billion years old". 20 Years from now we likely will have detected dark matter and be exploring its properties.
It is not clear what all the types of dark matter are in the universe, but one is called Weakly Interacting Massive Particles [WIMPS]. These have not been detected.
In 1998 it was shown that the universe is not only expanding, but expanding at an increasing rate. The implications are that gravity is no longer in control; 73% of the energy is dark energy, and for the last 5 billion years it has been expanding at an increasing rate. One possibility considered was an error in the cosmological constant, which is the background energy of the universe. But calculations indicate this would be 120 orders of magnitude larger than the present value used for the cosmological constant.
How do we explore this new view of the universe that does not seem to make sense? Einstein may have left a blueprint for this investigation. In 1912, he contacted a colleague, Irwin Freimlich in Berlin. He told him he had a new theory of gravity. The mass of the sun would deflect the light from a star as the light passed near the sun. This could be observed during a solar eclipse. Freimlich put together a team of astronomers and went to the Crimea for the solar eclipse in August 1914, the time of the outbreak of World War One. The Astronomical team and their equipment were captured by the Russians, and the experiment was not done. In 1919, after Einstein completed his theory of relativity, including the curvature of space, Sir Arthur Eddington measured the deflection of light of stars near the sun. Einstein's essential prediction was that mass will deflect a light beam from a further star. This is the basis of gravitational lensing, which today is used to detect dark mass. If perfectly aligned, a point source
can appear as a ring, or multiple points, which may be delayed by days. This has been used to probe stars over 20 light years away. It may be used to map the dark matter in the universe. Such maps could lead to an understanding of dark energy. Dark energy works to increase the distance to a red shift and it expands space-time, and slows expansion. Gravitational lensing is sensitive to both of these effects, thus we can use it to look at different times, and better understand dark energy. Gravitational lensing is the best hope we have today to better understand dark energy.
We thanked Dr. Gates and she answered a few questions, related to the age of dark energy, how acceleration of the universe is measured and how reconstructions are developed. In response to a question, she clarified that black holes do not seem to be related to dark energy; since they involve barionic matter.
The figures in the talk are not yet available as of Feb. 16, but Dr. Gates plans to put the presentation up on her web site soon. If you want to see the slides in the future, view her site at http://einsteinstelescope.com .
Bob Erdman, Secretary, Feb. 16, 2012
Meeting Announcement: MONDAY, February 27, 2012 - TANGIER, 6:00 PM
Dr. Gary Hamed, Professor of Polymer Science focusing on Rubber Science and Technology, University of Akron
will be speaking on:
Tearing of Natural Rubber Vulcanizates
Natural rubber (NR) strain-crystallizes and this imparts high tear resistance to its vulcanizates. This presentation will focus on the effect of carbon black on strain-crystallization and tearing of NR.
Dr. Hamed Holds a B.S. and M.S. in Chemical Engineering from Cornell University and a PhD. Polymer Science from the University of Akron. After four years at Firestone Central Research, he became a professor at the University of Akron in science and technology of rubber. He has been there for 32 years.
Minutes, February 27, 2012
Report by Secretary Bob Erdman on the February 27th meeting:
Chairman Ernst introduced his wife Marianne von Meerwall, Brigitte Hirst, Robert Hirst's wife, Peter Henriksen and our speaker Gary Hamed, all of whom have not been with us for awhile. He explained the low attendance due to at least one of our members attending the APS meeting this week, some of our members beings sick, and others not yet returned from Florida, where they stay for the winter.
Treasurer's Report: Tonight we have 12 paying members, meaning that we lost $6.00. Thus the original balance of $403.45 is reduced to $397.45. Secretary Erdman apologized for incorrectly referring to our plastic bank as a Tupperware bank. It a polypropylene box, and I'll refer to it in the future as the polypropylene Bank.
Erdman reported on upcoming meetings: In April, we will have Dr. Andrew Resnick of Cleveland State University speaking on the Biofluid dynamics and the physiological role of the primary cilium. Charles Lavan is arranging speakers for next year, and we'll hear more about this next month. It was also mentioned that the Science fairs always need judges, including and particularly Physicists, since we have a wide knowledge. The Ohio Academy of Sciences website lists all Science Fairs.
Chair Ernst mentioned that the May meeting will not be held here. We'll hear more on this next month. This is also the time of year when officers for the following year are nominated. While the present officers are willing to do their jobs, if you attend regularly and are interested contact Ernst. We need some new blood in the officer ranks.
Ernst introduced Gary Hamed, our speaker: He has a BS and MS in Chemical Engineering from Cornell, and got his Doctorate at University of Akron, under Alan Gent, a member of our club. Gary in addition to being an expert on the topic for tonight, has studied the history of physics, and we may have him back in the future for such a discussion.
NOTES ON DR. HAMED'S PRESENTATION:
This presentation is on tearing of vulcanized natural rubber. Gary showed us a roughly rectangular rubber sample, with a cut in one side. Natural rubber comes from trees, tapped from a tree much like gathering maple syrup. It is cured using sulfur. A very common form of rubber is cis-1,4-polyisoprene. It can be crystallized, by stretching or cooling to about -25C.
Two tests are required by the US government to determine durability of a tire. A high stress area of tires is near the belt edge. Carbon black filled natural rubber is used in this area of the tire. The carbon black is a fine powder, tens of nanometers diameter. This is a likely area for tire failure to begin, since there is a "crack" at the belt edge by design. The two tests to make it fail are to increase the speed with a fixed load, or to hold speed constant and increase the load until failure occurs. Too low pressure in the tire can cause earlier failure due to the heat created by higher deflection when pressure is low.
The rubber samples are put under tensile stress, and the crack grows across the sample. Log plots are made of the stress required to break [snap] the sample vs. the initial length of the tear [sample cut or crack length]. A 0.1mm cut causes a drop in strength of a factor of 2. A discontinuity occurs between no crack and the 0.1mm initial cut in pure rubber with no filler. Another discontinuity occurs at large initial crack lengths. Above some initial crack length, the sample will break at less than 240% elongation; at lower initial crack lengths, it exceeds 510%. In the latter, bulk crystallization occurs; no crystallization occurs in those that break below 240%. Failure between these two values of elongation do not occur.
As stress is applied, at some point the crack grows in different directions and permits higher tensile strength [by about a factor of 3] before the catastrophic crack grows, which causes the test sample to break. This is because of anisotropy created when under strain, in which case the strength perpendicular to fibrils is much stronger that strength parallel to the fibrils. Thus it is no longer an amorphous material.
