By Tunna Baruah, Department of Physics, UTEP

Density functional theory is one of the most widely used method to calculate electronic properties of materials. DFT is known as a ground state theory. A description of excited states is necessary to describe most of the physical phenomena. Although time-dependent DFT method is widely used to describe the excited states, it is shown to fail for charge transfer states. In this talk I will discuss our DFT based method to describe the excited states particularly the charge-transfer states. Applications of this method for various types excitations such as core excitations, valence excitations, charge transfer excitations will be discussed. The possible improvements on this method will also be presented. We are interested in materials for renewable energy sources. One such promising molecule is a triad of carotenoid, porphyrin and fullerene. This triad shows interesting properties which can be exploited to achieve molecular scale organic photovoltaics. In the second part of the talk applications on the carotenoid-porphyrin-C60 molecular triad will be discussed.


Wednesday, November 18, 2009 at 4:30 pm in PSCI Rm 115

 

Density functional theory (DFT), in which the physically observable electron  density plays the role of basic variable instead of the wavefunction, has emerged  as a powerful tool for study of ground state properties of materials at the quantum mechanical level.  In fact, it has now become the method of choice in electronic structure calculations.  This is  primarily due to its ability to describe the underlying physics at sufficient accuracy as well as due to its efficiency. Nonetheless, numerous efforts are being put to further enhance the efficiency of DFT models to extend their domain of applicability. In this talk, I will describe some of our collaborative efforts on the development of grid-free implementation of the DFT[1]. The formulation, parameterization, and the performance of appraisal of our approach will be discussed.  This approach has allowed us to study nanosystems such as fullerenes, nanocrystals, quantum dots, nanotubes
containing up to two thousand atoms with moderately large triple zeta quality Gaussian basis set. Its applications such as the study of quantum size effects in dipole polarizability of carbon fullerenes,
optical gaps of diamond clusters, prediction of an infinite family of stable icosahedral boron fullerenes, structural stability of boron nitride cages and nanotubes, optical spectra of carbon fullerenes will be described.

1)       R.R. Zope and B. I. Dunlap, Chapter 9 in
  "Multiscale Simulation Methods for Nanomaterials",  John Wiley & Sons, Inc. (2008).

Wednesday Nov. 11 at 4:30pm in PSCI Rm 115

 

By Dr. Alexandros Gezerlis
University of Washington

Cold atomic gases provide a fascinating physical setting that constitutes a testbed of many-body theories. Neutron stars are compact objects that bring together aspects of nuclear physics and of astrophysics. Both cold Fermi atoms and neutron matter are systems which are very strongly paired, i.e. the pairing gap is of the order of the Fermi energy. Several many-body schemes have been devised in an attempt to accurately describe the strong coupling regime. In this talk, I will first describe why these two physical systems can and should be tackled together, and then discuss recent results on the equation of state, the pairing gap, and other observables that we have calculated using a microscopic ab initio method.

Wednesday, November 4, 2009 at 4:30 pm in PSCI Rm 115

Refreshments will be served
 

By Dr. Laura Paulucci
Instituto de Astronomia, Geofisica e Ciencias Atmosfericas
Universidade de Sao Paulo, Brazil

The strange quark matter hypothesis has been studied for more than twenty years. If strange quark matter is indeed stable, there could be important implications for Astrophysics. Among the most stimulating ones is the possibility of conversion of ordinary nuclear matter in strange quark matter in the interior of neutron stars due to the extremely high densities reached in the core of these compact objects. Processes such as the merger in neutron star binaries systems and supernova could eject lumps of strange quark matter, termed strangelets, in the interstellar medium. In this way, strangelets could be a component of the cosmic ray flux. In this seminar, I will discuss strangelets' passage through the interstellar medium and the possibility of reaching the Earth neighborhood. Estimates of the low energy flux of strangelets that could be trapped in the terrestrial magnetosphere are given. Also, the interaction of these particles with nuclei in the Earth atmosphere is analyzed with the aim of providing better understanding of the possible observational signatures.

Wednesday Oct. 28, at 4:30 pm in PSCI 115
 

By Vivian Incera, Department of Physics, University of Texas at El Paso


Dynamical Symmetry Breaking (DSB) is the occurrence of spontaneous symmetry breaking via nonperturbative quantum effects. Electrical superconductivity, chiral symmetry breaking in Quantum Chromodynamics, and color superconductivity, are all well-known examples of DSB. A strong enough external magnetic field may influence the occurrence of DSB in quite different ways. It may just destroy DSB, as it happens in the case of electrical superconductivity, it may actually trigger DSB, as in the phenomenon of Magnetic Catalysis; it may change the symmetry of the ground state, as it does in the magnetic phases of color superconductivity, or it may enhance the DSB, as in the case of chiral symmetry breaking in QCD. In this talk I will discuss the phenomenon of DSB in various theories of fermions in the presence of a magnetic field. The astrophysical relevance of the results will be outlined.

Wednesday, October 14, 2009 at 4:30 pm in PSCI Rm 115


 

Dr. Marian Manciu, Physics Department, University of Texas at El Paso

Megavoltage X-ray sources are commonly used for therapy planning, and knowledge of their spectral distribution is important for accurate dose calculations. There are many methods that could provide reasonable estimations of Megavoltage X-ray spectra, when very accurate attenuation data or at least very good set of initial guesses of the spectra are available. We present here a novel method, which can be used for accurate Megavoltage spectral reconstruction without any prior knowledge of spectral distribution; the method performs well even when the available transmission data are affected by noise. The method is based on a search for a smooth function that minimizes the differences between measured and calculated attenuation data. The algorithm is compared with well-known existing algorithms, using computer simulated data, both error-free and containing added random Gaussian noise. The reconstructed spectra are subsequently used to calculate the transmission through 50 cm of bone, muscle or fat tissue. The method is also tested with attenuation measurement data for up to 50 cm of water.

Other Medical Physics research projects will be briefly discussed at the end of the talk.
 

Dr. Murat Durandurdu, UTEP Department of Physics

An understanding of the fundamental principles of materials at the atomistic level has become increasingly important in many fields of their applications. For the past few decades, computer simulations have played crucial roles in materials research. In this talk, I will present how ab initio techniques can be applied to study the behaviors of materials under high stresses and to predict the atomic structures of nanoscale materials.

When: 4:30pm. Where: Downstairs in PSCI Room 115. Refreshments will be served. 

For the next two weeks the Physics undergrads and grads are invited to attend special Physics Seminars where they will have the opportunity to learn first hand what the Physics Professors are doing in their research and the tasks they have available for students. Don’t miss this chance to find out what is going on in your department and what area is more appealing to you. The earlier you get involved in a research project, the better!

Seminar presenters will be:
Dr. Miguel Castro Colin
Dr. Murat Durandurdu
Dr. Rosa Fitzgeral
and
Dr. Jorge Lopez

For the next three weeks the Physics undergrads and grads are invited to attend three special Physics Seminars where they will have the opportunity to learn first hand what the Physics Professors are doing in their research and the tasks they have available for students. Don’t miss this chance to find out what is going on in your department and what area is more appealing to you. The early you get involved in a research project, the better!

