The Department of Physics has a long tradition of organizing and hosting the Physics Seminars. This weekly event series serves as a major window into the new and exciting world of modern physics. Invited speakers from all branches of physics have been giving Colloquia on our campus for students and faculty.
Physics Colloquium
Date |
Name |
Institucion |
Flyer |
Feb 7 |
Dr. Shahram Dehdashti |
The Technical University of Munich | |
Feb 14 |
Dr. Natalie Hinkel |
Louisiana State University |
|
Feb 28 |
Dr. Peter Craig |
Michigan State University |
|
Mar 7 |
Dr. Althea Moorehead |
NASA MSFC |
|
Mar 14 |
Dr. Adina Feinstein |
Michigan State University |
|
Mar 21 |
No colloquium (Spring break) |
|
|
Mar 28 |
Mr. Alejandro Garcia |
The University of Pennsylvania |
|
Apr 4 |
Dr. Robert Hynes |
Louisiana State University |
|
Apr 11 |
Dr. Hamed Ghaemidizicheh |
The University of Texas Rio Grande Valley |
|
Apr 18 |
No colloquium (Easter holiday) |
|
|
Apr 25 |
Dr. Knicole Colon |
NASA Goddard Space Flight Center |
|
May 2 |
No colloquium (COS research symposium) |
|
|
Date
|
Speaker
|
Institution
|
Title
|
Jan 26
|
Dr. Mircea Chipara
|
UTRGV
|
From Interface to Interphase
|
Feb 2
|
Mr. Richard Pomeroy
Mr. Richard Camuccio
Mr. Moises Castillo
|
UTRGV
|
|
Feb 9
|
Dr. Robert Blum
|
Rubin Observatory, Director for Operations
|
Rubin Observatory and the Legacy of Space and Time (LSST) |
Feb 16
|
Ms. Zoi-Lina Koutsogianni
|
The School of Chemistry in Aristotle University
of Thessaloniki, Greece
|
GREEN CHEMISTRY AND BIOMASS
VALORIZATION FOR THE PRODUCTION OF HIGH
ADDED VALUE CHEMICALS AND PRODUCTS
|
Feb 23
|
Dr. Andrea Delgado
|
ORNL
|
Crafting Generative Models & Unraveling High Energy Physics with Parameterized Quantum Circuits |
March 1
|
Dr. Anderson Winkler
|
UTRGV
|
Optimal Echo Time for fMRI in the Infant Brain |
March 22
|
Dr. Louis Dartez
|
Caltech (LIGO Hanford)
|
An Overview of Commissioning and Calibration Efforts During LIGO’s Fourth Observing Run |
April 5
|
Dr. Cesar Bonilla Diaz
|
Universidad Catolica del Norte de Chile
|
Searching for Physics Beyond the Standard Model |
April 12
|
Dr. Zhijun Qiao
|
UTRGV
|
Peaked solitons and beyond
|
Sep 6
|
Dr. Minsu Kim
|
Emory University
|
Understanding living organisms as dynamical systems: the dynamic property of antibiotic resistance in bacteria
|
Sep 13
|
Sergio Cantu
|
QuEra Computing
|
Quantum Computing: A Revolution is Coming
|
Sep 20
|
Mr. Devinda Pankaja
|
The University of Illinois at Urbana-Champaign
|
Insights into Back-Steps, Rotations, and Cargo-Size Effects of Kinesin Motility with MINFLUX
|
Sep 27
|
Dr. Harold Kim
|
The Georgia Institute of Technology
|
Measuring looping anisotropy of DNA
|
Oct 4
|
Dr. Mukremin Kilic
|
The University of Oklahoma
|
A Revolution in Stellar Astrophysics, and the Remaining Challenges
|
Oct 11
|
Dr. Mahdi Sanati
|
Texas Tech University
|
Studying the secondary electron emission from Cu (110) surface covered with various forms of carbon
|
Oct 18
|
Dr. Unnati Kashyap
|
Texas Tech University
|
Unveiling the accretion properties of low-mass X-ray binaries
|
Nov 1
|
Dr. Teresa Nieves-Chinchilla
|
The Goddard Space Flight Center (GSFC), NASA
|
Watching and Unravelling the Mysteries of the Sun
|
Nov 8
|
Dr. Socrates Munoz
|
Kansas State University
|
Simplicity as the Driving Force for Invention of Organic Reactions
|
Nov 15
|
Dr. Gloria Fonseca
|
NSF's NOIRLab
|
Mapping supermassive black hole growth with large scale optical surveys
|
Nov 22
|
Dr. Delaram Mirfendereski
|
The University of Texas Rio Grande Valley
|
The geometry of gauged (super)conformal sigma model
|
Date
|
Speaker
|
Institution
|
Title
|
---|---|---|---|
Jan 27
|
Aria Hajikhani, Bhawana Sedhai, Fargol Seifollahi
|
UTRGV, Physics
|
|
Feb 3
|
Dr. Laura Finzi
|
Emory University
|
|
Feb 10
|
Dr. Gisela Ortiz Leon
|
The National Autonomous University of Mexico
|
|
Feb 17
|
Dr. Aarran Shaw
|
The University of Nevada, Reno
|
|
Feb 24
|
Dr. Howard (Ho Wai) Lee
|
The University of California, Irvine
|
|
Mar 3
|
Dr. Carlos Handy
|
Texas Southern University
|
|
Mar 22
|
Dr. Hyeongjun Kim
|
UTRGV, Physics
|
|
Mar 24
|
Dr. Paul Selvin
|
The University of Illinois at Urbana-Champaign
|
|
Mar 31
|
Dr. Michael Poirier
|
The Ohio State University
|
|
Apr 14
|
Dr. Karen Masters
|
Haverford College
|
|
Apr 21
|
Dr. James (JC) Gumbart
|
The Georgia Institute of Technology
|
|
Sep 8
|
Dr. Rohan Naidu
|
MIT
|
|
Sep 12
|
Dr. Aspen X.-Y. Chen
|
University of Hong Kong
|
|
Sep 15
|
Dr. Hamed Ghaemidizicheh
|
UTRGV
|
|
Sep 22
|
Dr. Wilson A. Zuniga-Galindo
|
UTRGV
|
|
Sep 29
|
Dr. Aldo Batta
|
INAOE, Mexico
|
|
Oct 6
|
Dr. Sang Hak Lee
|
Pusan National University, Korea
|
|
Oct 13
|
Dr. Juan Hinestroza
|
Cornell University (Cancel)
|
|
Oct 20
|
Dr. Julie Vanegas
|
UTRGV
|
|
Oct 27
|
Dr. N. Scott Bobbitt
|
Sandia National Laboratories
|
|
Nov 3
|
Dr. Vishal Gajjar
|
UC Berkeley, and the Berkeley SETI Center
|
|
Nov 10
|
Mr. Andrés Cuella Vega
|
Industry
|
|
Nov 17
|
Dr. Mircea Chipara
|
UTRGV
|
Date
|
Speaker
|
Institution
|
Title
|
---|---|---|---|
Feb 1
|
Dr. Douglas Natelson
|
Rice Univ.
|
Noise reveals unusual pairs in cuprate superconductors
|
Feb 8
|
Dr. Zhijun Qiao
|
UTRGV, Math
|
Peakon, cuspon, and short pulse models generated through the negative-order integrable systems
|
Feb 15
|
Dr. Nicholas Dimakis
|
UTRGV, Physics
|
Electron Density Topological Analysis and its applications on adsorption
|
Feb 22
|
Dr. Soma Mukherjee
|
UTRGV, Physics
|
Detection of Gravitational Waves from Core Collapse Supernovae
|
Mar 1
|
Dr. Sanju Gupta
|
Western Kentucky Univ.
|
Science and Technology of Graphene-family Nanomaterials: Opportunities at the Grand Challenges of Energy-Water-Sensing Nexus
|
Mar 8
|
Dr. Mario Diaz
|
UTRGV, Physics
|
The future of the Universe:
Will we ever have a theory of everything?