If a little very fine carbon black is added, the material gets weaker. If a lot of carbon black is added, it gets stronger. It gets weaker because the carbon black interferes with nucleation [under 12phr, the measure of carbon black concentration]. Under strain, the rubber stretches a lot, but the carbon black does not. So there are regions of high and low strain. High strain promotes crystallization [at over 50phr]. At 14 to 15phr percolation occurs at which point the carbon black forms its own phase within the rubber. This is essentially a physical, not a chemical cross-linking. Above this point, crystallization occurs and strength is higher. Below percolation crystallization does not occur. Also, low-strain stiffness and electrical conductivity dramatically change at the concentration at which percolation occurs.
Tear testing, as Dr. Hamed described, is a more discriminatory test than a simple tensile strength test, because there is a defined anisotropy at the crack tip, due to a continuous network carbon black forming at the tip. The 14 to 15phr occurrence of percolation is for a coarseness of 115. Percolation occurs at higher concentrations if coarser carbon black is used.
We thanked Dr. Hamed for his talk and asked questions about the impact of mixing techniques, and the 3 ways of observing percolation.
Bob Erdman, Secretary
Meeting Announcement: MONDAY, March 26, 2012 - TANGIER, 6:00 PM
Dr. John D. Lekki, NASA Glen Research Laboratory
will be speaking on:
his development of an airborne Hyperspectral pushbroom imaging sensor that he uses to study the growth of cyanobacterial algae in Lake Erie
The National Aeronautics and Space Administration’s (NASA) Glenn Research Center and the National Oceanic and Atmospheric Administration’s (NOAA) Great Lakes Environmental Research Laboratory have collaborated to utilize an airborne hyperspectral imaging sensor suite to monitor algal blooms in the western basin of Lake Erie and also Saginaw Bay in Lake Huron.
Bloom development can be a very dynamic process, normally forming, spreading, and disappearing within days to weeks during mid to late summer. They are a concern for human health, fish and wildlife because they can contain blue green toxic algae. This situation is well suited for aircraft based monitoring because the blooms can be so dynamic and they can spread over a large area. A second generation custom designed hyperspectral imager installed in NASA aircraft has been used to obtain data of multiple areas in the western basin of Lake Erie and Saginaw Bay. Water samples have been taken in these same areas concurrently by NOAA and the Environmental Protection Agency (EPA). Analysis of this data and the capability of the airborne hyperspectral imager to detect low concentrations of blue green algae will be presented. Some other work that will be presented includes the airborne study of the Guanica dry forest and La Parguera coral reefs in Puerto Rico.
John Lekki is a Senior Researcher in Optical Instrumentation at NASA Glenn Research Center. His research interests include: Hyperspectral Remote Sensing, Integrated Vehicle Health Management, Quantum Information Systems, and Fiber Optic Sensors. In 2006, He initiated a joint NASA NOAA research project to develop and utilize an airborne hyperspectral imager to remotely identify harmful algal blooms in the Great Lakes. The original goal of this program was to develop a small, lightweight and low power hyperspectral imager appropriate for use on a 40kg Unmanned Aerial Vehicle. He has led a team of researchers, engineers and technicians to develop and deploy two generations of small hyperspectral imaging systems. These have been successfully deployed on manned aircraft for 30 flights during field work in 2006, 2007, 2009 and 2010.
Previously, Dr. Lekki has also been the Principal Investigator for the Quantum Sensing and Communications project for micro robotics. In this project the capability of transmitting information over 70 meters of free space using atto-Watts of radiated power/ bit in an optically noisy environment was demonstrated. He has a Ph.D. from Michigan State University in Electrical Engineering in 2008 and also has a M.S from Cleveland State University in Physics and B.S. in Electrical Engineering from Michigan State University in 1993. Between 1993 and 1998 he served as a Lead payload experiment integration engineer at Kennedy Space Center for United States Microgravity Payload (USMP) 4 mission and the Shuttle Radar Topography mission.
Minutes, March 26, 2012
Report by Secretary Bob Erdman on the March 26th meeting:
Treasurer's Report: Tonight we have 13 paying members, meaning that we lost $5.00. Thus the original balance of $397.45 in the polypropylene bank is reduced to $392.45. The actual balance agrees with this figure.
Charles Lavan reported on upcoming meetings: On April 23, we will have Dr. Andrew Resnick of Cleveland State University speaking on "Mechanosensation and the Primary Cilium: When push becomes shove". His work is at the border between biology and physics. He is on the staffs of Cleveland Clinic, University Hospitals and Cleveland State. [The Announcement of the April meeting will contain more info on this.]
In May, we learned tonight that there will be a very large crowd at the Tangier on the originally scheduled date of May 21 [May 28, the 4th Monday, is a holiday, so we chose May21]. Originally this was not a problem, since we were planning to meet at the Fairlawn Country Club. But we then learned that they do not function on Mondays. Tangier clearly recommended that we NOT meet there on May 21, due to a large crowd for a football rally, making very it difficult to get in and park. The Torch group will be meeting at the Tangier on June 4, which was suggested by Tangier. We agreed that June 4 will be the meeting date. Tangier was very glad to hear this. Charles Lavan will contact Chris Martin, the scheduled speaker to see if he is willing to speak on June 4 instead of May 21. It is not clear that he will speak on June 4.
Charles Lavan has arranged 4 speakers for next year, beginning with Will Jack in September. Dr. Colin Drummond from Case, from NASA Glenn and Goodyear will speak to us in October. Dr. Houck will update us on the Mercury project. He is looking for a woman speaker. Ernst will contact some of the 8 new staff additions in the Polymer area at Akron as potential speakers.
Chair Ernst mentioned that this is also the time of year when officers for the following year are nominated. While the present officers are willing to do their jobs, if you attend regularly or have a good idea for nominee who would be willing to serve, contact Ernst. We need some new blood in the officer ranks. See his notice at the end of these minutes. We want to have nominations in place by the April meeting.
He also mentioned that Alan Gent, a long-time member of the club is gravely ill with cancer and has not been given long to live.
April 13 and 14 is the meeting of the Ohio Section of the APS in Columbus.
Erdman mentioned that there is a coaching/mentoring session the morning of April 14 at 9:00 at the Polymer building at Akron University for students going to the State Science Fair. Physics professionals are always welcome because of our breadth of knowledge.
Ernst introduced Dr. John Lekki, our speaker: He has a BS in Electrical Engineering from Michigan State University, an MS from Cleveland State University, and in 2008 a Doctorate from Michigan State University in electrical Engineering. He has focused on spectroscopy and arial imaging to learn about various bodies of water. His work on this was done in collaboration with many people at NASA Glenn and in Michigan, as well as some collaborators at University of Toledo, some in Puerto Rico and in Alaska.
NOTES ON DR. LEKKI'S PRESENTATION:
The focus of this talk is algal blooms that were prevalent in the 1970s. They then died out and started to come back strongly in 1995. The biggest concern is microsystin, which is toxic and can be a problem in water systems. Hyperspectral imaging looks at specific frequencies to form the image, which can identify the type of algae. Sediment from the Maumee River and the St. Clair River from Detroit empty into Lake Erie at the west end of the lake. They can readily change concentration pattern in the case of a storm on the lake.