First seminar presenters will be:
Dr. Vivian Incera
Dr. Efrain Ferrer
Dr. Tunna Baruah
Dr. Felicia Manciu
 

The Physics seminar series starts from Wednesday, Sept. 2. Our first speaker is Hector Noriega-Mendoza, Physics, UTEP.
Abstract: In 2009, astronomers around the world celebrate the International Year of Astronomy, four hundred years after Galileo used a telescope as a scientific tool for the first time in history to systematically explore the skies. I will discuss concrete examples of the role of the telescope a) as an instrument of discovery, b) as an excellent observational tool to test scientific theories and c) in terms of the challenges the largest ground-based instruments (New Generation Telescopes) and space observatories pose to modern technology. Telescopes of the non-optical astronomy and the different observational techniques will be briefly analyzed in the context of their applications to the hottest topics of modern astrophysics, such as extrasolar planets and the indirect observational evidence of black holes and dark matter.
Wednesday, Sept. 2 at 4:30 pm in Rm PSCI 115. Note the change in date and venue. Refreshments will be served. 

M. Castro-Colin, Dept. of Physics, UTEP

Quite often the generation of materials in a nanostructured manner will benefit from the availability of a master pattern with reasonable degree of stability. We look at a problem where zeolites, which are porous structures, represent a template to host nanostructured materials. The template, imposes a physical constraint that alters the typical properties associated to its bulk counterpart. Specifically it is discussed the structure of HgSe and Se nanostructured species, allocated in the pores of zeolites, with tubular as well spherical pore types. Overall structural information of the system is extracted from Rietveld refinement and that information is then used to carry out pair-distribution function (PDF) analysis upon the same structure, to disclose information underlying as a signal of diffuse character.

Friday, May 1 at 2:30 pm
PSCI Rm 208
 

By Ronald J. Tackett, Physics, UTEP

Magnetic nanoparticles have been the subject of intense research for the past few decades owing in large part to their current and potential applications in biomedicine and in the development of high-density magnetic storage media. Key to the functionality of these systems are microscopic structures and mechanisms that make these particles exhibit unique properties and behave differently from their bulk counterparts. Starting with a brief overview of magnetism, the presentation sets out to explore the fantastic changes in the magnetic properties that occur when the physical dimensions of materials become smaller than typical magnetic length scales. Among the first differences noticed arise when nanoscale ferromagnets are investigated. While the magnetic properties of bulk ferromagnets are governed by domain dynamics, as the material’s physical size is reduced through some critical length scale, the formation of multi-domain structures is no longer energetically favorable, and a new type of behavior known as superparamagnetism arises. While this superparamagnetic behavior is well understood in terms of thermally activated spin reversal over an energy barrier, many factors such as interactions between the nanoparticles cause deviations from this simple picture. The effects of these factors are investigated. In addition to these effects, the relation of nanoscale magnetics and its coupling to dielectric properties will be presented. Thirdly, a comparison of the effect of physical size constraints on magnetic ordering is presented as long-wavelength based magnetodielectric coupling is observed to vanish in nanoparticles of the same material. Finally, as consumer-driven technology grows, the need for a single material that can be altered for use in a wide variety of applications becomes increasingly more evident. It is with this motivation that a study of the tuning of the magnetic properties of nanoparticles becomes interesting. Investigations of methods to tune these characteristics will be presented.

Friday April 24
PSCI 208 at 2:30 pm 

By L. E. Murr, Department of Metallurgical and Materials Engineering, UTEP

Abstract: This seminar examines the microstructures and nanostructures for natural (mined) chrysotile asbestos nanotubes (Mg3 Si2O5 (OH)4) in comparison with commercial multiwall carbon nanotubes (MWCNTs), utilizing scanning and transmission electron microscopy (SEM and TEM). Black carbon (BC) and a variety of specific soot particulate (aggregate) microstructures and nanostructures are also examined comparatively by SEM and TEM. A range of MWCNTs collected in the environment (both indoor and outdoor) are also examined and shown to be similar to some commercial MWCNTs but to exhibit a diversity of microstructures and nanostructures, including aggregation with other multiconcentric fullerenic nanoparticles. MWCNTs formed in the environment nucleate from special hemispherical graphene “caps” and there is evidence for preferential or energetically favorable chiralities, tube growth, and closing. The multiconcentric graphene tubes (~5 to 50 nm diameter) differentiate themselves from multiconcentric fullerenic nanoparticles and especially turbostratic BC and carbonaceous soot nanospherules (~8 to 80 nm diameter) because the latter are composed of curved graphene fragments intermixed or intercalated with polycyclic aromatic hydrocarbon (PAH) isomers of varying molecular weights and mass concentrations; depending upon combustion conditions and sources. The functionalizing of these nanostructures and photoxidation and related photothermal phenomena, as these may influence the cytotoxicities of these nanoparticulate aggregates, will also be discussed in the context of nanostructures and nanostructure phenomena, and implications for respiratory health.

Friday April 17, 2009 at 2:30 pm
PSCI 208 

By Felicia Manciu, Department of Physics, UTEP

The aim of this talk is to demonstrate the usefulness of Raman scattering and infrared absorption techniques in probing the quality of, and determining structural modifications of materials, as well as in revealing interesting new phenomena. Two different combinations of organic/inorganic materials, which result from the synthesis of Maya pigments and from the growth inhibition of urinary calculi by herbal extracts, will be presented.

A fascinating aspect of Maya pigments is that despite environmentally harsh humidity and high temperatures they resist fading and they have unprecedented stability. In this investigation, we address the question of how an organic dye binds to the inorganic mineral palygorskite to form a pigment similar to Maya Blue. We also address how such binding might be affected by varying the proportion of dye relative to that of the mineral, and by varying the length of heating time used in preparation of the pigment. Our analysis by Raman and infrared absorption spectroscopies demonstrates the partial elimination of selection rules for the centrosymmetric indigo, and shows the disappearance of the indigo N-H bonding, as the organic molecules incorporate into the palygorskite material. Infrared data confirm the loss of zeolitic water and a partial removal of structural water after the heating process. Evidence of bonding between palygorskite and indigo through oxygen is revealed by both spectroscopic measurements.

Although a considerable number of investigations of urinary calculi have already been undertaken and many causes such as life habits, metabolic disorders, and genetic factors have been noted as sources that accelerate calculi depositions and aggregations, there are still plenty of unanswered questions regarding efficient inhibition and treatment mechanisms. Thus, in an attempt to acquire more insights, we propose here a detailed scientific study of kidney stone formation and growth inhibition based on a traditional medicine approach with Rotula Aquatica Lour (RAL) herbal extracts. A simplified single diffusion gel growth technique was used for synthesizing the samples for the present study. The unexpected Zn presence in the sample with RAL inhibitor, as revealed by XPS measurements, explains the inhibition process and the dramatic reflectance of the incident light observed in the infrared transmission studies. Raman data indicate binding of the inhibitor with the oxygen of the kidney stone. Photoluminescence results corroborate to provide additional evidence of Zn-related inhibition.