|
Mar 22
|
Dr. Hyeongjun Kim
|
UTRGV, Physics
|
Single-molecule studies of how MORC protein functions and condenses DNA
|
Apr 5
|
Dr. Sarbajit Banerjee
|
Texas A&M Univ.-College Statoin
|
Mining Metastable Phase Space for New Function: Some Perspectives for the Design of Cathode Materials and Logic Circuitry
|
Apr 12
|
Dr. Stojan Rebic
|
PRL, Assoc. Editor
|
How to publish in Physical Review Letters
|
Apr 18
|
Dr. Matthew Benacquista
|
UTRGV, Physics, NSF
|
News from the NSF
|
Apr 26
|
Dr. Shervin Fatehi
|
UTRGV, Chemistry
|
Harnessing the intermolecular Coulombic decay mechanism for targeted energy transfer in solution
|
Aug 30
|
Dr. Volker Quetschke
|
UTRGV, Physics and Astronomy
|
Advanced LIGO’s third observing run has begun
|
Sept 6
|
Dr. Karen Martirosyan
|
UTRGV, Physics and Astronomy
|
Size- and Shape- Controlled Properties of Nanostructured Systems
|
Sept 13
|
Dr. Soumya Mohanty
|
UTRGV, Physics and Astronomy
|
Swarm intelligence in Gravitational Wave data analysis
|
Sept 27
|
Dr. Efrain Ferrer
|
UTRGV, Physics and Astronomy
|
Searching for the Inner Phase of Neutron Stars
|
Oct 4
|
TBD
|
||
Oct 11
|
Dr. Mircea Chipara
|
UTRGV, Physics and Astronomy
|
PHYSICAL ASPECTS IN POLYMER-BASED NANOCOMPOSITES
|
Oct 25
|
Dr. Ed Banigan
|
MIT, Physics, Institute for Medical Engineering and Science
|
|
Nov 1
|
Canceled
|
||
Nov 8
|
Dr. Juan Madrid
|
UTRGV, Physics and Astronomy
|
|
Nov 15
|
UTRGV Graduate Students
|
UTRGV, Physics and Astronomy
|
Colloquium 2019
Date | Speaker | Institution | Title |
---|---|---|---|
Feb 1 | Dr. Douglas Natelson | Rice Univ. | Noise reveals unusual pairs in cuprate superconductors |
Feb 8 | Dr. Zhijun Qiao | UTRGV, Math | Peakon, cuspon, and short pulse models generated through the negative-order integrable systems |
Feb 15 | Dr. Nicholas Dimakis | UTRGV, Physics | Electron Density Topological Analysis and its applications on adsorption |
Feb 22 | Dr. Soma Mukherjee | UTRGV, Physics | Detection of Gravitational Waves from Core Collapse Supernovae |
Mar 1 | Dr. Sanju Gupta | Western Kentucky Univ. | Science and Technology of Graphene-family Nanomaterials: Opportunities at the Grand Challenges of Energy-Water-Sensing Nexus |
Mar 8 | Dr. Mario Diaz | UTRGV, Physics | The future of the Universe: Will we ever have a theory of everything? |
Mar 22 | Dr. Hyeongjun Kim | UTRGV, Physics | Single-molecule studies of how MORC protein functions and condenses DNA |
Apr 5 | Dr. Sarbajit Banerjee | Texas A&M Univ.-College Statoin | Mining Metastable Phase Space for New Function: Some Perspectives for the Design of Cathode Materials and Logic Circuitry |
Apr 12 | Dr. Stojan Rebic | PRL, Assoc. Editor | How to publish in Physical Review Letters |
Apr 18 | Dr. Matthew Benacquista | UTRGV, Physics, NSF | News from the NSF |
Apr 26 | Dr. Shervin Fatehi | UTRGV, Chemistry | Harnessing the intermolecular Coulombic decay mechanism for targeted energy transfer in solution |
Aug 30 |
Dr. Volker Quetschke | UTRGV, Physics and Astronomy | Advanced LIGO’s third observing run has begun |
Sept 6 | Dr. Karen Martirosyan | UTRGV, Physics and Astronomy | Size- and Shape- Controlled Properties of Nanostructured Systems |
Sept 13 | Dr. Soumya Mohanty | UTRGV, Physics and Astronomy | Swarm intelligence in Gravitational Wave data analysis |
Sept 27 | Dr. Efrain Ferrer | UTRGV, Physics and Astronomy | Searching for the Inner Phase of Neutron Stars |
Oct 4 | TBD | ||
Oct 11 | Dr. Mircea Chipara | UTRGV, Physics and Astronomy | PHYSICAL ASPECTS IN POLYMER-BASED NANOCOMPOSITES |
Oct 25 | Dr. Ed Banigan | MIT, Physics, Institute for Medical Engineering and Science | |
Nov 1 | Canceled | ||
Nov 8 | Dr. Juan Madrid | UTRGV, Physics and Astronomy | |
Nov 15 | UTRGV Graduate Students | UTRGV, Physics and Astronomy |
Friday, February 1, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Noise reveals unusual pairs in cuprate superconductors
Superconductivity is the flow of electrical current with no resistance, thanks to the pairing up of charge carriers and their coherence in a single quantum state. In the 1980s, a family of copper oxide materials were discovered that show superconductivity at comparatively high temperatures, and after 30 years of study, we still don't have a good understanding of these compounds, including their properties in the "normal" state at temperatures above the superconducting transition, T c . Other effects are also seen (the "pseudogap"; spatial patterns of charge) in the normal and superconducting states. Two big questions have been, "Do the carriers actually pair up at even higher temperatures, and only start to superconduct at the transition?", and "What is the relationship between superconductivity and other kinds of electronic states?" Working with atomically precise materials, we have measured quantum tunneling of charge from one copper oxide superconductor to another, through a copper oxide insulating barrier. From the fluctuations in the tunneling current ("shot noise"), we have shown directly that there are pairs above T c , and that these pairs survive out to energy scales much larger than superconductivity. I will discuss what these measurements imply for the answer to those open questions.
Speaker: Dr. Douglas Natelson (Rice University, the Department of Physics and Astronomy)
Friday, February 8, 2019
Time: 12 pm - 1:30 pm
Location: EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Peakon, cuspon, and short pulse models generated through the negative-order integrable systems
In my talk, I will introduce integrable peakon and cuspon equations and present a basic approach to get peakon solutions. Those equations include the well-known Camassa-Holm (CH), the Degasperis-Procesi (DP), and other new peakon equations. I take the CH case as a typical example to explain the details. My presentation is based on my previous work (Communications in Mathematical Physics 239, 309-341). I will show that the Camassa-Holm (CH) spectral problem yields two different integrable hierarchies of nonlinear evolution equations (NLEEs), one is of negative order CH hierarchy while the other one is of positive order CH hierarchy. The two CH hierarchies possess the zero curvature representations through solving a key matrix equation. We see that the well-known CH equation is included in the negative order CH hierarchy while the Dym type equation is included in the positive order CH hierarchy. Also, in this talk, we will see those physical models: short pulse (SP), complex short pulse (CSP), two-component SP (2SP), and two-component CSP (2CSP) equations were derived from the negative AKNS flows (see JMP 44(2003), 701-722 for details), and Lax pair for those models and the entire hierarchy was explicitly provided as well. Some open problems are also addressed for discussion.
Speaker: Dr. Zhijun Qiao (UTRGV, Math)
Friday, February 15, 2019
Time: 12 pm - 1:30 pm
Location: EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Electron Density Topological Analysis and its applications on adsorption
The quantum theory of atoms in molecules (QTAIM), developed by Bader and co- workers, teaches that wavefunctions and orbitals are unphysical in nature and thus, not observed experimentally. However, the election density and its derivatives are observables (i.e., current density and election density Laplacian) and can be used to describe chemical bonding. Calculated QTAIM properties are method and basis-set independent. In QTAIM, the electron density contains all information needed to describe a chemical system. For example, nuclei locations correspond to electron density maxima, whereas bonds critical points to saddle points in the density. Additionally, the election density Laplacian provides a shell-type spherical structure in alternating shells of charge concentration and depletion: It is used to identify donor-acceptor interactions. We use QTAIM to analyze CO adsorption on hydrated and dry Pt surfaces and examine Li and Na adsorptions on graphene and graphene oxides. Specifically, the electron density Hessian eigenvalues are correlated with changes in the σ and π C-O bonding for various CO coverages and hydrations. The Li and Na adsorptions on graphene and graphene oxides (GO) electronic and structural properties are correlated with changes in the metal-C bond critical points for adsorption on various supports (i.e., pristine and defective graphene and GO) at various metal coverages. QTAIM reveals that Li forms a partially covalent bond with graphene carbon, when Li is adsorbed on single vacancy graphene. The above adsorptions are also analyzed using the changes in the electron localization function (ELF) via the development of bifurcation diagrams.
Speaker: Dr. Nicholas Dimakis (UTRGV, Physics)
Friday, February 22, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Detection of Gravitational Waves from Core Collapse Supernovae
Core collapse supernovae (CCSN) in our universe are potential sources of gravitational waves (GW) that could be detected in a network of GW detectors. CCSN rates are low, but the associated GW is likely to carry profuse information about the underlying processes leading to the collapse. Calculations based on analytic models predict GW energies within the detection range of the Advanced LIGO detectors, out to tens of Mpc for coalescing binary neutron stars. But for supernovae, the distances are much less. Improvements in the sensitivity of searches for GW signals from CCSN are highly desirable. Several methods have been proposed based on various likelihood-based regulators that work on data from a network of detectors We have developed an analysis pipeline based on a new way to effectively enhance the signal to noise ratio leading to a higher efficiency detection and increase of the detection range. Results using real LIGO noise and some of the current CCSN explosion models will be discussed.
Speaker: Dr. Soma Mukherjee (UTRGV, Physics and Astronomy)
Friday, March 1, 2019
Time: 12 pm - 1:30 pm
Location: EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Science and Technology of Graphene-family Nanomaterials: Opportunities at the Grand Challenges of Energy-Water-Sensing Nexus
Graphene, an atomic thin sheet of sp 2-hybridized carbon atoms joined covalently to form a two-dimensional (2D) hexagonal honeycomb lattice, has stimulated extensive research and development interests since its inception due to extraordinary physical-chemical-biological properties. Likewise, graphene-family nanomaterials (GFNs) including graphene oxide (GO), reduced GO (rGO), doped (nitrogen, boron and sulfur) graphene nanosheets and nano/macroporous graphene are equally emerging candidates for a range of technologies, especially at the grand challenges of renewable energy, water detoxification and sensing applications. In this talk, I will present ongoing research in my group related to graphene-based hybrids and aerogels and their widespread attention as potential game changer materials, accelerated by combining them with other nanomaterials such as transition metal oxides, conducting polymers, noble metal nanoparticles and carbon nanotubes. In the first part, I will discuss novel synthetic approaches for strategic material design targeting specific application, examples include: a) chemical and molecularly bridged graphene/metal oxides via electrodeposition; b) shear-aligned graphene oxide large-area membranes; and c) integrating carbon nanotubes as ‘nano’ spacers with graphene for increasing surface area for electrosorption and as ‘organic’ thermo-electrochemical energy harvesters [1-5]. For the second part of my talk, advanced characterization gaining fundamental insights into the mechanisms related to electrochemical energy storage, water desalination or sensing highlighting the interfacial properties will be presented [1-5]. The scanning electrochemical microscopy (SECM) is a powerful analytical tool to investigate dynamic physical-chemical processes occurring at surfaces and buried interfaces. This technique helps to determine heterogeneous electron transfer kinetic rate, diffusion coefficient, monitor electrochemical redox reactions as well as image highly electroactivity sites. These findings supplemented by theoretical calculations, reinforce the available electron density of states for the systems studied in the vicinity of the Fermi level contributing to higher electroactivity are emphasized [1-3, 6]. Finally, this research work opens up new innovations for graphene-based and graphene-related 2D systems as quantum materials with significant value propositions for academicians and industrials alike.[1] Gupta et al., Appl. Phys. Lett. 109, 243903 (2016).
[2] Gupta et al., J. Appl. Phys. 124, 124304 (2018)
[3] Gupta et al., J. Mater. Res. 32, 301 (2017).
[4] Gupta et al., Sensors & Actuators B 274, 85 (2018).
[5] Gupta et al., submitted (2019).
[6] Gupta et al., Appl. Surf. Sci. 465, 760 (2019).
Speaker: Dr. Sanju Gupta (Western Kentucky University, Physics and Astronomy, Advanced Materials Institute)
Friday, March 8, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
The future of the Universe:
Will we ever have a theory of everything?
