Skip to content

Spring 2011 Colloquia

Physics and Astronomy Colloquium - Spring - 2011 (4-5pm, Science Bldg. 127)


January 20 - Constraining Properties of Neutron Stars with Terrestrial Nuclear Reactions


Dr. Bao-An Li
Department of Physics and Astronomy, Texas A&M University-Commerce

LiDr. Bao-An Li conducts research in nuclear physics and astrophysics. The goal of his recent work is to understand properties of dense neutron-rich nuclear matter that can be produced in terrestrial nuclear reactions and may also exists in the core of neutron stars. The results of his work may help better understand the origin of elements and nature of matter under extreme conditions as well as the evolution of the Universe. His recent publications can be found here
<http://xxx.lanl.gov/find/nucl-th/1/au:+Li_Bao_An/0/1/0/all/0/1>.
You can also get a feeling about the impact of his research by checking out the citations of his publications at Google Scholars
<http://scholar.google.com/scholar?q=Bao-an+Li&hl=en&lr=>  
or at SPIRES.
<http://inspirehep.net/author/profile/B.A.Li.4>
Dr. Li’s research is currently funded by the National Science Foundation, NASA and the Texas Coordinating Board of Higher Education.

Abstract
Neutron stars are highly condensed stellar objects produced in supernova explosions, the end point in the evolution of more massive stars. The masses of neutron stars are in the range of 1-2 times of the sun, whereas their typical radii are only 10-20km. The matter they contain, primarily neutrons, is therefore the densest found outside black holes in the universe. Neutron stars thus provide a laboratory to test our understanding of nature at the extreme, and verify our theories of matter, energy and their interactions. However, neutron stars are still among the most mysterious objects in the universe and they pose a great scientific challenge. The structure and properties of neutron stars are determined by the Equation of State (which is a relationship among the pressure, density and temperature) of neutron-rich nuclear matter. For the EOS of neutron-rich nuclear matter, what has been most uncertain is the symmetry energy term related to the energy cost of converting protons into neutrons in nuclear medium at various densities.  Nuclear reactions conducted in terrestrial laboratories, especially heavy-ion reactions induced by highly neutron-rich radioactive beams, can produce nuclear matter similar to those contained in neutron stars. In this talk, I will first review the latest theoretical and experimental progress in constraining the EOS of neutron-rich nuclear matter, especially the density dependence of the nuclear symmetry energy, using nuclear reactions in terrestrial laboratories. I will then discuss several key astrophysical ramifications of the EOS partially constrained by the latest experimental data from several nuclear physics laboratories around the world.

January 27 - How Strange is the Proton? A collection of interesting puzzles for the LHC (Large Hadron Collider)

Prof. Fredrick I. Olness
Department of Physics, Southern Methodist University

 

olnessProfessor Fredrick Olness received his B.S. from Duke University (1980), and his M.S. and Ph.D. from the University of Wisconsin (1982,1985). Continuing his work-across-America tour, he took postdocs at Illinois Institute of Technology in Chicago (1985-88) and the University of Oregon in Eugene (1988-91), before joining SMU in 1991 where he is now an Professor of Physics. He served as Department Chair from 2001-2007, and again from 2010 to present.  In 2010 he was selected as the Dedman College distinguished Professor. Professor Olness currently serves as Co-Spokesperson of the CTEQ Collaboration (cteq.org).  He spent the 1997-98 academic year on sabbatical with the Theoretical Physics Group at Fermi National Accelerator Laboratory, and the 2007-08 academic year on sabbatical working on the LHC (Large Hadron Collider) at the CERN (Conseil Européen pour la Recherche Nucléaire) laboratory in Geneva Switzerland. In 2005 Olness was elected as an APS Fellow for "For significant contributions to understanding nucleon structure and heavy quark production in perturbative quantum chromodynamics."  Each year, no more than one-half of one percent of the then current membership of the Society are recognized by their peers for election to the status of Fellow in The American Physical Society. Prof. Olness served as President of the SMU Faculty Senate for 2009-2010. He received a SMU Ford Fellowship in 2008, the SMU "M" Award in 2007, the SMU Distinguished University Citizen Award in 2006, and the President's Associates Outstanding Faculty Award in 2000. He is also the Director of the Dallas Regional Science & Engineering Fair. His research is in elementary particle physics phenomenology, at the interface between theory and experiment.  Specifically, he studies Quantum Chromodynamics (the fundamental force that binds nuclei) to help answer the questions: What are the fundamental building blocks of nature, and what holds them together? Fredrick initiated the DOE theory grant at SMU in 1992, was awarded an SSC Fellowship in 1993, and is an active member of the CTEQ collaboration--a novel collaboration of theorists and experimentalists. He has written over 100 research articles, served as a convener for international workshops and conferences, and has been an invited speaker for international conferences and summer schools. On the side, he presents "The Physics of Music" and "The Physics Circus" public lectures to local schools, and is the co-director of the Dallas Science Fair. Outside of physics, he entertains himself (and others) playing his trumpets for church services and weddings. More information about Prof. Olness and his research can be found at
http://www.physics.smu.edu/~olness/www/index.html

NOTE: the picture above of Prof. Olness during a conference in 2001, shows an interesting (but dangerous) use of units.