March 27 at 2:30 pm
PSCI 208
 

By Cristian E. Botez, Department of Physics, UTEP

The nature of the microscopic modifications that accompany the heating-induced three-order-of-magnitude proton conductivity jump in phosphate-based solid acids has been under dispute for almost two decades. Some attribute this behavior to polymorphic structural transitions to so-called superprotonic phases, while others associate it with dehydration and chemical decomposition. Clarifying the chemical composition and crystal structures of the phases present in these materials at high temperatures is important in order to propose realistic scenarios for proton migration, and, eventually, uncover the microscopic mechanisms responsible for their superprotonic behavior.
We carried out laboratory and synchrotron x-ray diffraction experiments aimed at investigating the structural and chemical modifications undergone by CsH2PO4 (CDP) and RbH2PO4 (RDP) upon heating. Our data demonstrate that the room-temperature (RT) monoclinic (P 21/m) CDP phase transforms into a cubic (P m 3 m) polymorph at exactly the same temperature where the superprotonic jump was observed, and prior to the initiation of dehydration. Using high-pressure methods we managed to stabilize the superprotonic CDP phase and uncover details of its crystal structure. For RDP we found a transition from the RT orthorhombic (I -4 2 d) structure to an intermediate-temperature monoclinic (P 21/m) phase, whose crystal structure is almost identical to that of monoclinic CDP. This remarkable similarity opens the possibility that that the dynamics responsible for the high-temperature superprotonic behavior of these compounds does not depend on the cation type, but on the symmetry of the crystal structure.

PSCI 208, 2:30 pm March 13 

By Sergio Flores, Department of Physics, UTEP

A functional understanding of Newton’s second law as a vector equation requires that students be able to reason about vectors. In this presentation, we present data describing students’ conceptual difficulties with vector addition and subtraction, and with vector quantities such as force, acceleration and tension. These data suggest that after traditional instruction in introductory physics, some students do not recognize the vector nature of these quantities. Other students who do not have the required procedural knowledge to determine net force or acceleration, and are therefore unable to reason qualitatively about Newton's second law. We describe some specific procedural and reasoning difficulties we have observed in students’ use of vectors. In addition, we describe modifications to laboratory instruction in mechanics that we designed on the basis of our research into student understanding. These modifications were intended to improve students’ understanding of vector addition and subtraction and to promote student use of vectors when solving mechanics problems. Finally, we describe initial measures of the effectiveness of these modifications.

Date and time : Friday, March 6 at 2:30 pm
Place: PSCI 208

 

Juan Ferret, Department of Philosophy, UTEP

In recent years there have been proposals (DuBois 2002) to show that the state of some physical systems necessarily entail the inclusion of initial and final conditions. Also, following the line of reasoning promoted by Einstein integrating Galilean Relativity with electromagnetic phenomena, Carlo Rovelli argues for relational quantum mechanics (RQM) (Rovelli 1996) a proposal where there is no preferred absolute quantum system (even at the moment of measurement) and that observation of properties or behavior of a system must be necessarily performed by a separate system. In RQM, the state of a system S is relative to another system O that is observing S.

My goal is to integrate the basic premise that all physical systems are fundamentally anticipatory (and not just a few of them) and that RQM follows conceptually from this idea of anticipation and the relativity of motion. I begin showing the fundamental relationship between the physical state of the system and its energy, first in a simple case in classical mechanics and then in a more complex case in quantum mechanics. The first case serves, first, to remind us that energy is arbitrary and so is the state of the system, and second, that the role of potential energy is precisely one of anticipation of interaction with another system at the boundaries of the system with its environment. Then I offer a brief analysis of relational quantum mechanics (RQM) and how it shows the need to consider systems as inherently anticipatory. This is so since the relational and relative state of systems indicate that a system is ontologically given by another system. Hence, a system will be relational and inherently anticipatory because of the potential interaction from a given reference frame. This addition of the relation aspect of a system foments the ontological fundamental nature of system interactions.

Friday Feb 27 at 2:30 pm
PSCI 208 

By Ramon Ravel, Department of Physics, UTEP

Recently, there has been a considerable increase of interest in areas related to material behavior at extreme conditions: Mbars pressures and ultra-high strain-rates (> 108 s-1). This is in part due to the emergence of high-energy laser facilities such as the National Ignition Facility (NIF), scheduled for completion later this year and which will be able to create extremely high pressures utilizing Mega-Joule laser pulses. Additionally, the development of intense light sources like the Stanford Linac Coherent Light Source (LCLS) will be capable of providing in-situ time-resolved X-ray diffraction diagnostics with sub-picosecond resolution. These facilities will allow the study of material properties at conditions until now inaccessible to experiments. The response of a solid to such high strain-rates and pressures while unexplored experimentally can be studied using a wide variety of constitutive models and computational techniques. Advances in large-scale computer architectures and in massively parallel computational methodologies have made possible the simulation of high strain-rate phenomena at length and time scales which continue to inch closer to current experimental resolutions. In this talk we will examine the challenges in achieving Mbar pressures and highlight results from selected large-scale simulations of isentropic and shock loading phenomena in solids and liquids.

Friday at 2:30 pm, Feb 20
PSCI 208 

By Vladik Kreinovich and Roberto Araiza, Computer Science Department, UTEP.

Abstract: Not all mathematical solutions to physical equations are physically meaningful: e.g., if we reverse all the molecular velocities in a breaking cup, we get pieces self-assembling into a cup. The resulting initial conditions are "degenerate": once we modify them, self-assembly stops. So, in a physical solution, the initial conditions must be "non-degenerate". A challenge in formalizing this idea is that it depends on the representation. For example, we can use the non-relativistic Schroedinger equation to explicitly represent the potential function V(r)=F(W,...) in terms of the wave function W and its derivatives. The new equation dF/dt=0 is mathematically equivalent to the Schroedinger equation but now V(r) is in the initial conditions and thus, has to be restricted by the non-degeneracy condition. An even more radical is a situation with a general relativistic scalar field f. For this situation, we describe a new "equation" which is satisfied if and only if f satisfies the Euler-Lagrange equations for some Lagrangian. So, similarly to Wheeler's cosmological "mass without mass", we have "equations without equations".


Time and place : Friday, Feb 13, 2:30 pm at PSCI 208.
Refreshments will be served. 

By Otto F. Sankey, Department of Physics, Arizona State University, Tempe AZ

Abstract:  Viruses are the simplest “life” form. These parasites reproduce by borrowing the machinery of their host cell. Many are pathogenic to plants, animals, and humans. Viruses possess an outer protein coat (capsid) that protects its genomic material that resides inside. We have developed a theoretical technique to model the very low frequency mechanical modes of the viral capsid with atomic resolution. The method uses empirical force fields and a mathematical framework borrowed from electronic structure theory for finding energy states. The low frequency modes can be “pinged” with an ultra-short laser pulse and the aim of the light/vibrational coupling is to interfere with the viral life cycle. The theoretical work here is motivated by the recent work of Tsen et al. [2] who have used ultra-short pulsed laser scattering to inactivate viruses.  Coupled mechanical oscillation of other floppy biomolecules such as a complete ATP binding cassette (ABC transporter) will also be discussed.

Co-authors of this work are:  Dr. Eric Dykeman, Prof. Frank Tsen and Daryn Benson.