Many satellites pass over the area of the lake of interest, but there are not many flights with resolution of 30 meters which they would like to have to track the migration of the algal bloom. In 2006 they built a small package that simply bolts on the side of an aircraft. An improved version was built and is still in use. Other requirements were that the imaging system be fast and work in low light levels corresponding to the low reflectivity of water [6%]. It operates in the visible and near-infrared wavelengths [400nm to 900nm wavelength]. has small size, only 3kg weight and uses only 35watts of power.
The hyperspectral imagers have many more narrow frequency bands than multispectral imaging systems, which have a few wide frequency bands [256 narrow bands vs. 4-8 wide bands.] Signal-to-noise ratio of the final version is about 1000:1. Spectral resolution is about 1nm. Both attitude of the aircraft and the location, as determined by GPS sensors are recorded to map the algal blooms. Each species of algae has its own reflectance signature. Chlorophyll and phycocyanin reflectance are two of the key parameters they look for. These are compared and the concentration of the phycocyanin toxin is determined, and distinguished from chlorophyll.
When taking these measurements from a boat, 2 samples are used to determine concentration. Sometimes these vary by 36%. Often the microsystis toxin is in a very narrow stripe, on the order of 10-15 meters wide, so the 7-meter boat can easily drift in and out of the narrow stripe. The aerial observations had resolution of 2 meters, vs. 30 meters with other techniques, which easily miss the narrow strip of concentration. By comparing reflectivity of phycoplankton and phycosystis, they can distinguish between phycosystis concentrations of 20-30 micrograms/liter and a 10 microgram/liter concentration; both are well below acceptable limits for public water. This cannot be done using the other imaging techniques.
I n Puerto Rico, the objective is to determine the level of toxins affecting the coral reef. This work involved some 15 students involved with the data taking and spectral analysis. Another location was in Barrow Alaska. In spite of the low light levels, they were able to get valid data.
We thanked Dr. Lekki for his talk and asked a few questions about other lakes they plan to investigate, speed with which the algae grows, levels below the surface at which concentrations can be determined, types of sensors used, other uses of the technique, and he discussed plans for doing some fluorescence work.
Bob Erdman, Secretary
Meeting Announcement: MONDAY, April 23, 2012 - TANGIER, 6:00 PM
Dr. Andrew Resnick, Assistant Professor of Physics, Cleveland State University
will be speaking on:
Mechanosensation and the Primary Cilium: When push comes to shove
Our research is a true blend of Physics and Biology. We study how physical forces, principally fluid flow, act as a stimulus on epithelial tissue via the primary cilium. We subject cultured tissue to physical stimuli- either fluid flow or optical trapping- and measure physiologically relevant readouts to better understand homeostasis and certain diseases; Autosomal Dominant Polycystic Kidney Disease (ADPKD) and hypertension, for example. We have shown that fluid flow can modify the cell cycle and have demonstrated physiologically relevant results in an immortalized cell line derived from the cortical collecting duct taken from a mouse kidney. Both recent results and current experiments will be discussed.
Dr. Resnick is an Assistant professor in the Department of Physics at Cleveland State University, and an Assistant Professor in the Department of Biology Geology and Environmental Science at Cleveland state University since 2009. He is on the Adjunct Staff in the Depatment of cell Biology at Cleveland Clinic Foundation, and an Assistant Adjunct Professor in the Department of Physiology and Biophysics at Case Western Reserve University. He got a B. S. in Physics from Rensselaer Polytechnic Institute in 1991, a Ph.D. in Physics at University of Alabama in Huntsville in 1997, and a degree in Physiology at Case Western Reserve University in 2004-2005. He was on the faculty of Case Western Rsserve University in the physiology and Biophysics Department from 2005 until 2009. Prior to 2005 he was at Nasa Glenn in the National Center for Microgravity, and stationed there working for Northrup Grumman as a Senior Scientist.
Minutes, April 23, 2012
APRIL 23 BUSINESS MEETING MINUTES:
Dr. Bill Landis of the Polymer Institute introduced some new people who work with him on the primary cilium: Robin Jacquet, Laboratory Manager; Jessica Kampenin, Post Doc in Dr. Landis' lab; and Mary Beth Wade, a Graduate Student in Integrated BioSciences at the University of Akron. They heard about the meeting through an announcement at an ACESS meeting. We were all pleased to see such a group visiting us. Chair von Meerwall mentioned that Bill Landis has been made a Fellow of The Microscopy Society of America for his outstanding work with microscopy to advance the knowledge of bone and cartilage development.
Don Wiff was not expected to be able to attend, but the storm warnings were cancelled so he did join us. Alan Gent has won the Inaugural Tire Technology Lifetime Achievement Award for lifetime achievements in the industry at a conference in Cologne Germany, and the Tan Sri Dr. B.C. Sekhar Inaugural Award, to be bestowed this summer. He is well enough to be working on two books. Also Dr. Darrell Reneker has been made a Distinguished Professor of Polymer Science.
Treasurer Dan Galehouse reports that are 15 paid attendees at this meeting, and the cost of the speaker's meal was $18, creating a net loss of $3 for this meeting, reducing the balance in the box of $292.45 to $289.45.
Our next meeting is June 4: Charles Lavan reported that Dr. Chris Martin of Oberlin, originally scheduled for May 21, will not be in town June 4, but is now scheduled for Nov. 26. On June 4, Dr. Richard Elliott from University of Akron will speak on Applied Thermodynamics for Nanoengineering in the 21st Century. Next fall we have Will Jack in September talking about his home-made fusion reactor, and in October we have Dr. Colin Drummond at Case Western Reserve University who will discuss his work on sensors. Charles is exploring many possibilities for other speakers next club year.
Chair Ernst brought up the officer election for next year: It was suggested years ago that if there are no new nominations, the present officers remain in office, by force if needed. There being no nominations, it was agreed by unanimous seconded motion that present officers remain in office "by force" if necessary, but all agreed to remain. Ernst will gladly accept nominations of people willing to be officers, by any means. The only requirement is that an officer attend many meetings, but it is not necessary to attend all meetings.
We had a discussion on declining attendance: It was suggested we contact those who have not been attending regularly regarding their reasons for lower attendance. Dr. Landis agreed to try to attend our July planning meeting. Posting announcements of meetings might also help, particularly for students. There is also a weekly email digest of University of Akron activities, one for students and one for faculty--perhaps we should get listed in these.