Abstract:
Although we've been measuring the structure of the proton for decades, the strange-quark content of the proton (as well as the heavier c and b flavors) is relatively unconstrained. The broad kinematic reach of the Large Hadron Collider (LHC) increases the role of the s,c, & b components; this has important implications for the LHC "benchmark" processes such as W and Z boson production which are a crucial stepping stone to the Higgs discovery.  We review the recent data as well as theoretical advances which are enable an enhanced analysis of the LHC data.

February 3 - Patterning silicon surfaces by chemical self-assembly for biomedical and energy applications (Cancelled: TOO MUCH SNOW IN TEXAS!)

Prof. Yves J. Chabal
Department of Materials Science and Engineering, University of Texas at Dallas

chabal Yves Chabal holds a Texas Instrument Distinguished University Chair in Nanoelectronics at the University of Texas at Dallas. He obtained a BA in Physics from Princeton University in 1974, and a Ph.D. in Physics from Cornell University in 1980. He then joined Bell Laboratories where he developed sensitive spectroscopic methods to characterize surfaces and interfaces. He worked at Murray Hill, New Jersey, from 1980 until 2002 for AT&T, Lucent Technologies (1996) and Agere Systems (2001) in the Surface Physics, Optical Physics and Materials Science departments. In 2003, he joined Rutgers University as Professor in Chemistry and Biomedical Engineering, where he expanded his research into new methods of film growth (atomic layer deposition), bio-sensors, and energy (hydrogen storage).  He directed the Laboratory for Surface Modification, an interdisciplinary Center to promote large initiatives. 

Yves joined UT Dallas in January 2008 to lead the Materials Science and Engineering department in the Erik Jonsson Engineering School. This department is located in the new Natural Science and Engineering Research Laboratory building, where interdisciplinary research is carried out among several departments (Biology, Chemistry, Physics, Electrical Engineering, Brain Science, and Medical Research). Yves is a Fellow of the American Physical Society and the American Vacuum Society, received a Bell Laboratories Affirmative Action Award (1994), an IBM faculty award (2003), the Rutgers Board of Trustees Award for Excellence in Research (2006), and the Davisson-Germer Prize (2009), and the Tech Titan Technology Innovator Award in 2010. He is the author of more than 330 publications (>12,500 citations), 10 book chapters, several patents and the editor of a book on the Fundamental Aspects of Silicon Oxidation. More information about Prof. Chabal and his research can be found at http://mse.utdallas.edu/people/chabal.html

Abstract:
Future devices for biomedical and energy applications are likely to use hybrid organic/inorganic junctions. Semiconductor substrates are often used because they are particularly appropriate for electronic sensing and photo-electric or voltaic devices. For instance, field-effect transistors (FETs) are being developed as biosensors, wherein the electric field induced by the attachment of a charged biomolecule onto an organic self-assembled monolayer (SAM) results in a change of the FET drive current. Similarly, attachment of light-absorbing molecular groups or nanoparticles on a SAM-covered semiconductor surface is being considered for high efficiency photovoltaic devices. In all cases, the performance of such hybrid devices critically depends on the quality and stability of the organic/semiconductor interface. 
In this talk, we suggest that the formation of SAM on oxide-free silicon surfaces can lead to higher chemical stability and electrical performance than on oxidized silicon surfaces that are currently used. It is known that hydrogen-terminated surfaces are ideal starting point for such oxide-free organic functionalization, but the functionality (i.e. versatility) of current SAMs is limited when simple hydrosylisation methods are used. Chemical functionalization of H-terminated silicon is therefore critical to further developments. We present new results that greatly facilitate the grafting of a variety of molecules directly on Si, using both wet-chemical and gas-phase methods. For instance, we show that it is possible to form fluorine or hydroxyl terminated Si surfaces by simple HF etching or water immersion without formation of silicon oxide, and that F-terminated Si surfaces can be used for easy “snap-on” chemistry. An essential ingredient for this process is alcohol, although not for the experimenter!

February 10 - Stellar Necroscopy: Using white dwarfs to probe the end stages of stellar evolution (Cancelled: TOO MUCH SNOW IN TEXAS, again!)