[1] E.C. Dykeman et al., Phys. Rev. Lett. 100, 028101 (2008).

[2] K-T. Tsen, et al.,  J. of Physics – Cond. Mat. 19, 472201 (2007).

 

Date and time: Friday, Feb 6 at 2:30 pm

 

By Dr. E. J. Ferrer, Physics Dept. UTEP.

Abstract :
In this colloquium I will discuss some of the fundamental challenges faced by the physics at the beginning of the XXI Century. The role of Supersymmetry in Cosmology and Astrophysics, the problem of Dark-Energy, Extra-Dimension issues, among others, will be addressed at a general level. The colloquium is intended to motivate the students to become involved in the great discovering adventure of the XXI Century.
Date and time : Jan 30, 2009 at 2:30 pm
Place : PSCI 208
Refreshments will be served.  

by C. V. Ramana
Metallurgical and Materials Engineering
University of Texas at El Paso
One of grand challenges facing the scientific community in the 21st century is the discovery, design, and development (3D) of new materials to meet the requirements of enhanced performance, stability, long-shelf life, and environmental safety. New phases and structures of materials await discovery, particularly at the nanoscale dimensions, and novel fabrication & manufacturing strategies remain to be explored in order to address these challenges. However, we need to understand what should we do with our fundamental science and, somehow, if we are restraining the principles that we have learned for a long time. The present talk will focus on engineering novel ‘metal and oxide’ materials for application in electronic and energy devices. Engineering the epitaxial structure of Fe, using an atomic Ti layer, on Al substrates will be discussed. The emphasis is to show how ‘order’ can be promoted at a system, which is well-known for intermixing and ‘disorder.’ The results obtained on the growth, microstructure, and electronic/electrochemical properties of V-, Ni-, and Co-based oxides for application in energy storage devices will also be discussed. Debating questions, such as “can physicists and engineers restrain the laws of fundamental science,?” will be opened up for discussion while explaining the implications and significance of the experimental results.

Date : Friday, Nov 21, 2008
Time : 2:30 pm
Place: PSCI 208
 

By Jack Chessa
Assistant Professor
Department of Mechanical Engineering
The University of Texas at El Paso

Conventional finite element methods have become synonymous with simulation in industry. A primary reason for its success has been the remarkable variety of problems that the method has been applied. Still there exist several areas where the finite element method exhibit poor convergence. Typically, these problems involve “rough” features. By “rough” we are referring to features that are discontinuous or nearly discontinuous. Example problems involving such difficulties include: damage and fracture, shear localization, interfacial and heterogeneous problems, multiphase flow, cavitation, fluid structure interaction, boundary layer resolution, and explicit shock tracking.This talk will discuss one approach to remedy this deficiency, enriched finite element methods, and particularly the extended finite element method (X-FEM), in computational solid and fluid mechanics problems. This class of numerical methods seek to endow the standard finite element method with the ability to reproduce fields that are problematic to piecewise continuous polynomial basis approximations, thereby recovering the theoretical convergence rates for conventional finite element methods. The method has shown remarkable range of applicability; originally developed specialized to linear elastic fracture mechanics the method has developed into a very powerful and systematic method for dealing with arbitrary strong and weak discontinuities in C0 and C1. The talk will first give an overview to the X-FEM method and discuss its theoretical underpinnings, such as the partition of unity method. Then several applications outside of the realm of linear elastic fracture mechanics will be given. Also, approaches to some recently open issues will be discussed such as blending elements and time integration. And finally, the application of these methods to a rather complex computational material design problem, ultra-high temperature ceramic composites, will be presented to illustrate how such approaches can be employed in a multiscale design problem.

Date: Friday, Nov. 7, 2008
Time: 2:30 pm
Place: PSCI 208 

By Pavel Solin
Department of Mathematical Sciences
University of Texas at El Paso

The Finite Element Method (FEM) is the most widely used
numerical technique for the solution of Partial Differential
Equations (PDE). These equations describe various physical
processes on macroscopic scale, such as heat transfer, flow,
electromagnetics, coupled problems, etc. The method is based
on a subdivision of the computational domain into polygons
(or curved polygons) where the solution is approximated
using polynomials. Standard FEM uses piecewise-linear or
piecewise-quadratic approximations. The hp-FEM is an advanced
version of FEM capable of achieving much faster convergence
than standard FEM by combining optimally elements of variable
diameters (h) and polynomial degrees (p). Automatic adaptivity
(local mesh refinement and coarsening) is essential for accurate
resolution of important physical phenomena of interest. For
stationary problems (whose solution does not depend on time),
many adaptive FEM algorithms have been around for a long time.
A few adaptive hp-FEM algorithms for stationary PDE problems
emerged in the last two decades. The solution of transient
(evolutionary) PDE problems, however, is much more difficult
and space-time adaptive FEM algorithms are extremely hard to
find. Prior to our work, no such algorithms have been available
for the hp-FEM.

In this talk we present the first space-time adaptive
hp-FEM algorithm suitable for the numerical solution of
transient PDE and multi-physics PDE problems. We will
discuss main ideas of the new methodology and illustrate
it with numerical examples such as flame propagation,
two-component flow, thermally-conductive flow, microwave
heating, and others.

Date: Friday Oct. 31, 2008
Time: 2:30 pm
Venue: PSCI 208 

By Mario Borunda
Physics Department
Texas A&M University

Spintronics is where the two fundamental properties (spin and charge) of the electron are manipulated simultaneously. This field has already produced revolutionary applications in metallic systems such as high density hard drives and magnetic random access memory (MRAM). Yet, since most logic devices are built on semiconductors, the richest rewards (and challenges) are still to come. This talk will present: (1) An introduction to basic concepts of semiconductor spintronics, with a special emphasis on how spin-orbit coupling can electrically manipulate the spin of the carriers without the need for a magnetic field. (2) The challenges before spintronic devices. (3) Theoretical models that explain the anomalous Hall effect and the spin Hall effect. (4) The proposal of a spin-modulator device, based on the non-adiabatic geometric phase and tuning of the spin-orbit coupling.

DateL: Oct. 10, 2008
Time: 2:30 pm
Venue: PSCI 208
Refreshments will be served.  

By Jorge Lopez
Chair, Physics Department, UTEP

The isoscaling phenomenon was first observed in nuclear multifragmentation experiments and has become a hot topic as it could provide a probe of the nuclear equation of state to understand nuclear matter at extreme condition of isospin such as in neutron stars. The present work studies isoscaling using 1) classical molecular dynamics simulations, 2) percolation and 3) probabilistic arguments, and determines that isoscaling is a general phenomenon that can exist independent of the nuclear reaction, and it is expected to occur in disassembling systems with no more than fair sampling.

Date : Oct. 3, 2008
Time: 2:30 pm
Venue: PSCI 208
Refreshments will be served. 

By Leticia Velázquez
Director of UTEP Computational Science Program

Computational Science is an interdisciplinary program, crossing
departmental and college boundaries, that yields an integrated
knowledge-base for the effective solution of complex problems where computer usage plays a fundamental role. UTEP offers studies leading to degrees of a Doctor of Philosophy and Master of Science in Computational Science. During this talk, the program and its opportunities for creating a new generation of computational scientists will be described.
Date: 9/26/08, Friday
Time: 2:30 pm
Place: PSCI 208. Refreshments will be served.  