Chairman Ernst von Meerwall introduced our speaker, Dr. Andrew Resnick, of Cleveland State University. He got a physics degree from Rensselaer Polytechnic Institute in 1991, got his Ph.D. from University of Alabama in Huntsville in 1997, a degree in physiology at Case Western University in 2005, then worked at Northrop Grumman at NASA Glenn in the National Center for Microgravity and was on the faculty of Case Western Reserve University in the Physiology and Biophysics Department from 2005 to 2009. He is now an Assistant Professor in Physics and an Assistant professor in the Department of Biology, Geology and Environmental Science at Cleveland State University, as well as an Adjunct Staff in the Department of Cell Biology at Cleveland Clinic, and on the faculty of the Department of Physiology and Biophysics at Case Western Reserve University.
NOTES ON DR. RESNICK'S PRESENTATION:
Dr. Resnick's work is very interdisciplinary, at the intersection of biology and physics. An area that he worked in at NASA Glenn involved studies on bone mass of astronauts: They lose about 2% of bone mass per month in zero gravity. It is not known why this occurs, or how to prevent it. Bone loss is predominant in the pelvis and spine, and there is a gain in bone mass and the skull. Thus gravity affects bone development.
In zebra fish, which are transparent, experiments were done on the development of the heart, which starts out as a tube that bends around and becomes a complete heart. By putting magnetic beads in the heart, fluid flow to and from the heart can be controlled. Fluid flow affected the heart development. This is an example of how internal fluid flow in the body affects physiological development.
There are 3 types of cilia: Dozens or hundreds of motile cilia can be in a single cell. These occur in the airway, vasculature, and the central nervous system in the brain. These cilia actively "beat" to propel fluid, for example to keep the lungs sterile by moving mucus. There is only one sensory cilia per cell. Most of Dr. Resnick's work involves these cilia. The sensory cilia senses, but does not create fluid flow. Among other places, these are founds in the kidney. Nodal cilia appear in the early development of humans, for only a few hours. They propel the blastocyst in a spinning motion, that ultimately determines right and left sides of the body. If this sense is not developed properly, the arrangement of organs in the body can be in a mirror image of the normal structure [situs inversus].
Dr. Resnick used the motile cilia to illustrate the structure of a cilium. They are about 0.2 microns in diameter and 3-5 microns long. The structure is genetically identical to a bacterial flagellum. There are 9 microtubular doublets around the periphery of the cilium; motile cilia also have a pair in the center. These are used to transport protein up and down the cilium. The cilium begins to grow once a cell has completed the division process. Part of the cilium is inside the cell wall, and visible portion is the 3-5 micron "hair" protruding out of the cell.
His work is focused on kidney function. A human kidney is about the size of your fist. Each kidney processes about 50 gallons of fluid a day. About 25% of the blood from the heart goes through the kidney. The kidney maintains homeostasis, keeping salt, blood pressure, etc. stable, by returning most of the salt and water to the blood and taking out the urine components. It consists of about 1 million tubes. Each tube has a 30nm slit through which the fluid passes. As we age, the kidney may develop Polycystic Kidney Disease [PKD], which can happen beginning around age 50, causing the kidneys to grow. One important aspect of these studies are how fluid flows in the kidney. The tube walls are 1 cell thick, and are renewed every two weeks. If there is a malfunction and flow stops, the cilia no longer are bent with the flow. This triggers a progrowth repair mechanism. This occurs in PKD, causing the kidney to enlarge. There are also other diseases, called ciliopathies, that cause the cilia to malfunction.
Dr. Resnick's group grows their own cells on a suspended porous membrane that develops a top and bottom. Cells form a monolayer, and transport sodium from one side to the other in a current of about 10microamps per square cm. This current is a marker for the physiological state of the cell. Laminar vs. turbulent flow and other characteristics are studied. In turbulent flow, such as that created by plaque in an artery, the cilia do not bend with the flow, and the progrowth repair mechanism is engaged, causing the plaque to grow.
The Reynolds Number is the ratio of velocity to viscosity. A higher Reynolds number indicates velocity will continue after the stimulus is stopped, due to inertia from the velocity. A low Reynolds number indicates that motion does not continue after the stimulus is stopped due to relatively high viscosity, such as in a kidney where the Reynolds number is about 0.01.
When force is applied to a fluid, continuum mechanics are needed to describe the impact of the stress, using the Cauchy equations rather than F=ma and momentum conservation. Unlike solids, a stress creates a flow, not strain. When the applied force goes to zero the flow stops. Stress tensors are used to analyze the results of applied force. The stress creates stretch [in the cylindrical wall] or shear of a "cube" of fluid. This is analyzed using Poiseuille flow, which includes boundary condition of symmetry across the cross section of the cylinder, and a "no slip" assumption that there is no motion of the fluid at the edge of the cylinder, which is usually incorrect in practice.
Shaking the cell even at low frequencies affects both cilium length and sodium current transport. Cilia are very sensitive, reacting to stimuli just above thermal noise. When cell differentiation occurs, no cilium grows. Once the differentiation process [cell division] stops, the cilia grow. Changes in flow affect can affect differentiation. Many other tests have been done comparing actual behavior to predictions, such as exponential decay when porous cell walls are present, things which affect length of the cilium, the effects of various flow patterns and direction. Time-dependent flow is very difficult to analyze and measure, but this represents fertile ground for new experiments. Overall, it is becoming clear that flow sensing in organs and their sub-parts is a necessary condition for normal physiological operation, and when flow ceases or flow sensing malfunctions, the cells experience uncontrolled proliferation, leading to the chronic inflammatory state.
Dr. Resnick responded to a few questions. One was how do you know that the effects were solely due to the primary cilium. The results all used calcium detection to measure the results. A series of tests were done indicating that the cilium was the only part of the cell that interacted with calcium.
We thanked Dr. Resnick for his excellent presentation.
Bob Erdman, Secretary
Meeting Announcement: June 4, 2012 - TANGIER, 6:00 PM
Dr. Richard Elliott, Department of Chemical Engineering, University of Akron
will be speaking on:
Applied Thermodynamics for Nanoengineering in the 21st century
Minutes, June 4, 2012
JUNE 4 BUSINESS MEETING MINUTES:
Treasurer Dan Galehouse reports there were two guests @ $18 each (-), 19 paid meals which contribute at $1 each (+) and donations of $21 (+). The balance is $389.45 - $36 + $19 +$21 = $393.45. This total agrees with the amount of money in the polypropylene box.
Erdman reported on ACESS activities: advisory meeting was held consisting of over 20 people, to discuss ACESS and activities of each member society. Galehouse presented a fine overview of our club, communicating the program and the informality with which we operate. Many societies have a mailing list much larger than ours, and have less attendance than we do. This seems to be a trend in all local technical societies.
A Questionnaire was developed, emailed, and a few copies were placed on the tables. These provide essential inputs for the officer meeting over the summer. Chair Ernst pointed out that questions such as location, schedule, and programming ideas are very important and this is a vehicle for collecting thoughts on these matters from everyone. Such positions as "we should only have pure physics talks" and "If it is the kind of thing that would appear in Scientific American, it should be included" are not reconcilable at the policy level, so we really need everyone's inputs to address such questions.