In this colloquium I will discuss, at a non-technical level, several conundrums we face in our understanding of the universe. I will describe the crisis of the standard model of particle physics, the quandaries presented by the search for dark matter and the characterization of what we call dark energy. I will discuss how could they be related to finding a quantum theory of gravity. I will compare them with the various attempts through history to have a unified view of the physical phenomena in our universe. I will finally reflect on the possible solution to some of them from the optimistic perspective of a gravitational wave Astronomer.
Speaker: Dr. Mario Diaz (UTRGV, Physics and Astronomy, Center for Gravitation Wave Astronomy)
Friday, March 22, 2019
Time: 12 pm - 1:30 pm
Location: EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Single-molecule studies of how MORC protein functions and condenses DNA
Microrchidia (MORC) proteins are a highly conserved family of GHKL (Gyrase, HSP90, Histidine Kinase, MutL) ATPases that are critical for gene silencing and chromatin compaction in both plants and animals. However, the functional mechanism by which MORCs act is poorly understood. Here we show that C. elegans MORC-1 protein binds to DNA in a length-dependent yet non-sequence specific manner. To further elucidate mechanisms of MORC function, various single-molecule techniques were employed. First, our single-molecule flow-stretching experiments show that it can robustly compact naked DNA in a mildly ATP-dependent manner. After initial binding to DNA, MORC-1 forms multimeric assemblies that grow as DNA compaction proceeds, which is consistent with our observations that MORC-1 forms discrete nuclear puncta in C. elegans. Another single-molecule technique called DNA motion-capture assay based on the laminar flow nature of our microfluidic flowcell indicates that this DNA condensation activity appears to act via a loop trapping mechanism. Furthermore, the multimeric assemblies do not leave the flow-stretched DNA upon high salt wash when the free end of the DNA is tagged with a bulky quantum dot, which suggests that they topologically entrap the DNA. These results highlight several aspects of MORC-1 complex assembly on DNA that are relevant to understanding the fundamental mechanism of MORC action in a variety of organisms.
Speaker: Dr. HyeongJun Kim (UTRGV, Physics and Astronomy)
Friday, April 5, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.312 (Brownsville), EENGR 1.262 (Edinburg)
Mining Metastable Phase Space for New Function: Some Perspectives for the Design of Cathode Materials and Logic Circuitry
The known crystal structures of solids often correspond to the most thermodynamically stable arrangement of atoms. Yet, oftentimes there exist a richly diverse set of alternative structural arrangements that lie at only slightly higher energies and can be stabilized under specific constraints (temperature, pressure, alloying, point defects). Such metastable phase space holds opportunities for non-equilibrium structural motifs and distinctive chemical bonding and ultimately for the realization of novel function. I will discuss the challenges with the prediction, stabilization, and utilization of metastable polymorphs. Using two canonical early transition-metal oxides, HfO 2 and V 2O 5, as illustrative examples where emerging synthetic strategies have unveiled novel polymorphs, I will highlight the tunability of electronic structure, the potential richness of energy landscapes, and the implications for functional properties. In recent work, we have explored the intriguing electronic phase diagrams of low-dimensional ternary vanadium oxides with the formula M x V 2O 5 where M is an intercalating cation and x is its stoichiometry. Several of these compounds show colossal metal—insulator transitions and charge ordering phenomena. The talk will focus on mechanistic understanding of these transitions and their implications for the design of new “brain-like” vectors for computing. If composition does not have to be structural destiny, a powerful new palette becomes available for tuning material properties. I will demonstrate the application of this M x V 2O 5 palette to two specific problems: (a) the design of cathode materials for multivalent insertion batteries; and (b) the design of photocatalysts for the water oxidation reaction. Schematic illustration of the energy landscape of HfO 2
Speaker: Dr. Sarbajit Banerjee (Texas A&M University, College Station)
Friday, April 12, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EENGR 1.262 (Edinburg)
How to publish in Physical Review Letters
Publication is an essential part of scholarly research and integral to most scientists' careers. A good understanding of the authoring and reviewing processes helps authors navigate their way to a published manuscript. In this colloquium, editor from Physical Review Letters and will give an overview of the policies and procedures, and an update on publishing news from Physical Review journals.
Speaker: Dr. Stojan Rebic (Physical Review Letters, Associate Editor)
Friday, April 18, 2019
Time: 12 pm - 1:30 pm
Location: BSABH 2.110 (Brownsville), ELABS 185 (Edinburg)
News from the NSF
I will discuss the current status of the NSF and talk about various funding opportunities in Physics and Astronomy.
Speaker: Dr. Matthew Benacquista (UTRGV, Physics & Astronomy, NSF)
Friday, April 26, 2019
Time: 12 pm - 1:30 pm
Location:EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Harnessing the intermolecular Coulombic decay mechanism for targeted energy transfer in solution
Intermolecular Coulombic decay (ICD) is a well-established mechanism for energy transfer between core-excited atoms and their neighbors. Some years ago, my collaborators and I used plane-wave density functional theory (pwDFT) and a simple density-of-states (DOS) comparison to explain ICD-related features in the x-ray photoelectron spectrum of aqueous NaOH. Here I present extensions of this qualitative approach for predicting ICD that depend only on information easily obtained by molecular dynamics simulation and pwDFT. Specifically, we develop energetic criteria based on excess overlap between chemically distinct contributions to the total DOS, as well as complementary spatial criteria based on the radial distribution function. We use these measures to predict the preferred target for ICD from core-excited bismuth(III) in an aqueous solution containing citrate anions and 1,4-dioxane. Synchrotron experiments demonstrate not only that citrate is the target, as predicted, but that there is a fivefold enhancement in the citrate:dioxane destruction ratio over background radiolysis (i.e., in the absence of bismuth) that drops off as bismuth precipitates from the solution. I will discuss how our criteria can be used to screen for ICD propensity and how to estimate near-field effects in the corresponding measurements using analytic calculations of solid angles. Throughout, I will emphasize that these insights may contribute to the development of new coadjuvant therapies for use in cancer radiotherapy. Time allowing, I will summarize other current research and opportunities in my group for students in the Department of Physics and Astronomy.
Speaker: Dr. Shervin Fatehi (UTRGV, Chemistry)
Advanced LIGO’s third observing run has begun
Advanced LIGO’s third observing run has started on April 1 after a series of upgrades that increased its sensitivity by 40%. The talk will report on the improvements that went into the detectors and will show results and observations that have been made so far by previous observing runs.
Speaker: Dr. Volker Quetschke (UTRGV, Physics and Astronomy)
Size- and Shape- Controlled Properties of Nanostructured Systems
In the last decade there has been a significant progress in condensed matter physics at the nanoscopic level with development of several new concepts that provided variety applications on the size and shape dependent phenomena. This talk will summarize our current progress towards developing a framework of principles for design and fabrication of nano tailored structures to use in highly dense energetic systems, environmental protection and biomedical applications. I will present novel metastable intermolecular composites that enable a more concentrated energy release and potentially can be used in military, space and bio defeat applications. The novel patented cost-effective and energy efficient synthesis of nanostructured complex oxides and fabrication of various devices/systems such as hard and soft magnetic materials, superconductors, multiferroics, environmental photocatalysts, MRI contrast agents for cancer localization and hyperthermia treatment will be presented. Key factors that affected to the device characteristics (magnetization, conductivity, capacity, relaxation time, and others) will be discussed in details. Development of these emerging technologies warrants a multifaceted approach, which includes interdisciplinary collaboration, partnerships and integration of modern problems into materials physics curriculum.
Speaker: Dr. Karen Martirosyan (UTRGV, Physics and Astronomy)
Colloquium 2019
Date | Speaker | Institution | Title |
---|---|---|---|
Feb 1 | Dr. Douglas Natelson | Rice Univ. | Noise reveals unusual pairs in cuprate superconductors |
Feb 8 | Dr. Zhijun Qiao | UTRGV, Math | Peakon, cuspon, and short pulse models generated through the negative-order integrable systems |
Feb 15 | Dr. Nicholas Dimakis | UTRGV, Physics | Electron Density Topological Analysis and its applications on adsorption |
Feb 22 | Dr. Soma Mukherjee | UTRGV, Physics | Detection of Gravitational Waves from Core Collapse Supernovae |
Mar 1 | Dr. Sanju Gupta | Western Kentucky Univ. | Science and Technology of Graphene-family Nanomaterials: Opportunities at the Grand Challenges of Energy-Water-Sensing Nexus |
Mar 8 | Dr. Mario Diaz | UTRGV, Physics | The future of the Universe: Will we ever have a theory of everything? |
Mar 22 | Dr. Hyeongjun Kim | UTRGV, Physics | Single-molecule studies of how MORC protein functions and condenses DNA |
Apr 5 | Dr. Sarbajit Banerjee | Texas A&M Univ.-College Statoin | Mining Metastable Phase Space for New Function: Some Perspectives for the Design of Cathode Materials and Logic Circuitry |
Apr 12 | Dr. Stojan Rebic | PRL, Assoc. Editor | How to publish in Physical Review Letters |
Apr 18 | Dr. Matthew Benacquista | UTRGV, Physics, NSF | News from the NSF |
Apr 26 | Dr. Shervin Fatehi | UTRGV, Chemistry | Harnessing the intermolecular Coulombic decay mechanism for targeted energy transfer in solution |
Aug 30 |
Dr. Volker Quetschke | UTRGV, Physics and Astronomy | Advanced LIGO’s third observing run has begun |
Sept 6 | Dr. Karen Martirosyan | UTRGV, Physics and Astronomy | Size- and Shape- Controlled Properties of Nanostructured Systems |
Sept 13 | Dr. Soumya Mohanty | UTRGV, Physics and Astronomy | Swarm intelligence in Gravitational Wave data analysis |
Sept 27 | Dr. Efrain Ferrer | UTRGV, Physics and Astronomy | Searching for the Inner Phase of Neutron Stars |
Oct 4 | TBD | ||
Oct 11 | Dr. Mircea Chipara | UTRGV, Physics and Astronomy | PHYSICAL ASPECTS IN POLYMER-BASED NANOCOMPOSITES |
Oct 25 | Dr. Ed Banigan | MIT, Physics, Institute for Medical Engineering and Science | |
Nov 1 | Canceled | ||
Nov 8 | Dr. Juan Madrid | UTRGV, Physics and Astronomy | |
Nov 15 | UTRGV Graduate Students | UTRGV, Physics and Astronomy |
Friday, February 1, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Noise reveals unusual pairs in cuprate superconductors
Superconductivity is the flow of electrical current with no resistance, thanks to the pairing up of charge carriers and their coherence in a single quantum state. In the 1980s, a family of copper oxide materials were discovered that show superconductivity at comparatively high temperatures, and after 30 years of study, we still don't have a good understanding of these compounds, including their properties in the "normal" state at temperatures above the superconducting transition, T c . Other effects are also seen (the "pseudogap"; spatial patterns of charge) in the normal and superconducting states. Two big questions have been, "Do the carriers actually pair up at even higher temperatures, and only start to superconduct at the transition?", and "What is the relationship between superconductivity and other kinds of electronic states?" Working with atomically precise materials, we have measured quantum tunneling of charge from one copper oxide superconductor to another, through a copper oxide insulating barrier. From the fluctuations in the tunneling current ("shot noise"), we have shown directly that there are pairs above T c , and that these pairs survive out to energy scales much larger than superconductivity. I will discuss what these measurements imply for the answer to those open questions.