By Vladik Kreinovich (Computer Science Dept., UTEP), John McClure, (Metallurgical Dept., UTEP) and John Simmons, (Philosophy Dept., UTEP).

Why do we need theory? One of the purposes of science is to enable a user to predict, however, in the past, even when the user encountered a situation very similar to what has already been observed, it was not possible to find the corresponding record and simply recall what happened then (at least not possible in reasonable time). The only possibility was to extract, from the observed data, a simple dependence, and then use this dependence to predict the behavior in new situations. Nowadays, computers are very fast, and searches are so fast that there seems to be no need to derive any theoretical laws anymore: if we want to predict (e.g., predict the voltage), we can simply search through all the records. So maybe we do not need theory at all. In our presentations, we will describe this argument in detail, and give our opinion on whether the computer progress will indeed lead to the end of the theory as we know it.

Wednesday, September 10, 2008, 3:30 p.m., PSCI 208. 

PHYSICS OF GASES ADSORBED IN CARBONS
Our Guest Speaker:

Silvina M. Gatica
Howard University


Carbon nanotubes, buckyballs (C60) and materials with nanoporosity represent novel substrates for gas adsorption. This situation has attracted significant experimental and theoretical attention due to many possible practical applications as for example gas storage, gas separation and gas sensors. These studies resulted in a wide variety of interesting behaviors. In this talk I will review some of the properties of gases in these nanostructures that are results of computer simulations and model calculations. For example, Xenon adsorbed in an array of buckyballs form a honeycomb lattice gas with a lattice constant significantly larger than in most traditional surfaces. Gases adsorbed in carbon nanotubes form commensurate lattices or striped phases when adsorbed on the surfaces of a bundle.
Adsorption of gases is also used to characterize porous materials. Although for many gases the adsorption isotherms show nearly universal behavior, Hydrogen deviates from the universality showing much higher uptake, I will discuss an explanation to this phenomenon related to quantum rather than size effects.

Seminar Date: Friday, April 25, 2008
Time: 2:30
Place: Physical Science Building, room 208

Refreshments will be served
 

Dr. Alejandro de Lozanne, University of Texas, Austin, Texas
The 2007 Nobel Prize in Physics was awarded to Fert and Grünberg for the discovery of Giant Magnetoresistance. Magnetoresistance is fairly common since many metals show a drop in resistance when a magnetic field is applied, but the effect is small, typically less than 1%. In 1988 two independent groups led by Fert and Grünberg reported changes in resistance as large as 100%, which were therefore called “giant” magnetoresistance (GMR). An amazing fact is that this discovery went from the lab to a mass-produced consumer product (the hard disk in your computer) in only a decade. A much bigger effect was reported in 1994 on manganese oxides. Since the effect was 127,000%, it was named colossal magnetoresistance (CMR). I will give a brief history of these effects and show our results on several manganese oxides obtained with home-made magnetic force microscopes and scanning tunneling microscopes.
Friday, April 11, 2:30 p.m., PSCI 208
Refreshments will be provided 

Dr. Alfredo Aranda, University of Colima The Large Hadron Collider (LHC) is expected to start operations this summer and will start looking for the Higgs. Finding it and determining its properties will give us precise information regarding the electroweak sector of the Standard Model and its extensions. In this talk I will review the status of our understanding regarding the unification of the electromagnetic and weak interactions. I will present the main problems associated with the breaking of the electroweak symmetry and some of the ways people think the solution can be found. In particular I will discuss how one can solve some of the problems in the context of physics of extra dimensions.

Friday, March 14, 2:30 p.m., PSCI 208
Refreshments will be provided 

Dr. Alonso Gutierrez, Dept. Radiation Oncology, Cancer Research and Therapy Center, San Antonio, TX. The recent incorporation of radiological imaging with advanced radiation delivery has opened the door for new therapeutic approaches in cancer treatment. Among these is image-guided, intensity modulated radiation therapy (IG-IMRT). A novel form of IG-IMRT delivery is helical tomotherapy. The unique delivery geometry of helical tomotherapy permits the radiation shaping of conformal dose distributions to tumors while conformally avoiding critical normal structures. The inherent capabilities of helical tomotherapy not only allow for better modulation of the physical dose distribution but also open the possibility of modulating the biological dose. In principle, clinical implementation of IG-IMRT should improve the efficacy of radiation therapy through enhanced normal tissue sparing and significant biologically effective dose escalation. An overview of helical tomotherapy and novel clinical applications with helical tomotherapy are discussed.
Friday, March 7, 2:30 p.m., PSCI 208
Refreshments will be provided 

Dr. Russell R. Chianelli, Chemistry Dept., UTEP A study of a series of advanced materials that form nano-particulate “surface compounds” combining synthesis, synchrotron techniques and simulation is presented. Understanding of surface compounds is crucial in understanding and controlling the properties of new materials with important novel and energy applications. Generally, surface compounds are associated with high surface area or porous materials that can be described as nano-particles. The materials described are:
• Transition Metal Sulfide (TMS) Catalytic Materials: The TMS form surface compounds of the type MoS2-xCx. The TMS catalytic materials are crucial petroleum treating catalyst that remove pollutants and upgrade fuels.
• Organic/Inorganic Complex Materials: These materials based on ancient Mayan technology are surface compounds that interact organic molecules (indigo) at the surface of an inorganic compound (palygorskite) to form novel stable materials with novel and useful properties.
• Complex Asphaltene Molecules: These materials are complex aromatic/ parffinic “nano-ellipsoids” that occur in all petroleum and tar materials. They are remnants of the origin of the petroleum and huge problems for the refining industry. But they represent a class of materials that may become new thermo-electric or semi-conducting materials.
These materials require interdisciplinary interaction across physics, chemistry and engineering to fully understand and exploit. The approach of synthesis, experiment and theory is applied to both fundamental and practical application of these materials. In addition, progress in advancing the commercial application of these materials through UTEP start-up companies will be discussed.

Wednesday, March 5, 4:30 p.m., PSCI 208
Refreshments will be provided 

M. R. Pederson, Naval Research Laboratory Molecular polarizabilities in molecules are interesting due to the role they play in many physical, chemical, and biological processes. In weakly interacting molecular materials, the polarizabilities are responsible for long-range attractions due to dipole-/monopole- induced dipole interactions or London interactions. In ionic and molecular crystals, the Clausius-Mossotti relation and extensions relates the materials dielectric constant to the polarizabilities of the molecular systems. In biology or biomimetic materials, light-induced charge transfer interactions are of interest and the excited states of these systems are significantly changed by a polarizable medium. A method for extracting the electronic polarizability tensor, infrared intensities and Raman spectra will be reviewed. Also the relationship between second-harmonic vibrational polarizabilities and molecular infrared intensities will be demonstrated. To assess the accuracy of density-functional theory, Recent applications to the calculation of electronic and vibrational polarizabilities of molecules and systems of molecules will be presented. Finally a method that uses DFT-extracted polarization data will be outlined which allows one to determine variations in charge-transfer energetics in polarizable media. Applications discussed include fullerene clusters and crystals, water clusters and recent calculations on van der Waal’s attraction parameters in simple molecules..
Friday, February 29, 2:30 p.m., PSCI 208
Refreshments will be provided 