Charles Lavan, Program Chair, reported receiving some negative feedback on our last meeting. Although Dr. Resnick gave a good talk, it seems that some do not care about the interface between biology and physics. [Your Secretary pointed out that one survey response indicated that this was an excellent talk, and we need more talks involving biology and physics. So we ARE a diverse group.] Next fall we have Will Jack in September talking about his home-made fusion reactor, and in October we have Dr. Colin Drummond from Case Western Reserve University who will discuss his work on nanosensors. Dr. Chris Martin of Oberlin is now scheduled for Nov. 26.
Charles is exploring many possibilities for other speakers next club year, which will be pursued once we have our summer meeting and settle such issues as scheduling and location. One of these possibilities is Mary Elizabeth Wade, a Graduate Student in Integrated BioSciences at the University of Akron, who is studying coloration and other characteristics of bird feathers. Another is Dr. Michael Mann of Penn State, a theoretical physicist and climatologist. He has written a book: "The Hockey Stick and Climate Change Denial".
Chairman Ernst von Meerwall introduced our speaker, Dr. Richard Elliott, who got his BS from Newport College, 1980, his MS from VPI in 1982, and PhD from Penn State University in 1985. He is a Chemical Engineering Professor at The University of Akron focusing on thermodynamics. He wanted to talk about molecular perspectives: How we present molecular physics to Chemical Engineers, teaching statistical mechanics to undergraduates without using the phrase "partition function", and some newer teaching techniques for molecular physics.
NOTES ON DR. ELLIOTT'S PRESENTATION
[Including material from the abstract]
The length scales of interest in engineered materials have shrunk to the point where conversance with molecular interactions is a necessary prerequisite for engineering graduates (especially chemical engineers). Examples of molecular interactions include the intermolecular potential energy and hydrogen bonding that lead to solubility parameters and hydrophobicity. Using freely available molecular modeling tools like those at www.etomica.org, we can provide visual tools for making the connections between molecular interactions and macroscopic observations. Simultaneously, these simulations illustrate connections between translational energy and temperature, unimolecular interactions, and drastic defects in the ideal gas model.
The topics presented are based on a square-well model of potential energy. The goal is to use the minimum number of square-well potentials to efficiently and effectively simulate a smooth potential function. The symbol for interaction between molecules, the potential wells, is u. U is the total energy, including rotational and translational energies. For two point charges, we think of potential energy as varying with distance in a 1/r2 relationship. But molecules can have multiple regions of positive and negative charge, and are tumbling in 3 dimensions, resulting in a 1/r6 or 1/r7 relationship, such as in the Lennard-Jones potentials, which are being simulated effectively with a minimum number of square-wave potentials.
So in the real world, the only energy that can be measured is U, the total energy, and that is always an observed average. For example an Atomic Force Microscope measures an area of about 200 atomic diameters. An issue is how to distinguish the various interactions contributing to U, based on the details of individual interactions between atoms, u. This can be examined looking at two molecules near each other, each with interactions among their constituent atoms and interactions with atoms of the other molecule.
An azeotrope is a substance having the same composition whether in liquid or vapor state. In mixtures, the constituents cannot be separated by distillation. For example in making ethanol, it takes about 30% of the fuel value to go from 95.6% ethanol, 4.4% water to 99.9% ethanol. Ethanol contains CH2 and CH3, which do not mix well with water. As the water is surrounded by CH2 and CH3, the hydrogen bonds in water are broken, forming methane. The boiling point of methane is 111K, vs. 100 degrees C for water. Thus it is more volatile than the ethanol. As the methanol percentage increases, there comes a point at which the volatility of the mixture is the same as that of ethanol, [thus it is an azeotrope] and it cannot be separated from it by distillation.
The van der Waals equation of state does fit the vapor pressure well, since it only matches a point, not the slope, so Peng-Robinson equations of state are used. These are based on the detailed molecular interactions discussed earlier. An extension of that perspective to mixtures establishes a linkage to the van der Waals perspective on mixture models (regular solutions, Margules, Scatchard-Hildebrand, Flory-Huggins models). From there, a relatively simple perspective leads to a separation of cohesive energy density (SCED, ie. d2 where d =solubility parameter) into a hydrogen bonding part and a dispersive energy part.
To make these insights more rigorous requires extending molecular simulations from spherical molecules (like www.etomica.org) to chains with rings and branches. Furthermore, the molecular interactions must be characterized with atomistic detail including the influences of polarity and hydrogen bonding, and the results need to be summarized in a form that permits instant computation over broad ranges of temperature, pressure, density, composition, and molecular weight. Hard-sphere models and square-well models more accurately describe vapor phase than the ideal gas model, which postulates no interactions. The advantage of the more detailed insights is specific guidance about tailoring specific molecular structures for specific applications. For example, new plasticizers for poly lactic acid (a relatively new, “sustainable” polymer made from corn starch) require different structures from the more familiar ones for polyvinyl chloride. The diffusivity of the plasticizers must also be managed, but transport properties are a natural byproduct of this more holistic molecular modeling perspective. Tools for molecular modeling at this level are also freely available (e.g. www.speadmd.org).
We thanked Dr. Elliott for his excellent presentation. Please contact your Secretary if you want a set of slides from the talk or if you need a copy of the questionnaire.
Meeting Announcement: MONDAY, September 24, 2012 - TANGIER, 6:00 PM
Will Jack, Hudson High School
will be speaking on:
Neutrons in the basement: Building IEC Fusion Reactors at Home
Electrostatic Confinement (IEC) fusion reactor is a technology first developed by Philo Farnsworth in the mid-1960’s capable of carrying out fusion reactions between various light nuclei. This talk focuses on the problems, solutions, successes, apparatus, and methodologies involved in a teenage amateur scientist’s attempts at constructing, operating, and analyzing IEC reactors; all while operating on a shoestring budget in a basement laboratory.
Will Jack is a 17 year old senior at Hudson High School. Since beginning work in the field of inertial electrostatic confinement (IEC) fusion he has built two IEC reactors capable of carrying out deuterium-based fusion reactions. He has attended the Intel International Science and Engineering Fair twice with these reactors and has won a number of awards at the fair including the Coalition for Plasma Science’s Grand Prize, a First Prize from the Navy in Bioengineering, and a second place Grand Award in the category of Materials and Bioengineering. Will is currently developing new methods of inexpensive medical imaging based on IEC technology.
Please join us for this unusual and interesting talk, to see what scientists of the future can and are doing today. This is a fascinating tour of an excellent project done by a thorough scientist and the learning that resulted from the experience.
Minutes, September 24, 2012
Report on the September 24 meeting:
In addition to the 30 people who attended the dinner at this meeting, we had about 15 visitors who were classmates of Will Jack's making this record attendance in recent years.