Prof. Kurtis Williams
Department of Physics and Astronomy
Texas A & M University-Commerce

Kurtis Williams
Dr. Kurtis Williams is a new faculty member at Texas A&M University – Commerce. He studied astronomy and physics as an undergraduate at Penn State University, after which he spent a year as a Fulbright Scholar at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. He earned his doctorate in Astronomy & Astrophysics from the University of California Santa Cruz in 2002.  He then was a postdoctoral research at Steward Observatory in the University of Arizona and a National Science Foundation Astronomy & Astrophysics Postdoctoral Fellow at the University of Texas in Austin. His research interests are widely varied, and have included X-ray astronomy, white dwarfs and stellar evolution, gravitational lensing, and galaxy evolution.

Abstract:
White dwarfs are the final state of stellar evolution for the vast majority of stars ever formed, and are ever-cooling remnants of their progenitor star's central nuclear reactor.  As such, white dwarfs are an ideal observational probe of the end stages of the stellar life cycle.  In this talk, I will first present our latest results in understanding the relationship between white dwarf masses and the masses of their progenitor stars.  Second, I will discuss the numerous mysteries surrounding a rare type of white dwarf, those with carbon-dominated atmospheres.  Finally, I will outline a new project to determine the age of the thick disk and halo of the Milky Way galaxy using data from a recently-completed survey of the northern sky.

February 17 - Thermal Properties of Nanowires

Prof. Mark Holtz
Department of Physics
Texas Tech University

HoltzProf. Mark Holtz received his B.S. in Physics from Bradley University and his Ph.D. in Physics from Virginia Tech. He spent time as a visiting researcher at Max Planck Institute and Michigan State University prior to joining Texas Tech University. Since that time, he has carried out research in solid-state physics and earned promotions from Assistant up to Professor of Physics. During this time he spent summers and semesters at Intel, Corp., Texas Instruments, Inc., and the Army Research Laboratory. He has been the Arts and Sciences director of the TTU Nano Tech Center since 2004. More information about Prof. Holtz and his research can be found at
http://www.phys.ttu.edu/faculty/new_mark.html
 
Abstract: 
Thermal Conductivity at the Nanoscale Self-heating in device materials results in degradation of performance and sometimes failure. This problem is more drastic at the nanoscale due to generally increasing electrical resistivity and decreasing thermal conductivity. Despite the importance of this problem, there are very few studies of the impact size effects have on these fundamental quantities. At Texas Tech we have examined the effect of size in metallic structures with nanoscale dimension, for which both electrical and thermal conductivities are significantly different from their bulk counterparts. The total thermal conductivity is generally the sum of the electronic and phonon contributions. We examine electron and phonon heat transport in metals, in the temperature range near to or above the Debye temperature, where it is generally assumed that phonon component is negligible for metals, an assumption that has not been subjected to rigorous experimental verification, particularly at the nanoscale, due to difficulties in direct measurement of thermal conductivity. Experimental evidence suggests that the venerated Wiedemann-Franz law breaks down at the nanoscale. I will describe our experimental results, theory based on the Boltzmann equation to describe our observations, and necessary corrections to Wiedemann-Franz.

February 24 - How Physicists Help to Treat Cancer in Radiation Oncology Departments

Prof. Arnold Pompoš
Dept. of Radiation Oncology
University of Texas Southwestern Medical Center

Pompos
Prof. Arnold Pompoš received his BS in Theoretical Physics from Charles University in Prague, Czech Republic in 1994 and his Ph.D. in experimental high energy physics from Purdue University in 2002.  He did postdoctoral research in high energy physics at The University of Oklahoma and his medical physics residency at The University of Nebraska Medical Center.  In 2009, Prof. Arnold Pompoš joined the faculty at the University of Texas Southwestern Medical Center in Dallas. His current research interest is in employing Monte Carlo computation and simulation technique to study energy deposition of accelerated carbon ions & energetic photons in tissue, micro-dosimetry on a molecular scale, nuclear activation of the irradiated tissue and its use for imaging, interaction of polarized DNA with polarized free radicals in irradiated tissue and energy deposition of plasma accelerated high energy electrons. More information about Prof. Arnold Pompoš and his research can be found at http://www.utsouthwestern.edu/findfac/professional/0,2356,106823,00.html

Abstract:
Ionizing radiation is dangerous, but if handled with caution, it helps many people to fight their cancer. In Radiation Oncology departments, we deposit energy to tumors via ionizing radiation. This process creates free radicals which then attack the cellular structures and cause cell death. It is challenging to cause tumor cells death only while keeping the healthy cells untouched. This presentation will be about physics of cancer treatment. I will cover the pros and cons of various radiation modalities as well as the research areas we are working on to maximize tumor eradication efficiency. 