Igor Vasiliev, New Mexico State University Theoretical modeling of nanoscale structures presents major challenges to computational methods used in quantum-chemistry and condensed matter physics. The challenges are mainly related to the complex structure, composition, and the lack of three-dimensional space periodicity of nanomaterials. The complexity of nanoscale materials necessitates the use of efficient numerical techniques in conjunction with massively parallel computing. This colloquium will focus on recent advances in theoretical methods for predicting the electronic, structural, and optical properties of materials at the nanoscale and sub-nanoscale. A particular attention will be given to ab initio techniques based on static and time-dependent density functional theory. The flexibility of the density functional computational approach will be illustrated by its application to a wide variety of nanoscale systems, including metallic nanoparticles, functionalized and cross-linked carbon nanotubes, carbon-metal heterostructures, and polymer-nanotube composites.
Friday, February 22, 2:30 p.m., PSCI 208
Refreshments will be provided 

Miguel Castro Colín, Physics Dept., UTEP Frustration in an antiferromagnetic material can be measured taking advantage of one of the properties of neutrons, the net magnetic moment, as they interact with matter. The example discussed corresponds to one where spin-spin correlations in a spinel are suppressed by the crystal structure. Neutron spectroscopy clearly reveals this aspect and yields information about short range correlations within the material, both temporally and spatially.
Wednesday Feb. 13, 4:30 p.m., PSCI 208
Refreshments will be provided 

*** OPEN TO ALL SCIENCE AND ENGINEERING MAJORS ***
Arthur S. Edison, University of Florida The National High Magnetic Field Laboratory is the only national laboratory in the United States dedicated to magnet science and technology development. The talk will provide an overview of the biological applications at the Advanced Magnetic Resonance Imaging and Spectroscopy facility at the University of Florida (http://www.mbi.ufl.edu/facilities/amris/). Summer undergraduate research opportunities at the NHMFL and collaborative research opportunities with interested faculty members will be discussed.
Friday Feb. 9, 12:30 p.m., PSCI 220
Pizza and refreshments will be provided read more ...

or What do hornplayers do with their right hands, anyway?

Dr. Brian W. Holmes, Dept. of Physics, San Jose State University It is easy to think of a trumpet as a device for transmitting sound into a room. Actually, very little of the sound in a trumpet escapes to the outside. Most of the sound in a trumpet stays inside, where it forms standing waves that draw energy from the player's lips. I will show why sound traveling in a tube tends to reflect from an open end. Brass musical instruments consists of a mouthpiece, a conical leadpipe, a cylindrical section, and a flared bell. I build a trumpet to show the acoustical significance of these parts. Brass instruments rely on valves (or, in the case of the trombone, a slide) to extend the length of the tubing. In this they are unlike the woodwinds, which rely on side holes. In the era before valves, horn players learned to augment their meager supply of open notes by partially or completely blocking the air column with their right hands. Even through the modern horn relies on valves (rather than on this hand technique), horn players still keep their hands in the bell. I demonstrate the acoustical and musical significance of the right hand in horn playing.
Tueday Feb. 5, 4:30 p.m., PSCI 115
Refreshments will be served 

Dr. Jorge A. López, Physics dept., UTEP The phenomenon of isoscaling can help us elucidate the role of isospin in the nucleus. In this study, the origin and evolution of isoscaling is studied using classical molecular dynamics, percolation and probabilistic arguments. An ever-present non-thermal source of isoscaling is identified through these studies, and a possible experimental realization of this baseline effect is extracted from data.
Friday Jan. 25, 2:30 p.m., PSCI 208
Refreshments will be served 

Dr. Gabriela Gonzalez, for the LIGO Scientific Collaboration Gravitational waves are expected from many different astrophysical sources: brief transients from violent events like supernova explosions and collisions of neutron stars and black holes, coalescence of compact binary systems, continuous waves from rotating systems, and stochastic signals from cosmological origin or unresolved transients. The LIGO gravitational wave detectors have achieved unprecedented sensitivity to gravitational waves, and future upgrades promise to open a window to a new observational science. I will describe the present status of the detectors, describe the results obtained from the data taken already, and discuss the possibilities for the near future.
Friday Nov. 16, 2:30 p.m., PSCI 208
Refreshments will be served 

Dr. Luis F. Rodriguez, Center for Radioastronomy and Astrophysics Universidad Nacional Autónoma de México. The stuff of science fiction sometimes seems to materialize in the real world of science. Over the years, astronomers have found sources, galactic and extragalactic, that appear to eject matter that moves in the plane of the sky at speeds that exceed the speed of light. But we also know from Einstein's theory of Relativity that Nature forbids objects from surpassing this limit speed. The apparent paradox finds a happy solution that is allowing the astronomers to gain understanding in what happens near black holes when they eject blobs of gas at tremendous speeds.
Monday Nov. 12, 4:30 p.m., PSCI 208
Refreshments will be served 

Dr. Ben Zeidman, Argonne National Lab Experiments involving electroproduction of K+ mesons on light nuclei and Photodisintegration of deuterium are described and the results interpreted in terms of the quark model, conservation laws, and elementary mechanics.
Tuesday Nov. 6, 4:30 p.m., PSCI 208
Refreshments will be served
 

Dr. Thomas Cahill, Distinguished Emeritus Professor of Physics, Applied Science, and Environmental Studies, University of California at Davis
Dr. Cahill heads the UC Davis DELTA Group (for Detection and Evaluation of Long-range Transport of Aerosols), a collaborative association of aerosol scientists at several universities and national laboratories. The DELTA Group has made detailed studies of aerosols from the 1991 Gulf War oil fires, volcanic eruptions, global dust storms, Asia and -most recently— studies of dust from the collapsed buildings of the World trade Center. Dr. Cahill found unprecedented amounts of very fine particles, silicon, sulfates, and metals. These studies and other topics will be presented in this talk.
Wednesday Nov. 7th, 4:30 p.m., PSCI 208
Refreshments will be served 

Dr. Boris Kiefer, New Mexico State University The modeling of the Earth’s interior is constrained by surface and space observations. However, the interpretation in terms of Earth’s structure is complicated by competing effects of phase, composition and temperature. Mineral physics allows the separation of these contributions and helps understand the transport of mass, momentum, and energy across the interior of our planet. Density functional theory (DFT) is used to gain insights into the properties of iron and its spin state in (Mg1-x,Fex)2SiO4 - wadsleyite which is the most abundant mineral in the upper part of the Earth’s transition zone (410-520 km depth). Understanding the intra-site partitioning of iron in this mineral may affect our understanding of properties such as, density, elasticity, melting temperatures and hydrogen uptake in the upper part of the transition zone. A second application of DFT addresses hydrogen transport into the Earth’s lower mantle along subduction zones. The elastic signature of the symmetrization of the hydrogen bond in Phase D will be discussed and the results suggest that elastic anisotropy is an observable that can be used to determine the hydrogen distribution in the mantle.
Friday Nov. 2, 2:30 p.m., PSCI 208
Refreshments will be served 