Visitors: Will Jack, our Speaker, introduced fellow students from the New Dimensions class at Hudson High School, many of his teachers, and his parents. Also introduced were Alain Azad and his son, Volodomyr Borshch from Kent State Liquid Crystal and others, Including John Sommer's son and granddaughter.
Charles Lavan reviewed the programs for the rest of the year, all of which are now arranged.
Oct. 22: Dr. Robin Selinger, Kent State Liquid Crystal Institute on Liquid Crystal Elastomers.
Nov. 26: Dr. Chris Martin, Oberlin College on the Herschel Intergalactic Gas Survey.
Jan. 28 2013: Dr. Mathew Shawkey, University of Akron on The Physics, Optical Effects and Color of Bird Feathers
Feb. 25: Dr. Martin Tsige of University of Akron on Molecular Dynamics Simulations
Mar. 25: D.r Peter Hoekje of Baldwin Wallace University on Music, Flutes and Physics.
April 22: Dr. Peifang Tian of John Carroll University on Imaging 3-D Spatiotemporal Hemodynamics in Vivi using 2-photon Laser Scanning.
June 3: Dr. Jay Reynolds of Cleveland State University and Lakeland Community College on DAWN: Mission to Asteroid VESTA
[You may wish to save this list: Only the next topic will appear in future minutes.]
We Gave Dr. Lavan a hand for his fine work on setting up the program.
Treasurer's Report [Finalized after the meeting]:
The income was: $28 x 19 paid dinners +$3 donations = $535.
Expenses were: $18 x 32 meals = $576.
The loss is $41 bringing our treasury down to $352.45 from $393.45.
Bob Erdman Reported that there is a discussion between mentors and students in science participating in Science fairs in Kent on October 6. Bob mentioned that he advised Will and had many great discussions with him.
Chairman Ernst introduced Will Jack, the speaker, noting that he is the first High School student who has spoken to the Physics Club, and how honored we are to have him speak. Ernst also commented that the talk is really a wonderful saga about the trials of an experimentalist, and the learning that comes from fixing each problem as it arises.
NOTES ON WILL JACK'S TALK ON NEUTRONS IN THE BASEMENT:
Will is now a Senior at Hudson high School, and has enjoyed building scientific devices and experimenting with science in his basement for the last few years.
Nuclear fusion is smashing two light nuclei together causing them to fuse. Will dissociated his work from the cold fusion work by Fleishman and Pons and the more recent e-cat Rossi experiments which claim energy gains. In Will's Inertial Electrostatic Confinement [IEC] Fusion Reactor, a high voltage ionizes deuterium atoms, leaving just a positively charged nucleus consisting of a proton and a neutron. The negative high voltage in the center of the reactor accelerates the ions toward the center with enough energy that occasionally two of them collide. In some of the collisions, a helium-3 atom is formed along with a neutron ejected at 2.45 MeV. In others, tritium [hydrogen-3] and a proton result from the collision. This concept was first implemented by Philo Farnsworth in the 1960s. Farnsworth was earlier involved with the develop of TV and the cathode-ray tube. Three years ago Will got interested in this work and decided to build his own fusion apparatus.
The first apparatus Will built was a demonstration apparatus in a Pyrex bell jar using a neon sign transformer to supply high voltage. It did not produce fusion, but did create a plasma of ionized gas, which emits light due to recombination of the electrons after ionization. Will learned a lot about high voltage, vacuum and other technologies involved by building this first apparatus.
He then wanted to build a complete apparatus to create fusion, which required a metal chamber, lower pressures [better vacuum], higher voltages, a deuterium gas injection system and a system for detecting neutrons. This was in a stainless steel sphere, consisting of two machined hemispheres, in order to block x-rays generated by the high voltage. These included a view port and a vacuum flange. Will washed the hemispheres in water, and learned that water is easily absorbed by stainless steel, thus it kept outgassing and he could not get a good vacuum. When he cleaned it with acetone, it supported a better vacuum. He added a diffusion pump, which permitted the system to get down to a pressure of 0.1 mtorr.
In order to get a high voltage, he tried a voltage doubler circuit with a neon sign transformer and microwave capacitors, which had many exposed hazardous voltages and involved a salt-water resistor which generated hydrogen. Realizing that this was quite dangerous, he obtained a used commercial 30kV supply instead, and built a home-made controller for the supply.
He obtained a 25-liter [volume at STP] lecture bottle of deuterium. He needed to reduce the pressure from 700psi in the tank to a very low pressure for injection into the vacuum space. He got a throttle valve, and connected a system using copper tubing. this design had vacuum leaks. He replaced the copper with stainless steel tubing, and got the system to operate at the 1mtorr vacuum level needed, cleaning components with acetone and using a lot of vacuum grease..
In order to verify that fusion occurred he needed to monitor neutrons coming from the reactor. These easily pass through the walls of the rector sphere. Protons stay inside the chamber, and the amount of tritium produced is too small to be detected, leaving neutron detection as the best method to verify fusion. He first tried radioactive silver, but this did not work. He then obtained a boron-10 proportional tube, which ejects a alpha particle when bombarded with neutrons. The alpha particles in turn ionizes air creating a current pulse as in a Geiger counter. He ran tests to compare the background and electromagnetic interference of around six tenths of a count to 200-300 counts per minute when the moderator is placed over the Boron-10 tube. Water was used for the moderator, which reduces the velocity of the neutrons so the Boron-10 tube can detect them. This made a clear observation that neutrons were generated, verifying that fusion occurred.
The third version, only 11 inches wide by 17 inches tall, has fully remote controls on the voltage and the throttle valve position, and monitors voltage and current. It can continuously operate, rather than be limited to about 2 minutes as the last version was. A four-way cross was used rather than a sphere. The reactor has an ion source on it that uses a magnetic field to trap electrons and forces them to take long helical paths through neutral deuterium gas, increasing the probability of an ionization event occurring between a neutral gas atom and an electron (an event which results from a collision between the two). The magnetic field has no significant effect on how the fusion reactions occur. Because of sustained operation, many materials used for the heater melted. He finally used tungsten which has not yet melted. There is some heating due to ions hitting the stainless steel walls of the chamber.
One use of the reactor would be to make radioactive materials by bombarding them with neutrons made by the reactor, for example silver107 becomes silver108 because the neutrons rather easily fuse into the silver107 nucleus. Silver has a large neutron capture cross-section, increasing the probability of a neutron capture event. Will coated a photomultiplier tube with a "scintillation cocktail" which emits a pulse of light for each incidence of a radioactive particle. This can be used to detect radioactivity on silver108 and silver110. He ran tests on this and saw the expected decay of radioactivity from the silver isotopes.
From here, Will hopes to build a water-cooled apparatus that could be run continuously without heating. He will add programmed controls to avoid having to adjust controls during experiments. He is looking at possible uses in medical imaging.