World renowned astronomer and astrophysicist Dr. Jocelyn Bell Burnell visits Texas A&M University-Commerce, February 28 through March 4, 2011. 


Jocelyn BellDr. Jocelyn Bell Burnell (http://en.wikipedia.org/wiki/Jocelyn_Bell_Burnell) is best known for the discovery of pulsars (rotating neutron stars) in 1967 when she was a graduate student at the University of Cambridge in UK – work for which her thesis supervisor Dr. Antony Hewish was awarded a Nobel Prize in 1974.  The discovery, considered as the greatest astronomical discovery of the twentieth century by many people, has changed our understanding of stellar evolution and the fundamental make up of matter at extremely high densities. Dr. Bell Burnell is a Fellow of the Royal Society of London and a Foreign Associate of the US National Academy of Sciences. She has been President of the UK’s Royal Astronomical Society and has just completed her term as (the first female) President of the UK/Ireland Institute of Physics. She is currently a Visiting Professor at the University of Oxford and Mansfield College Oxford.  

Dr. Bell Burnell will be speaking to several groups during her stay.  The public is welcome to attend each of these events free of charge. 

 

Monday, Feb. 28 from 7:30-8:30 pm in the Planetarium Science Building room 125, Dr. Bell Burnell will give a talk on Astronomy and Poetry. The talk will be hosted by Dr. Kathryn Jacobs, Professor of English. As a hobby Dr. Jocelyn Bell Burnell collects poetry with space or astronomy themes, she has recently co-edited an anthology of poetry with an astronomical theme – ‘Dark Matter, Poems of Space’. During this talk she will be presenting poetry under the starry skies of the planetarium.

Tuesday, March 1 from 11:00am-12:00 noon in Innovations A of the Sam Rayburn Student Center, Dr. Bell Burnell will have Discussions with female faculty and students. The event is organized by Dr. Mary Hendrix, Vice President for Student Access and Success. Dr. Bell Burnell  is interested in women’s studies. She hopes that her presence as a senior woman in science will encourage more women to consider a career in science. “Dr. Bell Burnell will serve as a tremendous inspiration to our youngsters thinking of entering science and a great motivation for those still uncertain”, said Dr. Allan Headley, Dean of the Graduate School and Research. 

Tuesday, March 1 from 7:20-8:20 pm in room 214 of the Distance Education Center in the Agriculture-Industry Technology building, Dr. Bell Burnell will give a talk on A Reflection on the discovery of pulsars to the graduate class Physics 561: Astronomy Problems. The lecture is delivered via two-way video to TAMU-Commerce Metroplex Center at 2600 Motley Drive, Mesquite, Texas 75150. 

Wednesday, March 2 from 4-5 pm in Science Building room 127, Dr. Bell Burnell will give a talk on Will the world end in 2012? The astronomical evidence. This talk will be hosted by Dr. Kent Montgomery, Director of the Planetarium. A reception in her honor will be held from 3:30-4:00pm in the lobby of the Planetarium, everyone is invited.  What's all this about the end of the world in 2012? Just what is meant to happen, and how likely is it to happen? This talk examines the threats from space and explains how much truth there is in the suggestions that killer asteroids, lethal solar flares or the black hole at the center of the Milky Way (for example) could cause the end of the Earth.

Thursday, March 3 from 4-5 pm in Science Building room 127, Dr. Bell Burnell will give a physics and astronomy colloquium on Pulsars and extreme physics. This is an overview of the current state of our knowledge about Pulsars. The colloquium will be hosted by Dr. William G. Newton, a nuclear astrophysicist. 

UK and US universities and learned bodies have presented Dr. Bell with many awards including the 2010 Faraday Medal of the Royal Society of London, the Albert Michelson Medal of the Franklin Institute of Philadelphia, the J. Robert Oppenheimer Memorial Prize of the Center for Theoretical Studies in Miami, the Beatrice M. Tinsley Prize of the American Astronomical Society and the Herschel Medal of the Royal Astronomical Society.  Dr. Bell Burnell received a Commander of the Order of the British Empire (CBE) from Queen Elizabeth II in 1999 and was promoted to Dame Commander of the Order of the British Empire (DBE) in June 2007. 