Dr. Christina Allen, Instituto de Astronomía, Universidad nacional Autónoma de México
The galactic orbits of 48+6 globular clusters in a Milky-way-like barred galaxy are presented. The influence of the bar on tidal radii and destruction rates is discussed, and some major discrepancies between theory and observations – along with possible solutions – are pointed out.
Friday, October 12, 2007, 2:30 p.m., PSCI 208
Refreshments will be served
 

Dr. H. C. Rosu, Universidad Autónoma de San Luis Potosí, México
Microtubules (MT) are basic nanometric protein filaments in the bulk of all eukariotic cells. A brief review of the following issues in the MT biophysics will be presented:
(i) Kinklike excitations along the MT walls
(ii) Supersymmetric version of Dogterom-Leibler single MT polymerization model
(iii) Comments on the recent speculation about the MT transistor-like properties
Friday, October 5, 2007, 2:30 p.m., PSCI 208
Refreshments will be served 

Dr. Alfredo Aranda, Visiting Professor, UTEP.
The salient features of the Standard Model of Particle Physics and its impressive success will be presented with a detailed description of its main limitations and shortcomings. Several of the most important theoretical attempts made so far in order to extend it will be examined. Finally a recent proposal based on a minimalistic approach that can lead to verifiable and thus discardable models will be discussed. A specific example involving neutrinos and the Higgs boson will be presented.
Friday, September 17, 2007, 2:30 p.m., PSCI 208
Refreshments will be served 

Yong P. Chen, J. Evans Attwell-Welch Postdoctoral Fellow, Rice University
Quantum coherence in condensed matter is often associated with superfluids and superconductors. In this talk, two experiments will illustrate that quantum coherence is important in macroscopic insulators. The first one deals with a Bose-Einstein condensate (BEC) of 7Li atoms subjected to a disordered optical potential made by laser speckle. The second one is related to a semiconductor double quantum well with low interlayer tunneling but strong interlayer Coulomb interaction subjected to a transverse magnetic field.

Wednesday April 18, 2007, PSCI 220 11:00 AM, Refreshments will be served. 

Dr. Charles F. Kennel, Director, Environment and Sustainability Initiative, University of California, San Diego

This week the Physics seminar will piggyback on the Millennium lecture:

President Diana Natalicio and The Center for Environmental Resource Management cordially invite you to attend A UTEP Millennium Lecture

Dr. Kennel was born in Cambridge, Mass., and was educated in astronomy and astrophysics at Harvard and Princeton. He then joined the UCLA Department of Physics, conducting research and teaching in space plasma physics and astrophysics, and chaired the department for three years. He eventually became UCLA’s Executive Vice Chancellor, its chief academic officer. From 1994 to 1996, he was Associate Administrator at NASA and Director of Mission to Planet Earth, the world’s largest Earth-science program. His experiences at NASA convinced him to devote the rest of his career to Earth and environmental science. He was the Director of Scripps Institution of Oceanography and Vice Chancellor of Marine Sciences at the University of California, San Diego. He now directs the UCSD Environment and Sustainability Initiative – an all-campus effort embracing teaching, research, campus operations, and public outreach – and is a distinguished professor of atmospheric sciences at Scripps. Monday, April 9, 2007, 4:00 p.m. Undergraduate Learning Center, Room 106, Reception to Follow Presentation 

Dr. Jeff Terry, Illinois Institute of Technology
Synchrotron radiation sources have been used to study materials since the late 1960s. Studies using synchrotron sources have allowed us to answer questions ranging from what is the electronic structure of a given material to what is the geometric structure of proteins? This presentation will cover the basics of photoelectron spectroscopy and x-ray absorption spectroscopy using synchrotron radiation as the excitation source. This will be done using examples from core level spectroscopy of silicon surfaces, valence band spectroscopy of metallic actinides, determination of environmental contaminants, and theoretical modeling of the data.
Friday, April 6, 2007, 12:00 p.m., PSCI 220, Pizza will be served to those that RSVP to Terry at 747-7527
 

Dr. Javier Miranda, Instituto de Física, Universidad Nacional Autónoma de México
The emission of X-rays after the excitation with photons, electrons, or light ions (such as protons or deuterons), has been extensively studied. However, when heavier ions are used as primary radiation to induce this effect, other phenomena occur that are not present or are not as relevant as in the other cases. They include, for instance, the creation of short-lived molecules, the capture of electrons from the target atom by the incoming ion, and a strong increase in the multiple ionization of the target atom. Normally, the ionization cross sections are higher as compared to those of photons, electrons, or light ions. Furthermore, when thick targets are irradiated with heavy ions, there is a larger probability to create defects in the material, and also a higher stopping power in the target material. All these differences make the study of the X-ray production by heavy ions a problem not fully understood, and far from being applied in an extensive manner to the characterization of materials. In this talk, an explanation of the basic phenomena is presented, as well as a description of possible uses of the emission of X-rays by the impact of the heavy ions, as an extension of the traditional method Particle Induced X-ray Emission (PIXE).
Friday, March 30, 2007, 2:30 p.m., PSCI 208, (refreshments will be served)
 

Dr. Rajeev K. Pathak, Department of Chemistry and Quantum Theory Group, Tulane University, New Orleans, Louisiana

In quantum mechanics, the uncertainty principle leaves the coordinate and the momentum spaces enigmatically disjoint. There is no ‘joint’ phase-space one-electron probability distribution in quantum mechanics. Several searches for a joint (one-electron-) probability density, including that of Wigner are not necessarily positive semidefinite. It will be demonstrated that the Zhao-Parr description of the Kohn-Sham Density-Functional-Theory (DFT) enables one to estimate the electron momentum density starting from the coordinate space electron density. Thus, a connection between two apparently unconnected experimental situations, viz. coherent, elastic photon scattering by atoms (leading to the electron density) with an inelastic Compton scattering process (yielding the electron momentum density) can be established.
Monday, March 19, 2007, 4:00 p.m., PSCI 208, (refreshments will be served)
 

Mr. Manuel Ramos, MASE, UTEP
The talk will report a collaboration with T. Effio, S. Pamidi, Ulf Trociewitz, and Justin Schwartz of the National High Magnetic Field Laboratory, Tallahassee, Florida which studied the dependence of the properties of high temperature superconductors on the texture in Bi2Sr2CaCu2O8+x (Bi2212)/AgX superconductor wires induced during heat treatment in a background magnetic field.
Wednesday Feb. 28, 2007, 1:30 PM, PSCI 220
Refreshments will be available
 

Dr. Alexis de Saint-Ours, University of Paris 8
We will examine various accounts of time in classical physics, relativity and quantum gravity. Time will either appear as not existing at a fundamental level, or instead inherently becoming. We will try to show that these questions are related to the idea of spatialization and examine whether or not the definition of time as an ordered sequence of events might be a proper way of understanding it.
Friday Feb. 23, 2007, 2:30 PM, PSCI 208
Refreshments will be available 