After a round of applause, Will answered a few questions on vacuum, open-source software, things that he learned from the project [mainly a lot of experimental technique], and some of his new ideas for where to go from here.
Bob Erdman, Secretary
Meeting Announcement: MONDAY, October 22, 2012 - TANGIER, 6:00 PM
Dr. Robin Selinger, Liquid Crystal Institute, Kent State University
will be speaking on:
Rubber that Moves: Liquid Crystal Elastomers
Liquid crystal elastomers, sometimes called "artificial muscles," combine the elastic properties of rubber with the molecular order properties of liquid crystals. These fascinating materials stretch, shrink, bend or flap in response to changes in temperature, illumination, or applied electromagnetic fields, due to strong coupling between orientational order and elastic strain. Their mechanical behavior is also unusual, showing in some geometries a pronounced plateau in stress-strain response. "Blueprinting" a spatially varying pattern in the director field of a thin LC elastomer film produces reversible deformations into complex shapes under heating and cooling. Our modeling efforts capture the fundamental physical mechanisms driving these shape transformations and provide predictive tools for engineering future device applications.
Robin Selinger serves as Professor at the Liquid Crystal Institute & Chemical Physics Program at Kent State University. Her research interests lie in computational soft matter science using statistical physics, molecular scale, mesoscale, and continuum simulation techniques. She earned both AB and PhD degrees in physics from Harvard University, and did postdoctoral work at UCLA, the Univ. of Maryland and NIST. She served as a faculty member at the Catholic University of America for ten years before moving to Kent State in 2005. She is active in science outreach programs and is immediate past-president of the Hudson STEM Alliance, a local nonprofit that promotes extracurricular programs for K-12 students in Hudson and surrounding communities.
Minutes, October 22, 2012
Report on the October 22 meeting:
Chair Von Meerwall, Assistant Chair Reneker and Program Chair Lavan were all out of town, so Secretary Erdman and Treasurer Galehouse ran the meeting.
No comments were made on the Sept. 24 meeting, but after the meeting a typo was pointed out in the schedule for the year: The February 25 speaker will be Dr. Mesfin Tsige. As secretary, Erdman apologizes for this typo.
Visitors: Jacqueline Carpenter and Jennifer Syms are Physics Students at the University of Akron. Glenn Atwood, retired after 25 years as a Chemical Engineering Professor at the University of Akron.
Treasurer's Report [Finalized after the meeting]:
The income was: $19 x 16 paid dinners +$3 donations = $307.
Expenses were: $18 x 19 meals = $342.
The loss is $35 bringing our treasury down from $352.45 to $317.45.
This calculation agrees with an actual count of our treasury.
It was suggested by a few people that we raise the charged cost to $20 to cover student dinners.
Erdman Reported that there were 5 advisors from the Physics Club who came to a "Brainstorming Session" for middle- and high-school science projects at Kent Stanton School on October 6. We had the right amount of Physics Advisors thanks to those who came, and they enjoyed the discussions with the students.
Erdman introduced Dr. Robin Selinger of the Kent State University Liquid Crystal Institute, our speaker for this evening, citing the material in the announcement of this meeting.
NOTES ON Dr. ROBIN SELINGER'S TALK ON RUBBER THAT MOVES: LIQUID CRYSTAL ELASTOMERS
Dr. Selinger opened the talk by introducing the group of Researchers who did this work, some of whom have moved on to Post-Doc positions in other institutions all over the country. She showed liquid crystal elastomers that move under various excitations: Heat, causing the elastomer to decrease its length as it gets warmer; Photons from a laser bombarding one side of a rod, causing it to bend; and an Electric Field applied to an elastomer with electrodes on each side, causing it go back and forth as positive and negative electric fields are applied.
She reviewed various liquid crystal phases: Isotropic [disordered], Nematic [lengthwise aligned], Smectic [aligned within a layer], and Twisted Nematic, where in the alignment is rotated by electric field, as in a liquid crystal display. In polymer liquid crystals, in general the order is destroyed by an outside excitation: Heat destroys the nematic order, reducing the length of a rod; Light causes AZO dye molecules to fold vs. remain straight, reducing the length of one side of a rod, cause it to bend; Electric field causes a smectic layer to elongate and get thinner due to tilting of the molecules, causing one side to expand and the other contract, thus the flat material moves first one way then the other as the field is reversed.
In order to model these elastomers, Dr. Selinger used a tensor form of Hooke's Law combined with finite element analysis techniques. Tetrahedra were not suitable for the modeling, since they do not occupy all space, so she used mesh software for this analysis. Using small mesh elements, the model utilizes a point mass in each element. Using 1 microsecond time elements, graphs were shown of potential and kinetic energy that added to form a constant sum. Friction can be added to this model. In order to describe nematic order, a tensor was used which quantifies alignment with a director field. A large strain-order parameter [S] in this tensor indicates good alignment, a low value indicates more disorder; S=1 is purely nematic crystals, S=0 is purely isotropic crystals. Using these modeling techniques, the above responses to excitations can be quantitatively analyzed and compared to experimental results.
If the Strain-order parameter S varies from front to back of the material, a twist occurs in the material. The aspect ratio of the material and the temperature determine whether it is a right-handed or left-handed twist, and whether it forms a helicoid or a spiral ribbon. In order to analyze a complete liquid crystal elastomer system then, the finite-element analysis must include not only the Hooke's law term, but a term for strain-order parameter, an energy term for cross--linked memory changes and a term for the energy cost of an orientation gradient. Using this more complete analysis, the modeling successfully predicts the observed behaviors of the materials involved.
The overall goal of this work is to "Build a bridge between basic soft-matter theory and practical materials engineering/device design." Toward this end, a number of illustrations have been implemented or conceived: A traveling earthworm activated by light, a torsional oscillator, a channel pump which has peristaltic action to pump fluid through the middle of a tube, devices which bend in response to incident polarized light, polymer films which move in response to light, photo-activated micro valves, Braille displays for the blind, self-actuating unfolding origami, actuators, robots and other real moving devices.
Questions were asked about the possibilities for invisible cloaking devices, which they are talking about along with other action devices which are photo activated. Also the question of wavelengths to which the devices are sensitive came up, which is determined by the azo dye. Force and strength of devices using this technology are similar to human muscles, for which liquid crystals with flexoelectric response can be made, which bend in response to applied voltage or generate voltages proportional to the bend. This work was done by Tony Jakli at Alpha Micron in Kent, [who might be an interesting speaker for us].