March 3 - Nuclear Astrophysics Seminar

12noon-1:00pm,  Science 103

Nuclear Symmetry Energy Project

Prof. Betty Tsang
National Superconducting Cyclotron Laboratory
Michigan State University

TsangBetty Tsang is a professor at the National Superconducting Cyclotron Laboratory at Michigan State University. She received her PhD in Nuclear Chemistry at the University of Washington, Seattle. After graduation, she worked as a postdoctoral fellow at the NSCL and has been working there since 1980. She is a fellow of the American Physical Society and received the Heinz R. Pagels Human Rights award in 2000. Betty Tsang’s current research interests include experimental investigation of the density dependence of the symmetry energy and the study of nucleon-nucleon correlations in exotic nuclei. More information of her research can be found at http://www.nscl.msu.edu/~tsang/
Abstract:
Symmetry energy is the penalty energy a nucleus has to pay when the number of protons and neutrons are different. It is an essential ingredient in determining nuclear masses and the properties of objects with extreme ratios of neutrons and protons. These exotic objects include nuclei that are near the limit of existence and astrophysical objects such as neutron stars. As the symmetry energy and the nuclear density are different at the center and at the surface of a nucleus, the exact relationship between symmetry energy and nuclear matter density, known as the asymmetric term of the nuclear equation of state, is of intense interest to the nuclear physics community. 

March 10 - Global Warming - How bad is it? What can we do?

Prof. Wolfgang Bauer
Michigan State University

BauerProf. Wolfgang Bauer was born in Germany and obtained his Ph.D. in theoretical nuclear physics from the University of Giessen in 1987. After a post-doctoral fellowship at the California Institute of Technology, he joined the faculty at Michigan State University in 1988 and became a University Distinguished Professor there in 2007. He has worked on a large variety of topics in computational sciences, from high-temperature superconductivity and supernova explosions to biophysics, but has been especially interested in relativistic nuclear collisions. He is probably best known for his work on phase transitions of nuclear matter in heavy ion collisions. In recent years, Dr. Bauer has focused much of his research and teaching on issues concerning energy, including fossil fuel resources, ways to use energy more efficiently, and, in particular, alternative and carbon-neutral energy resources. He has been serving as the chairperson of the Department of Physics and Astronomy at MSU since 2001, as well as the founding Director of the Institute for Cyber-Enabled Research since 2009. More information about Prof. Wolfgang Bauer and his research can be found at http://www.pa.msu.edu/~bauer/
 
Abstract:
During the last century of burning fossil fuels for our energy needs we have increased CO2 level in our atmosphere by more than 30% over the highest levels during the previous half million years. Since CO2 is a greenhouse gas, this will have consequences, some of which are already measurable in form of rising global temperatures.  The central question is how to mitigate these effect by switching away from a fossil-fuel powered economy, but without giving up on our living standards. I will argue that this can be done, and that it can be done in a way that provides strong growth to our economy.

Special Nuclear Astrophysics Seminar 
12noon-1:15pm, Friday, March 11, 2011, Science 103 (lunch will be provided)

The Role of Deformation and Isovector Pairing on the Nuclear Symmetry Energy

Dr. Ian Bentley
Department of Physics
University of Notre Dame

BentleyDr. Ian Bentley received his BS in physics with Astrophysics Option from New Mexico Tech in 2004 and his Ph.D from the University of Notre Dame in May 2010 under the guidance of Prof. Stefan Frauendorf. He is currently a postdoctoral associate at Notre Dame and an adjunct assistant professor at the Department of Physics and Astronomy at Indiana University South Bend. 
Abstract:
In nuclei near the N = Z line, the linear coefficient in symmetry energy, as determined from experiment, has been seen to fluctuate. These fluctuations are often attributed to a combination isovector and isoscalar pairing. We have found that careful choice of deformation and a purely isovector interaction can account for the experimental observation. Schematic calculations using an isovector Hamiltonian, including several level systems solved exactly by means of diagonalization provide insight on the role of deformation. Several level calculations using Nilsson levels, which are a function of deformation, reproduce the general characteristics observed with slight modification of experimentally determined deformation parameters.

Special Nuclear Astrophysics Seminar 
4;00-5:00pm, Friday, March 21, 2011, Science 103

Massive neutron stars and the equation of state of matter at high densities

Dr. Ang Li
Texas A&M University-Commerce
and
Xiamen University

Ang LiDr. Ang Li received her Ph.D in nuclear theory from Lanzhou University in 2007. 
She is currently a Visiting Research Scientist at TAMU-Commerce and an Associate Professor at Xiamen University, China. She has been working on the equation of state of isospin-asymmetric nuclear matter and properties of neutron stars.
Abstract
The appearance of exotic phases in (proto)neutron star interior is studied. The possible transition from hadron to quark phase is studied within the density dependent mass quark model, and the kaon condensation within a standard chiral model at finite temperature. In both cases a microscopic approach is adopted for dense hadron matter. From the study of the possible coexistence between the two phases it is found that both hyperons and quarks may completely suppress the kaon degree of freedom. We also conclude that the most massive neutron stars must have a center with more than hyperon/nucleon matter, one containing a core consisting of strongly interacting quark matter.