Speaker: Dr. Douglas Natelson (Rice University, the Department of Physics and Astronomy)
About the speaker: Prof. Natelson earned a BSE in Mech. and Aerospace Engineering at Princeton and a PhD in physics at Stanford, followed by a postdoctoral stint at Bell Labs before coming to Rice University in 2000. His research program uses nanoscale structures as tools to address open questions in condensed matter physics. Prof. Natelson is particularly interested in the electronic, optical, and magnetic properties of systems with strong electronic correlations and/or driven out of equilibrium, and always keeps one eye on possible technological applications. He is a fellow of the APS and AAAS, and is currently chair of Rice’s Department of Physics and Astronomy. Prof. Natelson is passionate about the importance of communicating science to the public, and has maintained a blog about nano and condensed matter (nanoscale.blogspot.com) since 2005 to further this goal. He has also written a senior-level textbook, Nanostructures and Nanotechnology, published in 2015 by Cambridge University Press (amazon.com/Nanostructures-Nanotechnology-Douglas-Natelson/dp/0521877008/).Friday, February 8, 2019
Time: 12 pm - 1:30 pm
Location: EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Peakon, cuspon, and short pulse models generated through the negative-order integrable systems
In my talk, I will introduce integrable peakon and cuspon equations and present a basic approach to get peakon solutions. Those equations include the well-known Camassa-Holm (CH), the Degasperis-Procesi (DP), and other new peakon equations. I take the CH case as a typical example to explain the details. My presentation is based on my previous work (Communications in Mathematical Physics 239, 309-341). I will show that the Camassa-Holm (CH) spectral problem yields two different integrable hierarchies of nonlinear evolution equations (NLEEs), one is of negative order CH hierarchy while the other one is of positive order CH hierarchy. The two CH hierarchies possess the zero curvature representations through solving a key matrix equation. We see that the well-known CH equation is included in the negative order CH hierarchy while the Dym type equation is included in the positive order CH hierarchy. Also, in this talk, we will see those physical models: short pulse (SP), complex short pulse (CSP), two-component SP (2SP), and two-component CSP (2CSP) equations were derived from the negative AKNS flows (see JMP 44(2003), 701-722 for details), and Lax pair for those models and the entire hierarchy was explicitly provided as well. Some open problems are also addressed for discussion.
Speaker: Dr. Zhijun Qiao (UTRGV, Math)
Friday, February 15, 2019
Time: 12 pm - 1:30 pm
Location: EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Electron Density Topological Analysis and its applications on adsorption
The quantum theory of atoms in molecules (QTAIM), developed by Bader and co- workers, teaches that wavefunctions and orbitals are unphysical in nature and thus, not observed experimentally. However, the election density and its derivatives are observables (i.e., current density and election density Laplacian) and can be used to describe chemical bonding. Calculated QTAIM properties are method and basis-set independent. In QTAIM, the electron density contains all information needed to describe a chemical system. For example, nuclei locations correspond to electron density maxima, whereas bonds critical points to saddle points in the density. Additionally, the election density Laplacian provides a shell-type spherical structure in alternating shells of charge concentration and depletion: It is used to identify donor-acceptor interactions. We use QTAIM to analyze CO adsorption on hydrated and dry Pt surfaces and examine Li and Na adsorptions on graphene and graphene oxides. Specifically, the electron density Hessian eigenvalues are correlated with changes in the σ and π C-O bonding for various CO coverages and hydrations. The Li and Na adsorptions on graphene and graphene oxides (GO) electronic and structural properties are correlated with changes in the metal-C bond critical points for adsorption on various supports (i.e., pristine and defective graphene and GO) at various metal coverages. QTAIM reveals that Li forms a partially covalent bond with graphene carbon, when Li is adsorbed on single vacancy graphene. The above adsorptions are also analyzed using the changes in the electron localization function (ELF) via the development of bifurcation diagrams.
Speaker: Dr. Nicholas Dimakis (UTRGV, Physics)
Friday, February 22, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Detection of Gravitational Waves from Core Collapse Supernovae
Core collapse supernovae (CCSN) in our universe are potential sources of gravitational waves (GW) that could be detected in a network of GW detectors. CCSN rates are low, but the associated GW is likely to carry profuse information about the underlying processes leading to the collapse. Calculations based on analytic models predict GW energies within the detection range of the Advanced LIGO detectors, out to tens of Mpc for coalescing binary neutron stars. But for supernovae, the distances are much less. Improvements in the sensitivity of searches for GW signals from CCSN are highly desirable. Several methods have been proposed based on various likelihood-based regulators that work on data from a network of detectors We have developed an analysis pipeline based on a new way to effectively enhance the signal to noise ratio leading to a higher efficiency detection and increase of the detection range. Results using real LIGO noise and some of the current CCSN explosion models will be discussed.
Speaker: Dr. Soma Mukherjee (UTRGV, Physics and Astronomy)
Friday, March 1, 2019
Time: 12 pm - 1:30 pm
Location: EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Science and Technology of Graphene-family Nanomaterials: Opportunities at the Grand Challenges of Energy-Water-Sensing Nexus
Graphene, an atomic thin sheet of sp 2-hybridized carbon atoms joined covalently to form a two-dimensional (2D) hexagonal honeycomb lattice, has stimulated extensive research and development interests since its inception due to extraordinary physical-chemical-biological properties. Likewise, graphene-family nanomaterials (GFNs) including graphene oxide (GO), reduced GO (rGO), doped (nitrogen, boron and sulfur) graphene nanosheets and nano/macroporous graphene are equally emerging candidates for a range of technologies, especially at the grand challenges of renewable energy, water detoxification and sensing applications. In this talk, I will present ongoing research in my group related to graphene-based hybrids and aerogels and their widespread attention as potential game changer materials, accelerated by combining them with other nanomaterials such as transition metal oxides, conducting polymers, noble metal nanoparticles and carbon nanotubes. In the first part, I will discuss novel synthetic approaches for strategic material design targeting specific application, examples include: a) chemical and molecularly bridged graphene/metal oxides via electrodeposition; b) shear-aligned graphene oxide large-area membranes; and c) integrating carbon nanotubes as ‘nano’ spacers with graphene for increasing surface area for electrosorption and as ‘organic’ thermo-electrochemical energy harvesters [1-5]. For the second part of my talk, advanced characterization gaining fundamental insights into the mechanisms related to electrochemical energy storage, water desalination or sensing highlighting the interfacial properties will be presented [1-5]. The scanning electrochemical microscopy (SECM) is a powerful analytical tool to investigate dynamic physical-chemical processes occurring at surfaces and buried interfaces. This technique helps to determine heterogeneous electron transfer kinetic rate, diffusion coefficient, monitor electrochemical redox reactions as well as image highly electroactivity sites. These findings supplemented by theoretical calculations, reinforce the available electron density of states for the systems studied in the vicinity of the Fermi level contributing to higher electroactivity are emphasized [1-3, 6]. Finally, this research work opens up new innovations for graphene-based and graphene-related 2D systems as quantum materials with significant value propositions for academicians and industrials alike.[1] Gupta et al., Appl. Phys. Lett. 109, 243903 (2016).[2] Gupta et al., J. Appl. Phys. 124, 124304 (2018)
[3] Gupta et al., J. Mater. Res. 32, 301 (2017).
[4] Gupta et al., Sensors & Actuators B 274, 85 (2018).
[5] Gupta et al., submitted (2019).
[6] Gupta et al., Appl. Surf. Sci. 465, 760 (2019).
Speaker: Dr. Sanju Gupta (Western Kentucky University, Physics and Astronomy, Advanced Materials Institute)
Friday, March 8, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
The future of the Universe:
Will we ever have a theory of everything?
In this colloquium I will discuss, at a non-technical level, several conundrums we face in our understanding of the universe. I will describe the crisis of the standard model of particle physics, the quandaries presented by the search for dark matter and the characterization of what we call dark energy. I will discuss how could they be related to finding a quantum theory of gravity. I will compare them with the various attempts through history to have a unified view of the physical phenomena in our universe. I will finally reflect on the possible solution to some of them from the optimistic perspective of a gravitational wave Astronomer.