Bob Erdman, Secretary
Meeting Announcement: MONDAY, November 26, 2012 - TANGIER, 6:00 PM
Dr. Chris Martin, Oberlin College
will be speaking on:
Feeding the Black Hole in the Center of the Milky Way:
Observations from Antarctica, long duration balloons, and the Herschel Space Observatory
Feeling a bit hungry? Imagine that you only received one meal every few million years, and that when you ate it, it was a gigantic Thanksgiving feast. That sort of gorging might give you quite a stomach ache! The black hole at the center of our galaxy seems to go through just this cycle of feast and famine, but as the turkey dinner arrives it bursts into a tremendous display of fireworks. Instead of turkey, a black hole eats a vast platter of dust and gas that is compressed and stressed as it reaches the inner part of the galaxy. This compression causes the formation of a plethora of large short-lived stars that go supernova shortly after their birth. These supernova fireworks would then be sufficiently intense to make the center of the galaxy one of the brightest objects in our night sky while at the same time sterilizing any life that might be nearby. How does this matter get to the center of the Galaxy and when can we expect the next burst of fireworks? At this very moment the dinner plate for the black hole at the center of the Milky Way is being assembled and a group of astronomers is looking at the menu using telescopes on the ground, on balloons, and in space. Dinner will be served in about 10 million years.
Dr. Chris Martin is a professor of physics and astronomy at Oberlin College in Oberlin, OH, and spent a year as an American Association for the Advancement of Science Congressional Fellow with the United States Senate Committee on Commerce, Science,and Transportation. As a scientist, Dr. Martin studies the Milky Way Galaxy using the Herschel Space Observatory, long duration balloon missions, and telescopes around the world. Prior to joining the faculty at Oberlin, Dr. Martin was the Station Science Leader at the Amundsen-Scott South Pole Station and spent two years wintering-over at the bottom of the Earth.
Minutes, November 26, 2012
Report on the November September 26 meeting:
Chair Von Meerwall remembered Alan Gent, a long-time member of our club.
Dr. Dan Galehouse, Treasurer had not finished counting everything at the meeting, but sent the following report after the meeting:
There were 29 meals paid in at $19 and 30 meals paid out at $18 for a net gain of $551-$540 = $11.
There were additional donations totaling $5. This would give a new balance of $315.45 + $16 = $331.45 except that also Tangiers gave us one free $18 meal. This augments the balance to $331.45 + $18 = $349.45. The money in the polypropylene box agrees with this.
Dr. Charles Lavan reviewed our upcoming meetings. After Dr. Shawkey of Akron University speaks in January, other talks will be as listed in previous minutes and on the website.
Since our treasury has declined by $100 over the last year, Erdman moved that dinner price be raised to $20. The motion was seconded and passed unanimously.
Erdman also announced that the Wilson family and the Spectroscopy Society of Pittsburgh are jointly sponsoring a Charles W. Wilson Scholarship in Physics at the University of Akron. Here is Jan. 10 info from Will Wilson. It is now all set up:
Contact Carin Lulli, The University of Akron Foundation, Department of Development
Martin University Center, The University of Akron, Akron, OH 44325-2603.
The family appreciates the interest of Physics Club members in keeping Charlie's memory alive.
Visitors: Reid Parsons, age 18, who has entered some physics experiments in science fairs which received Superior ratings up through the state competitions, and who expects to be attending Ohio State University in the fall of 2013, majoring in physics, joined us. Gary Davis of the Astronomy Club joined us and brought his son William, age 11, who has an interest in astronomy and participated in the discussion,
Chair von Meerwall introduced Dr. Chris Martin on the Physics and Astronomy faculty at Oberlin College. He spent a year as an American Association for the Advancement of Science Congressional Fellow with the United States Senate Committee on Commerce, Science, and Transportation. As a scientist, Dr. Martin studies the Milky Way Galaxy using the Herschel Space Observatory, long duration balloon missions, and telescopes around the world. Prior to joining the faculty at Oberlin, Dr. Martin was the Station Science Leader at the Amundsen-Scott South Pole Station and spent two years wintering-over at the bottom of the Earth.
NOTES ON THE PRESENTATION:
The focus of the talk is on the Milky Way, which consists of many stars, a lot of space, gas and dust, some black holes, nebulae, dark matter and a lot of dark energy. There are about 1 trillion stars are in the Milky Way. Distance between stars is typically 1 to 10s of light years. To get some idea of the density of stars in the Milky Way: If each star was represented by the volume of a grain of sand, the bed of a pickup truck would hold roughly 1 trillion grains of sand, and on the same scale, the volume of the Milky Way would be about the volume of the entire earth. So the density of stars in the Milky Way is so low that chances of a random collision between them are virtually zero.
Most of the universe consists of 3/4 hydrogen, 1/4 helium. Other elements were generated by stars involving larger atoms. When viewing stars using visible light, clouds and dust interfere with the light rays making it difficult to see. Radio waves, which have longer wavelengths penetrate clouds and are not as affected by dust,. Thus radio astronomy is more useful astronomy in many situations. Visible light emitted from a star has an equivalent temperature a few thousand degrees K, and only represents a small fraction of the electromagnetic spectrum of the universe. Radio astronomy can explore a much wider spectrum of frequencies than visible light, and thus see many more types of bodies, including dust clumps where stars are formed and gas, yielding much more information.
Dr. Martin observes carbon monoxide [CO] because this molecule has a dipole moment, so it interacts with electromagnetic waves by oscillating at defined frequencies and emitting photons. Hydrogen atoms have minimal dipole moment and thus do not interact well with waves. The oscillation frequencies are quantum mechanically defined. He listens to these using a sensitive superhetrodyne receiver, which converts the difference between the received and a generated signal frequency to an audible sound. The South Pole is a great place to do these experiments, since there is minimal background electromagnetic noise. He plots velocity of the object, as determined by Doppler shifts, against its position and the intensity of emission.
Gravitational orbits around a single mass are all conic sections; a circle, ellipse, hyperbola, etc. Our galaxy and many others consist of a bar, rather like a cylinder, with spiral arms at each end. Bars are driven by density waves [analogous to traffic velocity on a busy highway: Go slowly in busy traffic, then suddenly it is possible to go near the speed limit again]. The spiral arms obey gravitational orbits, but the bar is a more rectangular orbit rather than a conic section. Spiral arms must start at the ends of a bar, not internal to it. Stars traverse through the galaxy by traveling with a spiral arm for awhile, then moving to another arm. Dust and gas orbit around the bar in different patterns than the conic sections of gravitational systems around a single body. These are known as X1 and X2 orbits; these create new stars, and end up disintegrating into a black hole at the center. Every few hundred million years, the black hole at the middle goes into "starburst" mode, making many stars, all very intense. This activity and supernovas occur near the center of the galaxy.
Herschel is a European satellite, in an orbit about 4.5 times the distance of the moon. It launched using an Ariane 5 launcher. One problem in this satellite is that the microcontroller was not built using radiation-hardened semiconductors, so occasionally the controller exhibited erratic behavior. This took years to correct. In the meantime, his group used helium balloons in a circular wind path orbit around the South Pole, so they could be brought down and reused when they again came over the launch site, 14 to 100 days later.
Bob Erdman, Secretary