March 23, 2011

Use of light to manipulate the structure and function of proteins

Prof. Lorenzo Brancaleon
Department of Physics and Astronomy
University of Texas at San Antonio

lorenzoDr. Lorenzo Brancaleon received his Laurea Degree  in Physics from the University of Parma in 1991 with the thesis entitled “Development of a Photoacoustic Calorimetry Instrument for the Investigation of Biomolecules”. In 1997 he received his PhD in Physics from the same University with a dissertation entitled “Photophysics of Tryptophan and Tryptophan-containing peptides”. From 1996 to 1998, he was a Research Associate at the Steacie Institute for Molecular Sciences of the National Research Council in Ottawa (Canada). From 1998 to 2000 he was an Assistant in Physics at the Massachusetts General Hospital and an Instructor at Harvard Medical School in Boston, MA. From 2000 to 2003 he was appointed as Photophysicist at the Scottish Photodynamic Therapy Center and the Photobiology Unit of Ninewells Hospital in Dundee (UK). During the same period he was a honorary lecturer at the University of Dundee and the University of St. Andrews (UK). In September of 2003 he joined the faculty at the Department of Physics and Astronomy at The University of Texas at San Antonio (UTSA). He is currently Associate Professor and Chair of the Graduate Program in Physics at UTSA. Dr. Brancaleon career has developed in and around the field of Molecular Biophysics. His investigations are currently centered around two main research lines (i) the conformational effects of photoactive dyes on proteins and (ii) the properties of biomolecules at the interface with ferroelectric thin oxide films. He has 34 peer reviewed manuscripts and over 40 presentation at international conferences. His group has an excellent reputation for undergraduate and graduate research training especially those of underrepresented groups.      
Abstract: 
The functions of proteins depend on their interactions with various ligands and these interactions are controlled by the structure of the polypeptides. If one can manipulate the structure of proteins, there is a chance to modulate their function. The issue of protein structure-function relationship is not only a central problem in Biophysics, but is becoming clear that the ability to “artificially” modify the structure of proteins could be relevant in fields beyond the biomedical area to provide, for instance, light-responses in proteins which would not possess such properties in their native state. The seminar will present an overview of various methods, the current status of the use of laser-induced conformational changes of proteins and a summary of the findings obtained in our group. Our investigations show that visible irradiation of two porphyrin-type, light-activated drugs with different physical-chemical properties, is capable of prompting unfolding of globular proteins. The unfolding can be as extensive as to involve over 15% of the structure of the polypeptide. Our results show that, contrary to what would be expected for porphyrin-type molecules the photoinduced unfolding is not mediated by the formation of singlet oxygen and in fact does not require the presence of diffusing molecular oxygen at all. This suggest a direct intermolecular charge transfer mechanism from the porphyrin to the protein that prompts this one to change conformation.

March 31, 2011

Probing the high density matter in heavy ion collisions

Prof. Che-Ming Ko
Department of Physics and Astronomy and the Cyclotron Institute
Texas A&M University


KoProfessor Ko received a B.Sc. degree from Tunghai University in Taiwan, a M.Sc. degree from McMaster University in Canada, and a Ph.D. from the State University of New York at Stony Brook. Before joining the Texas A&M faculty in 1980, he did research work at McMaster University, Max-Planck Institute for Nuclear Research, Michigan State University, and Lawrence Berkeley Laboratory. He received the Alexander von Humboldt Senior Distinguished Scientist Award in 1995 and the Texas A&M Association of Former Students Distinguished Research Award in 2004, and he is a Fellow of the American Physical Society. Currently, his research interests include theoretical studies of 1) nuclear symmetry energy effects in heavy ion collisions with rare isotopes, 2) signals and properties of the quark-gluon plasma in relativistic heavy ion collisions, and 3) particle production in hadronic reactions. His publications can be found in SPIRES <http://inspirehep.net/author/profile/C.M.Ko.2> . His research is supported by the National Science Foundation and the Robert A. Welch Foundation. 
 