Dr. Juan Ferret
Department of Philosophy, University of Texas at El Paso
Measurement has been a rather sticking conceptual point for the foundations of quantum physics, and many interpretations exist to account for what happens when a quantum mechanical system is measured or strongly ‘interacts’ with another system. After a brief summary of these positions, I will introduce Relational Quantum Mechanics, an interpretation developed by Carlo Rovelli and others, as a compelling solution to the problem of measurement. At the end, I will present a critique of Relational Quantum Mechanics and offer a variation of Rovelli’s position by incorporating Hughes’ concept of quantum event and Omnès’ account of decoherence.
Friday Feb. 16, 2007, 2:30 PM, PSCI 208
Refreshments will be available 

Arthur S. Edison, University of Florida
The National High Magnetic Field Laboratory is the only national laboratory in the United States dedicated to magnet science and technology development. The talk will provide an overview of the biological applications at the Advanced Magnetic Resonance Imaging and Spectroscopy facility at the University of Florida. Summer undergraduate research opportunities at the NHMFL and collaborative research opportunities with interested faculty members will be discussed.
NHMFL website: http://www.magnet.fsu.edu/
AMRIS website: http://www.mbi.ufl.edu/facilities/amris/
Friday Feb. 9, 2007 at 12:00, PSCI 220, Pizza will be provided

 

Dr. Arthur S. Edison
Department of Biochemistry & Molecular Biology, University of Florida
Nuclear magnetic resonance is a critical tool in natural product identification. To reduce sample preparation and the amount of starting material a new 600 MHz 1-mm NMR probe made from high temperature superconducting (HTS) material has been developed. Using this probe, samples of about 1 mL of the secreted venom of a single walkingstick insect have been analyzed. The ability to examine very small amounts of material by NMR has allowed new questions to be addressed about chemical biodiversity and opens up numerous new opportunities for drug discovery using natural products.
Friday Feb. 9, 2007, 2:30 PM, PSCI 208
Refreshments will be available 

Dr. L. J. Martínez-Miranda, University of Maryland
The interaction of nanometer particles with organic materials is important because of the use of nanoparticles in many applications. We have looked to the interaction between nanometer particles of different sizes with sm-A liquid crystals, the phase of the cell membranes, concentrating in the functionalization compound that surrounds the particles. We have found that the liquid crystal responds to the nanometer particles differently depending on the functionalization or surface termination compound and have developed a phenomenological model to explain the differences that we see. Further analysis of our X-ray scattering scans shows preliminarily that for particles whose size is comparable to the size of the liquid crystal two different behaviors arise. We discuss some of the consequences of these.
Friday January 26, 2007, 10:30 AM
Physical Science Building 220
Refreshments will be served 

Electroweak symmetry breaking is one of the key problems in particle physics. After an introduction to the problem I will discuss some of the recent ideas in the direction of a possible solution. In particular, I will explore solutions created in the scenario of extra dimensions.
Friday, Dec. 8, 2006, PSCI 220, 2:30 –31:30 

Dr. Ben Zeidman will describe the history of quark-related experiments conducted at SLAC and jefferson lab. Additionally he will interview students interested in the summer program of Argonne National Lab near Chicago.
Pizza will be provided
Wed. Nov. 29, 2006, PSCI 220, 12:30 – 1:30 

Center for Biomolecular Modeling, Milwaukee School of Engineering
Tuesday, November 28, 2006, 1:00 pm to 2:150 pm, PSCI 213. 

Dr. Don Salisbury, Austin College
(A joint presentation from Physics and Philosophy Dept.)
An arbitrary choice of time in any solution of Einstein’s field equations of general relativity leads to a new, but presumably equivalent solution. This arbitrariness has suggested that time cannot be given an ontological significance and that temporal change is an illusion. On the other hand if a change does occur, is that change real? The historical overview of the temporal evolutionary problem in classical general relativity of Leon Rosenfeld, Peter Bergmann and Paul Dirac will be presented.
Friday, November 17, 2006, 2:30 pm to 3:30 pm, PSCI 208. 

Dr. Miguel Castro Colin, UTEP
Position and distance are fairly well defined parameters in the crystalline state, but such "simple definition" can not be readily made about gases or liquids. In the last two, X-ray scattering patterns exhibit the appearance of fluctuations, which are broad when compared with those typically obtained in crystalline matter, the so-called Bragg peaks. One frequent description of non-crystalline matter is made via the atomic distribution function, whose concept will be touched upon as well as the advantages that synchrotron sources represent in their study.
Friday, November 3, 2006, 2:30 pm to 3:30 pm, PSCI 208
 

Dr. Tunna Baruah, UTEP
In this talk calculations on a light-harvesting molecular triad composed of a fullerene, a porphyrin and a carotenoid polyene will be discussed. By calculating electronic structures, approximate excited states and respective dipole transition rates, we simulate charge transfer dynamics in a collection of the triad molecules exposed to an appropriate bath of solar photons. The resulting time constants associated with capture of solar radiation in the form of a charge-separated state have been determined. These results and future research directions will be discussed.

Friday, October 27, 2006, 2:30 pm to 3:30 pm, PSCI 208
 

The search for physics beyond that encompassed by the Standard Model has been a major research theme since the Standard Model was formulated. Cold and ultra-cold neutrons are ideal tools for testing the fundamental symmetries of the Standard Model interactions. I will describe upcoming experiments and opportunities to measure the electric dipole moment of the neutron, the correlation coefficients from the neutron beta-decay spectrum and the determination of the weak quark-quark interaction through neutron parity-violation.
Friday, October 20, 2006, 2:30 pm to 3:30 pm, PSCI 208
 

This talk will present a study of infrared and Raman spectroscopy in probing the quality and structure of nanomaterials, as well as in revealing interesting new physics. Optical characterization for Maya pigments and MoS2 nano-catalyst will be presented. In the last part of the talk, infrared characterizations of arsenic uptake by plant tissues and of semiconductor CdS nanoshells will be presented, and future research will be discussed.
Friday, October 13, 2006, PSCI 208, 2:30 pm—3:30 pm
 

Will discuss the thermodynamics of ultracold atoms confined in magnetic traps, such as those that are produced in current expriments with alkaline atoms. Since these systems are confined by external magnetic fields and not by rigid walls, it is shown that the hydrostatic pressure and the volume are no longer the appropriate thermodynamic variables for those systems. Instead, "new" variables which depend on the particular confining potential replace them. Detailed results for a 3D harmonic potential and for a quadrupolar one will be presented, and the "new" thermodynamics will be used to study the Bose-Einstein Condensation with and without interatomic interactions.
Friday, October 6, 2006, PSCI 208, 2:30 pm—3:20 pm
 

After a brief review of General Relativity and of the ideas of Kaluza and Klein for unifying gravity and electrodynamics, I will discuss several aspects of recent investigations into the possibility that our space time has more than 4 space-time dimensions, with emphasis on the motivations and problems of the various options. I will conclude with comments on model-building and the implementation of phenomenological constraints.
Friday, September 29, 2006, PSCI 208, 2:30 pm—3:20 pm
 

Centro de Ciencias Fisicas, UNAM
"Casimir effect for arbitrary materials: contributions within and beyond the light cone".
Friday, September 22, 2006, PSCI 208, 2:30 pm—3:20 pm