Speaker: Dr. Mario Diaz (UTRGV, Physics and Astronomy, Center for Gravitation Wave Astronomy)
Friday, March 22, 2019
Time: 12 pm - 1:30 pm
Location: EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Single-molecule studies of how MORC protein functions and condenses DNA
Microrchidia (MORC) proteins are a highly conserved family of GHKL (Gyrase, HSP90, Histidine Kinase, MutL) ATPases that are critical for gene silencing and chromatin compaction in both plants and animals. However, the functional mechanism by which MORCs act is poorly understood. Here we show that C. elegans MORC-1 protein binds to DNA in a length-dependent yet non-sequence specific manner. To further elucidate mechanisms of MORC function, various single-molecule techniques were employed. First, our single-molecule flow-stretching experiments show that it can robustly compact naked DNA in a mildly ATP-dependent manner. After initial binding to DNA, MORC-1 forms multimeric assemblies that grow as DNA compaction proceeds, which is consistent with our observations that MORC-1 forms discrete nuclear puncta in C. elegans. Another single-molecule technique called DNA motion-capture assay based on the laminar flow nature of our microfluidic flowcell indicates that this DNA condensation activity appears to act via a loop trapping mechanism. Furthermore, the multimeric assemblies do not leave the flow-stretched DNA upon high salt wash when the free end of the DNA is tagged with a bulky quantum dot, which suggests that they topologically entrap the DNA. These results highlight several aspects of MORC-1 complex assembly on DNA that are relevant to understanding the fundamental mechanism of MORC action in a variety of organisms.Speaker: Dr. HyeongJun Kim (UTRGV, Physics and Astronomy)
Friday, April 5, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.312 (Brownsville), EENGR 1.262 (Edinburg)
Mining Metastable Phase Space for New Function: Some Perspectives for the Design of Cathode Materials and Logic Circuitry
The known crystal structures of solids often correspond to the most thermodynamically stable arrangement of atoms. Yet, oftentimes there exist a richly diverse set of alternative structural arrangements that lie at only slightly higher energies and can be stabilized under specific constraints (temperature, pressure, alloying, point defects). Such metastable phase space holds opportunities for non-equilibrium structural motifs and distinctive chemical bonding and ultimately for the realization of novel function. I will discuss the challenges with the prediction, stabilization, and utilization of metastable polymorphs. Using two canonical early transition-metal oxides, HfO 2 and V 2O 5, as illustrative examples where emerging synthetic strategies have unveiled novel polymorphs, I will highlight the tunability of electronic structure, the potential richness of energy landscapes, and the implications for functional properties. In recent work, we have explored the intriguing electronic phase diagrams of low-dimensional ternary vanadium oxides with the formula M x V 2O 5 where M is an intercalating cation and x is its stoichiometry. Several of these compounds show colossal metal—insulator transitions and charge ordering phenomena. The talk will focus on mechanistic understanding of these transitions and their implications for the design of new “brain-like” vectors for computing. If composition does not have to be structural destiny, a powerful new palette becomes available for tuning material properties. I will demonstrate the application of this M x V 2O 5 palette to two specific problems: (a) the design of cathode materials for multivalent insertion batteries; and (b) the design of photocatalysts for the water oxidation reaction.
Speaker: Dr. Sarbajit Banerjee (Texas A&M University, College Station)
Friday, April 12, 2019
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EENGR 1.262 (Edinburg)
How to publish in Physical Review Letters
Publication is an essential part of scholarly research and integral to most scientists' careers. A good understanding of the authoring and reviewing processes helps authors navigate their way to a published manuscript. In this colloquium, editor from Physical Review Letters and will give an overview of the policies and procedures, and an update on publishing news from Physical Review journals.Speaker: Dr. Stojan Rebic (Physical Review Letters, Associate Editor)
Friday, April 18, 2019
Time: 12 pm - 1:30 pm
Location: BSABH 2.110 (Brownsville), ELABS 185 (Edinburg)
News from the NSF
I will discuss the current status of the NSF and talk about various funding opportunities in Physics and Astronomy.Speaker: Dr. Matthew Benacquista (UTRGV, Physics & Astronomy, NSF)
Friday, April 26, 2019
Time: 12 pm - 1:30 pm
Location:EACSB 1.104 (Edinburg), BLHSB 1.104 (Brownsville)
Harnessing the intermolecular Coulombic decay mechanism for targeted energy transfer in solution
Intermolecular Coulombic decay (ICD) is a well-established mechanism for energy transfer between core-excited atoms and their neighbors. Some years ago, my collaborators and I used plane-wave density functional theory (pwDFT) and a simple density-of-states (DOS) comparison to explain ICD-related features in the x-ray photoelectron spectrum of aqueous NaOH. Here I present extensions of this qualitative approach for predicting ICD that depend only on information easily obtained by molecular dynamics simulation and pwDFT. Specifically, we develop energetic criteria based on excess overlap between chemically distinct contributions to the total DOS, as well as complementary spatial criteria based on the radial distribution function. We use these measures to predict the preferred target for ICD from core-excited bismuth(III) in an aqueous solution containing citrate anions and 1,4-dioxane. Synchrotron experiments demonstrate not only that citrate is the target, as predicted, but that there is a fivefold enhancement in the citrate:dioxane destruction ratio over background radiolysis (i.e., in the absence of bismuth) that drops off as bismuth precipitates from the solution. I will discuss how our criteria can be used to screen for ICD propensity and how to estimate near-field effects in the corresponding measurements using analytic calculations of solid angles. Throughout, I will emphasize that these insights may contribute to the development of new coadjuvant therapies for use in cancer radiotherapy. Time allowing, I will summarize other current research and opportunities in my group for students in the Department of Physics and Astronomy.Speaker: Dr. Shervin Fatehi (UTRGV, Chemistry)
About the speaker: Shervin Fatehi earned an S.B. in chemistry from MIT in 2004. He spent a year studying the statistical mechanics of liquids with David Chandler at UC Berkeley before changing focus to approximate quantum dynamics methods and theoretical X-ray spectroscopy, completing a Ph.D under the supervision of William H. Miller and Richard J. Saykally in 2010. During consecutive postdoctoral appointments (2011–2015) with Joseph E. Subotnik (University of Pennsylvania) and Ryan P. Steele (University of Utah), he developed expertise in nonadia- batic phenomena, analytic gradient theory, and ab initio molecular dynamics. In Fall 2015, Dr. Fatehi joined the founding faculty of UTRGV as a member of the Department of Chemistry. His current research focuses on the development of theoretical and computational methods that deepen our understanding of the interplay between the electronic structure of molecules (quantum chemistry), their motions and rearrangements (chemical dynamics), and their inter- actions with light (spectroscopy). Projects include exploring the importance of nonadiabatic effects in mechanochemistry and the application of stochastic electronic structure methods to simulating molecular motion; the latter work is funded by the Welch Foundation.
Advanced LIGO’s third observing run has begun
Advanced LIGO’s third observing run has started on April 1 after a series of upgrades that increased its sensitivity by 40%. The talk will report on the improvements that went into the detectors and will show results and observations that have been made so far by previous observing runs.
Speaker: Dr. Volker Quetschke (UTRGV, Physics and Astronomy)
About the speaker: Dr. Volker Quetschke is an Associate Professor in Department of Physics and Astronomy at UTRGV. He joined UTB/UTRGV in 2009 and while he maintains a strong research agenda in experimental gravitational wave detector physics, he has been extremely active in service and leadership activities. He shows great dedication to help the profession, the department, the college, and the university in general. He believes improving the university makes it a better place for students and faculty while student success and research are strengthened. He earned his doctoral degree in 2003 at the Leibniz University in Hannover, Germany working on identifying and reducing the noise of laser systems for gravitational wave detectors. He joined the University of Florida in 2003 and became first a post-doctoral researcher and later a Research Assistant Professor. Dr. Quetschke’s research mainly focusses on the Laser Interferometer Gravitational-Wave Observatory (LIGO) where he is involved in improving the laser and input optics as well as designing the next generation detector. He chairs the Lasers and Auxiliary Optics working group of the LIGO Scientific Collaboration (LSC) and is a council member of the LSC. The LSC consists of more than 1000 scientists from over 100 institutions and 18 countries worldwide. Dr. Quetschke holds two patents and has published more than 200 peer reviewed articles.
His scholarly activities already reflect his involvement in service and leadership for the academy, but in addition to that he serves as the Associate Chair of the Department of Physics & Astronomy at UTRGV and in several committees. Dr. Quetschke leads the Arecibo Remote Command Center (ARCC) of the Center for Advanced Radio Astronomy (CARA). ARCC is a unique program that provides a cohort-based education to undergraduate students, while exposing them early to research projects. He is representing the interests of the faculty as a member of the Faculty Senate at UTRGV and currently serves as the President of the Senate. Statewide he is representing the faculty as Co-chair for Academic Affairs and Faculty Quality of the University of Texas System Faculty Advisory Council (FAC).
Dr. Quetschke is a co-recipient of the Breakthrough Prize 2016 for detection of Gravitational Waves 100 Years after Albert Einstein predicted their existence and a co-recipient of the 2016 Gruber Cosmology Prize for pursuing a vision to observe the universe in gravitational waves, leading to a first detection that emanated from the collision of two black holes.
Size- and Shape- Controlled Properties of Nanostructured Systems
In the last decade there has been a significant progress in condensed matter physics at the nanoscopic level with development of several new concepts that provided variety applications on the size and shape dependent phenomena. This talk will summarize our current progress towards developing a framework of principles for design and fabrication of nano tailored structures to use in highly dense energetic systems, environmental protection and biomedical applications. I will present novel metastable intermolecular composites that enable a more concentrated energy release and potentially can be used in military, space and bio defeat applications. The novel patented cost-effective and energy efficient synthesis of nanostructured complex oxides and fabrication of various devices/systems such as hard and soft magnetic materials, superconductors, multiferroics, environmental photocatalysts, MRI contrast agents for cancer localization and hyperthermia treatment will be presented. Key factors that affected to the device characteristics (magnetization, conductivity, capacity, relaxation time, and others) will be discussed in details. Development of these emerging technologies warrants a multifaceted approach, which includes interdisciplinary collaboration, partnerships and integration of modern problems into materials physics curriculum.
Speaker: Dr. Karen Martirosyan (UTRGV, Physics and Astronomy)
About the speaker: Dr. Martirosyan’s research interests are focusing on the design and fabrication of a novel advanced multifunctional nano-tailored devices and systems for energy, environmental and biomedical applications. The research area covers a broad spectrum of advanced materials, their design, fabrication, characterization and solid-state phenomena. He has been the principal investigator and co-investigator for numerous Federal and State funded research projects. His work has resulted in more than 130+ refereed journal papers, 20 patents and over 150 presentations at national and international conferences. He was three-time recipient of the AFRL summer fellowship program at Eglin Air Force Base, Florida.
Swarm intelligence in Gravitational Wave data analysis
As in many other fields of science dominated by Big Data problems, the success of gravitational wave Astronomy depends critically on solving outstanding and difficult data analysis challenges. Many of these challenges are rooted in the difficulty of numerically optimizing functions that are high-dimensional and multi-modal. At UTRGV, we have pioneered the use of cutting-edge stochastic optimization methods from the field of swarm intelligence to address some of these problems. In this talk, we will review the work that has been done in this area at UTRGV and the successes we have had. These successes in turn point the way to new and interesting data analysis challenges, not limited to gravitational wave data analysis alone, that are ripe for solution using swarm intelligence methods.