Abstract: 
Heavy ion collisions provide the possibility to produce in the laboratory the dense nuclear matter that exists inside a neutron star and the quark-gluon plasma that is believed to have existed during the early universe. Because of its short lifetime, the dense matter produced in heavy ion collisions cannot be studied using external probes. Instead, its properties are inferred from its decay product. Significant progress has been made during the past two decades in understanding the properties of the dense matter formed in heavy ion collisions from studying particles produced in these collisions. This knowledge has enhanced our understanding of not only the physics of strong interaction but also many astrophysical phenomena such as the neutron star properties and how matter is formed from the primordial quark-gluon plasma during the early universe.  In this talk, I will review some of these progresses. For heavy ion collisions at low and intermediate energies such as at MSU and TAMU, I will present the constraints that have been obtained on the equation of state of asymmetric nuclear matter of unequal proton and neutron numbers. For heavy ion collisions at high energies such as at GSI and AGS, I will describe how the nuclear matter equation of state at high densities has been determined. For heavy ion collisions at relativistic energies such as at SPS and RHIC, I will review the evidence for the formation of the quark-gluon plasma and the information on its properties. For ultra-relativistic heavy ion collisions at LHC, I will discuss the possibility of studying exotic charmed hadrons in order to address some longstanding questions in hadron physics.  

April 7, 2011

How Things Break

Prof. Michael Marder
Department of Physics and Center for Nonlinear Dynamics
University of Texas at Austin

MarderProf. Michael Marder is a member of the Center for Nonlinear Dynamics, internationally known for its experiments on chaos and pattern formation, and for many years ranked #1 in the nation by US News and World Report. He is involved in a wide variety of theoretical, numerical, and experimental investigations. He specializes in the mechanics of solids, particularly the fracture of brittle materials. He has developed numerical methods allowing fracture computations on the atomic scale to be compared directly with laboratory experiments on a macroscopic scale. He is currently investigating fracture and deformation of polymeric materials. As Associate Dean for Science and Mathematics Education in the College of Natural Sciences, Michael Marder is co-director of UTeach, the University program for preparation of secondary mathematics and science teachers, is helping to introduce active learning techniques into undergraduate teaching, and helps oversee the national expansion of UTeach.  
Education:  
1986                Ph.D. (physics), University of California,  Santa Barbara
1982                A.B., Summa cum Laude (physics and mathematics), Cornell University
Experience:
2007--              Associate Dean for Science and Mathematics Education,  College of Natural Sciences
2000--              Professor of Physics
1998-2007       Director, Special Projects Office, College of Natural Sciences
1994-2000       Associate Professor of Physics, University of Texas, Austin 
1988-1994       Assistant Professor of Physics, University of Texas,Austin
1986-1988       Research Associate, James Franck Institute, University of Chicago
1983-1986       Research Assistant, UC Santa Barbara
University of Texas Affiliations: Center for Nonlinear Dynamics, Department of Physics, Science and Mathematics Education Graduate Program, Center for Mechanics of Solids, Structures, and Materials
Honors: 
2010                Joe and Bettie Branson Ward Excellence Award
2008                Elizabeth Shatto Massey Award for Excellence in Teacher Preparation
2008                American Physical Society Outstanding Referee
1996                Exxon Education Foundation 
1993                Alcoa Foundation 
1989                Sloan Foundation Fellow
Service:
Divisional Editor, International  Journal of Fracture
Selected Recent Publications: 
Condensed Matter Physics, Second Edition (Wiley, 2010)
Research Methods for Science (Cambridge, 2011)
 
Abstract:
Few properties of materials have been more important throughout history than their resistance to failure. However there was little scientific understanding until the middle of the 20th century, when a series of large-scale disasters made it essential to develop a theory of fracture. After reviewing the  history of fracture mechanics, with a focus on airplane safety, I will turn to some more recent topics, including instabilities in dynamic fracture, supersonic ruptures, and the tearing of graphene.

April 14, 2011

Balancing the Baryon Budget in Groups and Clusters of Galaxies

Prof. Ann Zabludoff
Department of Astronomy and Steward Observatory
University of Arizona

zabludoffDr. Ann Zabludoff is currently an Associate Professor of Astronomy and Associate Astronomer at the University of Arizona's Steward Observatory.  She is a graduate of the Massachusetts Institute of Technology (S.B. in Physics, S.B. in Mathematics) and Harvard University (Ph.D. in Astronomy).   Before joining the faculty at University of Arizona, she was a Carnegie Post-Doctoral Fellow at the Observatories of the Carnegie Institution in Pasadena, CA and a Hubble Post-Doctoral Fellow at the University of California, Santa Cruz.  Her work focuses on questions of galaxy formation and evolution, the evolution of large-scale structure, and the distribution and nature of dark matter.  More information about Prof. Zabludoff and her research can be found at http://atropos.as.arizona.edu/aiz/Home.html .
Abstract:
Stars that lie *outside* of galaxies are a significant part of the stellar baryon content of galaxy clusters and groups.  This result has consequences for the baryon budget of high mass halos and its relationship to the universal baryon fraction measured from the cosmic microwave background radiation. These "intracluster stars" also affect the chemical enrichment of clusters in previously unexplored ways, because they inject metals directly into the gaseous intergalactic medium as they age.  Finally, the kinematics of intracluster stars can be used to constrain the underlying mass profiles of clusters, particularly within the central 100 kpc, where predictions differ depending on the nature of the dark matter particle.  I will review our work characterizing the properties of intracluster stars, discussing whether baryons are missing on the scales of clusters and groups, whether it is possible to account for the high metal content of the intracluster medium, and what the mass profiles of the largest bound systems in the universe could tell us about dark matter.

