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| September, 2007 | |
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Abstract: Dr.Selvaggi is a graduate of the UT Medical Branch. He has been practicing Family and Geriatric Medicine for almost 30 years. Interestingly, since he was an undergraduate student at UT-Austin Dr. Selvaggi has been very interested in physics. In particular, he has been pursuing some of his ideas related to Special Relativity and Quantum Mechanics in his spare times. More recently, Dr. Selvaggi has spent more time doing physics research and started doing some experiments to test his ideas. In this talk, Dr. Selvaggi will share with us his ideas and possibly some preliminary results of his experiments. He also welcomes comments and suggestions from all participants at the seminar. |
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Abstract: Neutron stars are one of the most exotic objects in the universe. Matter in their cores is compressed to huge densities ranging from the density found in nuclei to an order of magnitude higher. Understanding properties of matter under such extreme conditions of density (and pressure) is still far from complete and represents one of the most important but also challenging problems in modern physics. These properties are reflected in what is known as the nuclear equation of state, which is the relationship between pressure and density (and some other state variables), and is the most important input for solving the neutron star structure equations. After briefly reviewing our previous work on static (non-rotating) neutron stars, I will concentrate on our most recent results on rotating neutron stars with a particular emphasis on rapid rotation. Impact of (rapid) rotation on neutron star properties and thermal evolution will be discussed. |
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Abstract: Guided ion beam tandem mass spectrometry techniques are introduced and by using energy-resolved collision-induced dissociation an accurate measurement of the O?H dissociation enthalpy of phenol D298(C6H5O?H) = 361 +- 4 kJ/mol is determined. |
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Abstract: In the recent years taking images became easy and inexpensive in medicine, industry and science. Es a consequence, the number of digital images is growing tremendously. The industrialized countries are adding every year hundred of billions to the image collections. Thus the problem for image databases development and management is vital and attracts the attention of mathematicians, computer scientists, biologists, physicists, medical and other experts. Following this trend a number of image databases were launched in medicine, industry and science. They could be a powerful tool in the hands of the science experts providing an excellent opportunity for studying objects, observing phenomena or scientific laws. To reach these goals a set of tools is needed to let the user extract objects' or phenomena's features subject of interest. The present talk will introduce approaches capable of extracting geometric features such as convex hull, the number and the area of boundary concavities, and corners. Active contour and active concavity models are developed on the base of the geometric heat differential equation and monotonic vector forces. To validate the theoretical concepts a set of experimental results are given through the presentation. An application of the convex hull illumination problem to search space partitioning is illustrated at the end of the speech. |
| October, 2007 | |||||||||||||||||||||
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Abstract: The mechanism that leads to high-temperature superconductivity remains an open question in condensed-matter physics despite intense study for more than two decades. We introduce an SU(4) model for cuprate systems having many similarities to dynamical symmetries known in nuclear structure physics. Analytical solutions in three dynamical symmetry limits of this model are found: an SO(4) limit associated with antiferromagnetic order; an SU(2) limit with d-wave pairing order; and an SO(5) limit that may be interpreted as a doorway state between the antiferromagnetic order and the superconducting order. With a broken SO(5) expressed by the coherent states under constraint of the parent SU(4) symmetry, the model is capable of describing quantitatively the cuprate phase diagram and the pseudogap states that are crucial in explaining why cuprate systems that are antiferromagnetic Mott insulators at half filling become superconductors through hole doping. |
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Date : October 11 Time : 4-5pm Place : Science 127 |
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Abstract: The annual meeting of the American Physical Society, Texas Section, will be held in College Station this year. |
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Abstract: The colloquium will use this simulation as a paradigm for doing computational physics by emphasizing the importance of making the computational process subordinate to the physics of the problem. The talk will begin with a discussion on symplectic integrators where Hamilton's equations dictate the most natural numerical algorithms for solving classical dynamics problems. Next, solving the imaginary time Schr�dinger equation introduces the distinction between time-reversible and time-irreversible equations, with the latter requiring forward time step algorithms. Solving the imaginary time Gross-Pitaevskii equation with a rapidly rotating anisotropic trap then leads to vortices nucleation and giant vortex formation. |
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| November, 2007 | |
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Abstract: (a) and the research in the surface science lab at TAMU-Commerce (4:00-4:30). |
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Abstract: Motivated by a desperate request from two of his former students to guide them in the construction of a set of �tuned� woodblocks to be used in a percussion recital, the author undertook a theoretical analysis and an experimental investigation of the acoustics of an instrument of innocuous simplicity, the orchestral woodblock. Instead of a boring straightforwardness, he found that in this lowly instrument is a fascinating demonstration of the physics of flexural waves, the subtlies of the resonances of rectangular air ducts, the coupling of dissipative systems, as well as, an exhibition of the mechanical properties of wood, all encompassing several unsolved problems. In the process the author has discovered that the woodblock comprises two coupled systems�a plate idiophone and a slot resonator, each with its unique and remarkable features. The lecture will provide a colorfully illustrated introduction to the subject of the acoustics of percussion instruments for the undergraduate and graduate physics student but will also be of interest to non-specialists, all of whom will find that the apparent simplicity of this neglected instrument belies the richness of its acoustics. |
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Abstract: Numerous advances in magnetic resonance imaging (MRI) hardware and imaging techniques have allowed imaging scientists to transition MRI from a means of obtaining anatomic images with exquisite soft tissue contrast to a means of assessing a variety of non-invasive functional changes. Fast and ultrafast imaging techniques allow for the assessment of changes in rates of proton diffusion, changes in oxyhemoglobin/deoxyhemoglobin ratios, and changes in microvascular volume, flow, and permeability. Such techniques are beginning to make significant contributions to the non-invasive early assessment of novel therapeutic regimens and to image-guided therapies. High field strength whole-body imaging systems (3-Tesla and higher) enhance many of these functional imaging capabilities as well as non-invasive spectroscopy capabilities. This seminar will focus on recent technical advances in MRI and will highlight selected applications in image-guided therapies and non-invasive early assessment of novel oncologic therapies. |
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Abstract: String theory is roughly speaking based on the premise that, unlike quantum field theory, the fundamental quantum objects are not pointlike. So rather than electrons, positrons, quarks, neutrinos, and photons being pointlike, i.e. mathematically zero-dimensional, string theory considers the implications if such objects really were physically extended (and in fact having tension), i.e. the fundamental objects were mathematically one-dimensional. In this talk we will touch on some of the (physical and mathematical) ideas of string theory, proceeding in a semi-historical way. There are many beautiful applications of mathematics within string theory, and we will touch on some of them. |
| December, 2007 | |
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Abstract: 3:00-3:10, Bailey, Taylor C. |