Speaker: Dr. Soumya Mohanty (UTRGV, Physics and Astronomy)
TOROS, the present and the future
A project status report
In this talk I review the status of the TOROS project, which seeks to install, commission and operate a wide field of view optical telescope in the highlands of the Atacama dessert.
The main goal of the project is to follow-up and characterize gravitational wave transients in the electromagnetic spectrum. I will also discuss the current LIGO VIRGO observational campaign, its provisional preliminary results and the prospects for the new ones after 2020.
Speaker: Dr. Mario Diaz (UTRGV, Physics and Astronomy)
Searching for the Inner Phase of Neutron Stars
Compact stars with significant high densities in their interiors can give rise to quark deconfined phases that can open a window for the study of strongly interacting dense nuclear matter. Recent observations on the mass of two pulsars, PSR J1614-2230 and PSR J0348+0432, have posed a great restriction on their composition, since their equations of state must be hard enough to support masses of about at least two solar masses. On the other hand, from spectroscopic and spin-down studies of soft-γ-ray repeaters (SGRs) and anomalous x-ray pulsars (AXPs), it has been inferred that surface magnetic fields of order 10 14−10 15G occur in some special compact objects called magnetars. Moreover, the inner core magnetic fields of magnetars can be even larger, as follows from the magnetic field flux conservation in stellar media with very large electric conductivities. The inner fields have been estimated to range from 10 18G for nuclear-matter stars to 10 20G for quark-matter stars.
The onset of quarks tends to soften the equation of state, but due to their strong interactions, different phases can be realized with new parameters that affect the corresponding equations of state and ultimately the mass-radius relationships. In this talk I will review how the equation of state of dense quark matter is affected by the physical characteristics of the phases that can take place at different baryonic densities, as well as in the presence of strong magnetic fields.
Speaker: Dr. Efrain J. Ferrer (UTRGV, Physics and Astronomy)
PHYSICAL ASPECTS IN POLYMER-BASED NANOCOMPOSITES
The seminar will focus on one of my most important research directions in nanomaterials, namely the physical properties of polymer-based nanocomposites. Polymer-based nanocomposites is a class of materials that typically involves polymeric matrices loaded by various nanoparticles. Frequently this definition is extended to include polymer blend, when the physical features of at least one component is controlled by submicron confinement or interfaces as well as classical composite materials, with a micron filler or larger if the surface is very thin (usually below 100 nm) and some physical properties are controlled by the interface.
The nanofiller adds new physical properties to the polymer-based nanocomposites such as electrical conductivity, magnetic characteristics, dielectric features. The huge possibilities to modify the physical properties of the polymeric matrix by adding such nanoparticles open the door to new materials, with advanced properties, and eventually multifunctional properties. The methods to obtain such nanocomposites are typically easy scaled up to industrial scale, explaining thus the huge interest of the industry.
My research in the last years was concentrated on the following directions:
- The polymer-nanofiller interface and the transition from the bulk to the surface properties in polymer-based nanocomposites.
- Phase transitions (glass, melting, and crystallization) and molecular dynamics in polymer based nanocomposites
- Polymer nanofibers and their nanocomposites
- Molecular basis of the elasticity of polymeric materials and polymer-based nanocomposites, as revealed by vibrational spectroscopy (Raman and FTIR).
The colloquium will briefly discuss all these directions, while focusing on recent data in the study of the molecular basis of elasticity in polymer-based nanocomposites by Raman spectroscopy.
Speaker: Dr. Mircea Chipara (UTRGV, Physics and Astronomy)
Friday, October 25, 2019
Physical mechanisms of cell nuclear mechanics and structure
The cell nucleus is often referred to as the control center of the cell because it houses the genome, which encodes cellular function. However, the nucleus is also a mechanically responsive object that actively organizes and physically protects the >1-meter-long chromatin polymer (DNA and proteins) contained within. To understand the physical mechanisms of these phenomena, I use simulation and theory to explore: 1) how two major nuclear components govern mechanical response and 2) how mesoscale chromosome folding is driven by molecular motors. First, I show that chromatin has an essential role in maintaining nuclear structure. Nuclear mechanical response is well described by a model of a chromatin polymer gel enclosed by a polymeric lamin shell. This model predicts an experimentally observable, strain-stiffening mechanical response. These mechanics lead to a buckling transition and regulate nuclear shape abnormalities found in human diseases, such as progeria and breast cancer. Second, I develop a theory for “loop-extruding” condensin protein complexes, which linearly compact chromosomes 1000-fold by reeling in DNA and extruding it as loops. While a form of this novel motor activity has been observed in recent in vitro single-molecule experiments, my theory predicts that the microscopic observations cannot fully explain in vivo human chromosome compaction. However, the model suggests how condensins may nonetheless achieve such dramatic compaction in vivo. Together, the models and corresponding experiments demonstrate how biologically essential cell-nuclear properties emerge from the mechanical response and nonequilibrium activities of chromatin.
Speaker: Dr. Edward J. Banigan (MIT, Physics, Institute for Medical Engineering and Science)
Friday, November 8, 2019
Globular clusters
Globular star clusters are densely packed spherical agglomerations of stars. These stellar systems are found orbiting our own galaxy, the Milky Way and all kinds of galaxies across the Universe. Globular clusters feature prominently in different aspects of astrophysical research, for example they provide an accurate measurement of the age of the Universe. Globular clusters are also used to trace the dynamical evolution of galaxies, and galaxy clusters. The internal dynamics of globular clusters can be studied with N-body simulations. These dynamical simulations tell us how the hundreds of thousands of stars that form a globular cluster interact with one another. As one of the densest stellar structures in the Universe stellar collisions are known to frequently occur within globular clusters, among them the binary systems that are responsible for gravitational waves.
Speaker: Dr. Juan Madrid (UTRGV, Physics and Astronomy)
Friday, November 15, 2019
(Talk 1) Optical Configurations of Laser Gravitational Wave Detectors
Speaker: Mr. Anton Gribovskiy (UTRGV, Physics and Astronomy, 6 th year PhD student)
(Talk 2) Improving Models of Thermal Atmospheric Newtonian Noise for Advanced and 3 rd Generation Gravitational-Wave Detectors
Speaker: Ms. Wenhui Wang (UTRGV, Physics and Astronomy, 5 th year PhD student)
Date
|
Speaker
|
Institution
|
Title
|
Jan 19
|
Xiaorui Zheng
|
The City Univ. of New York
|
Scanning Probe Nano-Lithography with SwissLitho's NanoFrazor
|
Jan 26
|
Taft Armandroff
|
McDonald Observatory & UT Austin
|
Progress and Prospects at the McDonald Observatory
|
Feb 2
|
Muhammad Bhatti
|
UTRGV
|
Cancer Treatment Using High Frequency Electromagnetic Waves
|
Feb 9
|
Matthew Shetrone
|
McDonald Observatory & UT Austin
|
Constraints on Milky Way halo formation using the most metal-rich halo stars
|
Feb 16
|
Diana Berman
|
University of North Texas
|
The Origin of Macroscale Superlubricity in Carbon Nanomaterials
|
Feb 23
|
Qian Niu
|
UT Austin
|
Geometrodynamics of Bloch electrons
|
Mar 2
|
Choongbae Park
|
Texas A&M Univ.-Kingsville
|
Micron-resolution Particle Image Velocimetry (µPIV) Analysis of Microfluidic Applications: Hydrodynamically Confined Flows and Opto-electrokinetic Flows
|
Mar 9
|
Kevin Stovall
|
Univ. of New Mexico, National Astronomy Observatory
|
PALFA Discovery of a Highly Relativistic Double Neutron Star Binary
|
Mar 23
|
Peter Armitage
|
Johns Hopkins University
|
On Ising's model of ferromagnetism
|
Apr 20
|
Mark Williams
|
Northeastern University
|
Single molecule DNA-protein interactions: Battling retroviruses and controlling genome access
|
Sep 7
|
Myoung-Hwan Kim
|
UTRGV
|
Finding Nano-blocks to control light
|
Sep 14
|
Ahmed Touhami
|
UTRGV
|
Biofilms and mechanics: Forces in Microbial Community
|
Sep 21
|
Weihong Qiu
|
Oregon State Univ
|
Kinesin-14s: Moving into a New Paradigm
|
Sep 28
|
Yuanbing Mao
|
UTRGV, Chemistry
|
Correlating the Synthesis-Structure-Property Relationship of Complex Metal Oxide Nanomaterials
|
Oct 5
|
Hyun-Chul Lee
|
UTRGV
|
Understanding of Galaxies Using the Four Corner Stellar Populations in the Color - Magnitude Diagram
|
Oct 12
|
Baofeng Feng
|
UTRGV, Math
|
Mathematical models and computations for ultrashort laser pulse propagation
|
Oct 19
|
Jun Yan
|
UMass Amherst
|
Multi-particle bound states in a two-dimensional semiconductor
|
Oct 26
|
Luis Grave De Peralta
|
Texas Tech Univ
|
Scanning Diffracted-Light (SDL) Imaging
|
Nov 9
|
Mohammad R. K. Mofrad
|
UC Berkeley
|
Physics of Signal Transduction in Living Cells: Conformational Switch, Activation and Clustering
|
Nov 16
|
Qing Gu
|
UT Dallas
|
From Nanoscale Emitters to Photonic Integrated Circuits
|
Nov 30
|
Marc Normandin
|
UTRGV
|
Data analysis methods for gravitational wave searches from binary inspirals and gamma-ray bursts
|
Friday, January 19, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Scanning Probe Nano-Lithography with SwissLitho’s NanoFrazor
Progress in nanotechnology depends on the capability to fabricate, position and interconnect nanometer-scale structures. However, existing conventional lithography techniques pose limitations and challenges related to resolution, operational costs, and more importantly, the lack of flexibility to pattern novel materials such as graphene and transition-metal dichalcogenides. Since the first patterning experiments performed with a scanning probe microscope in the late 1980s, scanning probe lithography has emerged as an alternative type of lithography for academic research that provides striking capabilities to pattern three-dimensional relief structures with nanoscale features; the fabrication of the smallest field-effect transistor; or the patterning of proteins with 10-nm feature size. In this presentation, I will introduce the innovative NanoFrazor, the first commercialized scanning probe lithography platform, and focus on its great potential in the emerging research on two-dimensional materials.