April 21, 2011

Cosmic Dust Bunnies and Laboratory Dust Crystals: An introduction to complex plasma research

Prof. Lorin Matthews
Department of Physics and Center for Astrophysics, Space Physics, and Engineering Research
Baylor University

MathewsDr. Lorin Matthews graduated from Baylor University with a B.S. and Ph.D. in Physics in 1994 and 1998, respectively. She worked for Raytheon Aircraft Integration Systems from 1998-2000 in the Flight Sciences Department, where she was the lead vibroacoustics analyst on projects such as NASA's SOFIA (Stratospheric Observatory for Infrared Astronomy). In 2000, she joined the faculty at Baylor University where she is an assistant professor of physics and Associate Director of CASPER, the Center for Astrophysics, Space Physics, and Engineering Research..  Her areas of research include theoretical and experimental complex plasmas as well as hypervelocity impact studies.  Her theoretical research focuses on numerical simulation of N-body systems in complex plasmas, including fractal aggregation of micron-sized dust in protoplanetary disks, the dynamics of Saturn’s F Ring, and dynamics of dust crystals.  Her experimental research in complex plasmas is concerned with dynamics, stability, and phase changes in dust crystals, coulomb clusters, and dust strings.
 
Abstract:
Plasma, consisting of ions, electrons, and neutral particles, is a ubiquitous component of the universe.  Dust is also a common component, and when it is immersed in a plasma, it is termed a dusty or complex plasma.  The dust ions and electrons collide with the dust grains and cause them to become charged.  Thus the dust grains not only interact with gravitational fields, but also with electrostatic and magnetic fields. Complex plasmas can be found naturally in nebular clouds, the clouds surrounding developing protostars and protoplanets, the ephemeral rings around planets, in cometary tails, and even around earth.  Dusty plasmas are also a byproduct of the plasma processing of silicon wafers for computer chips.  Since the dust component can ruin the features being etched on the chips, dusty plasmas are purposely created in the lab to study their basic characteristics to learn how to control and exploit them.  In the last fifteen years, experimental dusty plasmas have become an increasingly interesting research topic due to the dust’s ability to self-organize. This talk will give an overview of the basic physics of dusty plasmas and the current numerical and experimental research being conducted at CASPER, the Center for Astrophysics, Space Physics, and Engineering Research, at Baylor University.

May 5, 2011

Physics of White Dwarf Supernovae

Prof. Frank Timmes
School of Earth and Space Exploration and the High Performance Computing Institute
Arizona State University

timmesDr. Frank Timmes is a Professor in, and Associate Director of, the School of Earth and Space Exploration (SESE) at Arizona State University (ASU). He is also Director of the High Performance Computing Institute at ASU, and a Scientific Editor for the Astrophysical Journal. Frank's research interests include supernovae, with emphasis on their progenitor evolution, explosion, nucleosynthesis, and spectra; cosmic chemical evolution, the evolution of every isotope at every point in spacetime; gamma-ray astronomy, particularly from radioactive isotopes; high performance computing, with an accent on multi-scale, multi-physics fluid flows; and astrobiology, with attention to creation and delivery of bioessential elements to habitable planets. More information about Prof. Frank Timmes and his research can be found at http://sese.asu.edu/person/frank-timmes
 
Abstract:
The recent "New Worlds, New Horizons" 2010 Decadal report identified "What are the progenitors of Type Ia supernovae and how do they explode?" as a science frontier question to address in the next decade.  These thermonuclear supernovae play a central role in astrophysics as premier distance indicators for probing the cosmic expansion history, as direct probes of low-mass star formation rates at high redshift, and as key contributors to iron-group abundances in the cosmos. In this talk we'll explore some recent developments in uncovering the unknown progenitor system(s), their explosion mechanism(s), and observable signatures in their nucleosynthesis, light-curves, and spectra. 

Colloquia and Seminar Archive

Quick Links

Need an update?

To request a change to this page or to request access to make changes yourself, email helpdesk@tamuc.edu.