Speaker: Dr. Xiaorui Zheng (The City University of New York and SwissLitho)
Friday, January 26, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Progress and Prospects at the McDonald Observatory
Taft Armandroff has served as Director of the McDonald Observatory since June 2014. His talk will include recent progress at McDonald Observatory on new instruments, telescope and instrument upgrades, and plans for the future. A number of enhancements are underway or complete, including a wide-field upgrade and powerful new instrument suite for the Hobby-Eberly 10-meter Telescope. The University of Texas at Austin (UT Austin) is a significant partner in the Giant Magellan Telescope (GMT) in Chile, which will be the world’s largest optical / infrared telescope when it begins commissioning in 2023. GMT plans and prospects and will be reviewed. UT Austin is developing instrumentation for GMT.
Speaker: Dr. Taft Armandroff (McDonald Observatory and UT Austin)
Friday, February 2, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Cancer Treatment Using High Frequency Electromagnetic Waves
The primary objective of this research endeavor is to study and to understand the natural physics phenomenon of electromagnetic resonance in one end closed cavity for the eventual purpose of cancer treatment. Radio Frequency waves are discharged into a coaxial cavity with a small amount (1.532 mL) of breast cancer cells (BT549) and the reflection as well as the power input is measured to determine the absorption power into the vitro cancer cell experiment. When the reflection of the RF waves from the loaded sample of cancer cells is at its lowest power, the RF Frequency is noted and seen to be approximately close to the resonant frequency of that cavity. This cavity can potentially be used as a control method of testing RF frequencies on various types of cancer cells, such as the available BT549 cancer cell line from Biology department. The determined frequency for 1.532 mL of sample article is found to be in the range of radio frequency, but there is much room for improvement depending on the coaxial cavity design such as length and the radii of the coaxial tubes which are under investigation. Some preliminary results are obtained which show that the electromagnetic waves induce cancer cell death via a process known as apoptosis. The results of the experiment will be presented in the colloquium talk.
Speaker: Dr. Muhammad Bhatti (UTRGV)
Friday, February 9, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Constraints on Milky Way halo formation using the most metal-rich halo stars
The Milky Way halo is halo contains mostly very old stars but may still be in the process of construction via cannibalism. While most surveys have concentrated on the most metal-poor stars in the halo we have taken the opposite tactic by looking at the most metal-rich (relatively) stars. Using 6-10 meter class telescopes such as the Magellan, VLT and HET we have constructed a sample of faint, outer halo, metal-rich, in-situ stars for which we have obtained chemical abundance ratios. These abundance ratios reveal their star formation history. Using the SDSS-IV APOGEE survey and combing those results with the early GAIA results we can construct a second set of metal-rich stars in the inner or local halo. We leverage the power of the APOGEE survey by contrasting the abundances of these halo stars against those found in the Milky Way thick disk and bulge. By looking at the results for the metal-rich inner and outer halo stars we speculate on the possible growth mechanisms for the Milky Way halo.
Speaker: Dr. Matthew Shetrone (McDonald Observatory & UT Austin)
Friday, February 16, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
The Origin of Macroscale Superlubricity in Carbon Nanomaterials.
Tribological systems are an integral part of any moving mechanical assembly, from nanoscale microelectromechanical systems to macroscale automotive and aerospace applications. Minimizing friction and wear-related mechanical failures in order to allow superior performance and long-lasting operation of moving mechanical systems remains the one of today’s greatest challenges. Despite intense research efforts superlubricity, or near zero friction, has seldom been achieved at engineering scales or in practical systems. Much of the difficulty has often been due to the very complex physical, chemical, and mechanical interactions that occur simultaneously at sliding interfaces of mechanical systems. In this study we evaluate tribological performance of carbon nanomaterials [1-2], and demonstrate realization of superlubricity regime at macroscale in an all-carbon-based ensemble when diamond nanoparticles are mixed with graphene and slide against diamond-like carbon (DLC) surface [3]. We show that during sliding in dry atmosphere, graphene patches wrap around tiny diamond nanoparticles and form nanoscrolls, thus dramatically reducing the contact area with a perfectly incommensurate DLC surface. The coefficient of friction reaches ultralow values (0.004) thus demonstrating the long-lasting superlubric regime. This superlubricity is stable over range of temperature, load, and sliding velocity conditions. Our large-scale molecular dynamic simulations elucidate the mesoscopic link between nanoscale mechanics and macroscopic experimental observations. The highlighted carbon-based superlubricity provides a fundamental basis for developing universal friction mechanism and offers a direct pathway for designing smart frictionless tribological systems for practical applications of industrial interest.
References:
[1] D. Berman, et al., special issue in Diamond and Related Materials, 54, 91 (2015).
[2] D. Berman, et al., Materials Today 17 (2014) 31-42.
[3] D. Berman, et al., Science, 348 (2015) 1118-1122
Speaker:
Dr. Diana Berman (University of North Texas)
Friday, February 23, 2018
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Geometrodynamics of Bloch electrons
Semiclassical dynamics of Bloch electrons in a crystal under slowly varying deformation is developed in the geometric language of a lattice bundle. Berry curvatures and gradients of energy are introduced in terms of lattice covariant derivatives, with the corresponding connections given by the gradient and rate of strain. A number of physical effects are discussed: an effective post-Newtonian gravity at band bottom, polarization induced by spatial gradient of strain, orbital magnetization induced by strain rate, and electron energy stress tensor.
Speaker: Dr. Qian Niu (The University of Texas at Austin)
Colloquium 2018
Date | Speaker | Institution | Title |
Jan 19 | Xiaorui Zheng | The City Univ. of New York | Scanning Probe Nano-Lithography with SwissLitho's NanoFrazor |
Jan 26 | Taft Armandroff | McDonald Observatory & UT Austin | Progress and Prospects at the McDonald Observatory |
Feb 2 | Muhammad Bhatti | UTRGV | Cancer Treatment Using High Frequency Electromagnetic Waves |
Feb 9 | Matthew Shetrone | McDonald Observatory & UT Austin | Constraints on Milky Way halo formation using the most metal-rich halo stars |
Feb 16 | Diana Berman | University of North Texas | The Origin of Macroscale Superlubricity in Carbon Nanomaterials |
Feb 23 | Qian Niu | UT Austin | Geometrodynamics of Bloch electrons |
Mar 2 | Choongbae Park | Texas A&M Univ.-Kingsville | Micron-resolution Particle Image Velocimetry (µPIV) Analysis of Microfluidic Applications: Hydrodynamically Confined Flows and Opto-electrokinetic Flows |
Mar 9 | Kevin Stovall | Univ. of New Mexico, National Astronomy Observatory | PALFA Discovery of a Highly Relativistic Double Neutron Star Binary |
Mar 23 | Peter Armitage | Johns Hopkins University | On Ising's model of ferromagnetism |
Apr 20 | Mark Williams | Northeastern University | Single molecule DNA-protein interactions: Battling retroviruses and controlling genome access |
Sep 7 | Myoung-Hwan Kim | UTRGV | Finding Nano-blocks to control light |
Sep 14 | Ahmed Touhami | UTRGV | Biofilms and mechanics: Forces in Microbial Community |
Sep 21 | Weihong Qiu | Oregon State Univ | Kinesin-14s: Moving into a New Paradigm |
Sep 28 | Yuanbing Mao | UTRGV, Chemistry | Correlating the Synthesis-Structure-Property Relationship of Complex Metal Oxide Nanomaterials |
Oct 5 | Hyun-Chul Lee | UTRGV | Understanding of Galaxies Using the Four Corner Stellar Populations in the Color - Magnitude Diagram |
Oct 12 | Baofeng Feng | UTRGV, Math | Mathematical models and computations for ultrashort laser pulse propagation |
Oct 19 | Jun Yan | UMass Amherst | Multi-particle bound states in a two-dimensional semiconductor |
Oct 26 | Luis Grave De Peralta | Texas Tech Univ | Scanning Diffracted-Light (SDL) Imaging |
Nov 9 | Mohammad R. K. Mofrad | UC Berkeley | Physics of Signal Transduction in Living Cells: Conformational Switch, Activation and Clustering |
Nov 16 | Qing Gu | UT Dallas | From Nanoscale Emitters to Photonic Integrated Circuits |
Nov 30 | Marc Normandin | UTRGV | Data analysis methods for gravitational wave searches from binary inspirals and gamma-ray bursts |
Friday, January 19, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Scanning Probe Nano-Lithography with SwissLitho’s NanoFrazor
Progress in nanotechnology depends on the capability to fabricate, position and interconnect nanometer-scale structures. However, existing conventional lithography techniques pose limitations and challenges related to resolution, operational costs, and more importantly, the lack of flexibility to pattern novel materials such as graphene and transition-metal dichalcogenides. Since the first patterning experiments performed with a scanning probe microscope in the late 1980s, scanning probe lithography has emerged as an alternative type of lithography for academic research that provides striking capabilities to pattern three-dimensional relief structures with nanoscale features; the fabrication of the smallest field-effect transistor; or the patterning of proteins with 10-nm feature size. In this presentation, I will introduce the innovative NanoFrazor, the first commercialized scanning probe lithography platform, and focus on its great potential in the emerging research on two-dimensional materials.
Speaker: Dr. Xiaorui Zheng (The City University of New York and SwissLitho)
About the speaker: Dr. Xiaorui Zheng was awarded the degree of PhD at Swinburne University of Technology (Australia) for his thesis entitled “The optics and applications of graphene oxide.” Prior to his appointment as SwissLitho Postdoc Fellow, Xiaorui worked as a research fellow at University of California, San Diego. Xiaorui’s current research interests lie in the nano-photonics of low-dimensional materials for both functional photonic and bio-medical applications using the NanoFrazor.
Friday, January 26, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Progress and Prospects at the McDonald Observatory
Taft Armandroff has served as Director of the McDonald Observatory since June 2014. His talk will include recent progress at McDonald Observatory on new instruments, telescope and instrument upgrades, and plans for the future. A number of enhancements are underway or complete, including a wide-field upgrade and powerful new instrument suite for the Hobby-Eberly 10-meter Telescope. The University of Texas at Austin (UT Austin) is a significant partner in the Giant Magellan Telescope (GMT) in Chile, which will be the world’s largest optical / infrared telescope when it begins commissioning in 2023. GMT plans and prospects and will be reviewed. UT Austin is developing instrumentation for GMT.
Speaker: Dr. Taft Armandroff (McDonald Observatory and UT Austin)
Friday, February 2, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Cancer Treatment Using High Frequency Electromagnetic Waves
The primary objective of this research endeavor is to study and to understand the natural physics phenomenon of electromagnetic resonance in one end closed cavity for the eventual purpose of cancer treatment. Radio Frequency waves are discharged into a coaxial cavity with a small amount (1.532 mL) of breast cancer cells (BT549) and the reflection as well as the power input is measured to determine the absorption power into the vitro cancer cell experiment. When the reflection of the RF waves from the loaded sample of cancer cells is at its lowest power, the RF Frequency is noted and seen to be approximately close to the resonant frequency of that cavity. This cavity can potentially be used as a control method of testing RF frequencies on various types of cancer cells, such as the available BT549 cancer cell line from Biology department. The determined frequency for 1.532 mL of sample article is found to be in the range of radio frequency, but there is much room for improvement depending on the coaxial cavity design such as length and the radii of the coaxial tubes which are under investigation. Some preliminary results are obtained which show that the electromagnetic waves induce cancer cell death via a process known as apoptosis. The results of the experiment will be presented in the colloquium talk.
Speaker: Dr. Muhammad Bhatti (UTRGV)
Friday, February 9, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Constraints on Milky Way halo formation using the most metal-rich halo stars
The Milky Way halo is halo contains mostly very old stars but may still be in the process of construction via cannibalism. While most surveys have concentrated on the most metal-poor stars in the halo we have taken the opposite tactic by looking at the most metal-rich (relatively) stars. Using 6-10 meter class telescopes such as the Magellan, VLT and HET we have constructed a sample of faint, outer halo, metal-rich, in-situ stars for which we have obtained chemical abundance ratios. These abundance ratios reveal their star formation history. Using the SDSS-IV APOGEE survey and combing those results with the early GAIA results we can construct a second set of metal-rich stars in the inner or local halo. We leverage the power of the APOGEE survey by contrasting the abundances of these halo stars against those found in the Milky Way thick disk and bulge. By looking at the results for the metal-rich inner and outer halo stars we speculate on the possible growth mechanisms for the Milky Way halo.
Speaker: Dr. Matthew Shetrone (McDonald Observatory & UT Austin)
About the speaker:
Undergraduate degree: University of Texas at Austin 1991
Graduate degree: University of California, Santa Cruz 1996
Post-doc: ESO fellow (Chile) 1996-1997
Resident Astronomer and Senior Research Scientist for Hobby-Eberly Telescope 1998-2018
Current Service Duties: Science Operations Manager, Deputy Facility Manager
Current Research Duties: APOGEE architect, HET Parallel Scientist
Friday, February 16, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
The Origin of Macroscale Superlubricity in Carbon Nanomaterials.
Tribological systems are an integral part of any moving mechanical assembly, from nanoscale microelectromechanical systems to macroscale automotive and aerospace applications. Minimizing friction and wear-related mechanical failures in order to allow superior performance and long-lasting operation of moving mechanical systems remains the one of today’s greatest challenges. Despite intense research efforts superlubricity, or near zero friction, has seldom been achieved at engineering scales or in practical systems. Much of the difficulty has often been due to the very complex physical, chemical, and mechanical interactions that occur simultaneously at sliding interfaces of mechanical systems. In this study we evaluate tribological performance of carbon nanomaterials [1-2], and demonstrate realization of superlubricity regime at macroscale in an all-carbon-based ensemble when diamond nanoparticles are mixed with graphene and slide against diamond-like carbon (DLC) surface [3]. We show that during sliding in dry atmosphere, graphene patches wrap around tiny diamond nanoparticles and form nanoscrolls, thus dramatically reducing the contact area with a perfectly incommensurate DLC surface. The coefficient of friction reaches ultralow values (0.004) thus demonstrating the long-lasting superlubric regime. This superlubricity is stable over range of temperature, load, and sliding velocity conditions. Our large-scale molecular dynamic simulations elucidate the mesoscopic link between nanoscale mechanics and macroscopic experimental observations. The highlighted carbon-based superlubricity provides a fundamental basis for developing universal friction mechanism and offers a direct pathway for designing smart frictionless tribological systems for practical applications of industrial interest.
References:
[1] D. Berman, et al., special issue in Diamond and Related Materials, 54, 91 (2015).
[2] D. Berman, et al., Materials Today 17 (2014) 31-42.
[3] D. Berman, et al., Science, 348 (2015) 1118-1122
Speaker:
Dr. Diana Berman (University of North Texas)
Dr. Diana Berman is currently an Assistant Professor in the Department of Materials Science and Engineering at University of North Texas. Dr. Berman received her BS in Applied Physics and Math from Moscow Institute of Physics and Technology and PhD in Physics from North Carolina State University. During her PhD she was working on the first generation of RF MEMS switches and the adhesion and wear associated failures in them. Since 2012 she worked as a PostDoctoral researcher and then as a Research Associate in the Center for Nanoscale Materials at Argonne National Laboratory on understanding the fundamental mechanisms of superlubricity, the vanishing friction and wear regime. Dr. Berman’s research interests are in synthesis and characterization of nanostructures, surfaces, and interfaces of ceramic and carbon-based materials for precise control and improvement of their physical properties and performance. Dr. Berman is specifically interested in tribological performance of materials, such as nanoscale contact evolution, interaction of material with environment, and macroscale friction and wear of sliding systems. Dr. Berman has published several high-impact-factor papers with over 1000 citations (in journals Science, Nature Communications, Advanced Functional Materials, ACS Nano, etc) and given several plenary and invited talks and presentations (2017 APS/CNM Annual Meeting, 2016 Gordon Research Conference in Tribology, 2015 Argonne Tribology Workshop). Her work was recognized with TechConnect National Innovation Awards at 2016 and 2017 TechConnect's annual World Innovation Conferences and Expo. Dr. Berman has been an organizer and chair of several Conferences and Workshops (1 st Tribology Workshop and Poster Presentation of STLE North Texas Chapter, STLE Annual Meetings 2016-2017, NDNC 2014, 2015 APS/CNM User Meeting Workshop, 2014 Argonne PostDoctoral Symposium).
Friday, February 23, 2018
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Geometrodynamics of Bloch electrons
Semiclassical dynamics of Bloch electrons in a crystal under slowly varying deformation is developed in the geometric language of a lattice bundle. Berry curvatures and gradients of energy are introduced in terms of lattice covariant derivatives, with the corresponding connections given by the gradient and rate of strain. A number of physical effects are discussed: an effective post-Newtonian gravity at band bottom, polarization induced by spatial gradient of strain, orbital magnetization induced by strain rate, and electron energy stress tensor.
Speaker: Dr. Qian Niu (The University of Texas at Austin)
Friday, March 2, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Micron-resolution Particle Image Velocimetry (μPIV) Analysis of Microfluidic Applications: Hydro-dynamically Confined Flows and Optoelectrokinetic Flows
Two microfluidic applications have been analyzed experimentally using micron-resolution particle image velocimetry (μPIV). The first application is microfluidic probe (MFP) that can be used to generate hydrodynamically confined microflows (HCMs) in open liquid environments. The MFP is immersed in a liquid reservoir and a flow is generated beneath the device. This allows for the application of microfluidic approaches to many biological applications that are typically performed in dishes and well plates. The direct measurement of in-plane velocity fields in the flow beneath an MFP will be presented. Secondly, the combination of AC electric fields and optical illumination allows for the easy and rapid creation of microvortex flows inside a microchannel for applications such as micropumping and micromixing. The manipulation and flow characterization of opto-electrokinetically generated microflows called twin opposing microvortex (TOMV) flows will be presented. This technique has the advantage of simpler construction than competing techniques. The measurement of the microvortex flows generated under non-uniform electric fields and a highly focused laser beam due to a unique characteristics of the TOMV flows will be presented.
Speaker: Dr. Choongbae Park (Texas A&M University - Kingsville)
Friday, March 9, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
PALFA Discovery of a Highly Relativistic Double Neutron Star Binary
In August 2017, the PALFA survey discovered a pulsar (PSR J1946+2052) with a 17 ms spin period in a 1.88 hour, eccentric (e~0.06) orbit with a ~1.2 solar mass companion. Soon after discovery, we used the Jansky Very Large Array to localize PSR J1946+2052 to a precision of 0.09 arcseconds using a new phase binning mode. This improved position allowed for us to measure a spin period derivative which indicates the pulsar has a weak magnetic field compared to "normal" pulsars and therefore has been recycled through mass transfer from a companion. This combined with the orbital eccentricity lead to the conclusion that PSR J1946+2052 is in a DNS system. Among all known radio pulsars in DNS systems, PSR J1946+2052 has the shortest orbital period and the shortest estimated merger timescale, 46 Myr; at that time it will display the largest spin effects on gravitational-wave waveforms of any such system discovered to date. In this talk, I will describe the PALFA survey, the discovery of J1946+2052, and discuss what is currently known about the system. I will also discuss the future plans for this pulsar system including other relativistic orbital parameters that we expect to be able to detect in the coming years.
Speaker: Dr. Kevin Stovall (The Univ. of New Mexico, National Radio Astronomy Observatory, Socorro)
Friday, March 23, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
On Ising's model of ferromagnetism
The 1D Ising model is a classical model of great historical significance for both classical and quantum statistical mechanics. Developments in the understanding of the Ising model have fundamentally impacted our knowledge of thermodynamics, critical phenomena, magnetism, conformal quantum field theories, particle physics, and emergence in many-body systems. Despite the theoretical impact of the Ising model there have been very few good 1D realizations of it in actual real material systems. However, it has been pointed out recently, that the material CoNb2O6, has a number of features that may make it the most ideal realization we have of the Ising model in one dimension. In this talk I will discuss the surprisingly complex physics resulting in this simple model and review the history of "Ising’s model” from both a scientific and human perspective. In the modern context I will review recent experiments by my group and others on CoNb2O6. In particular I will show how low frequency light in the THz range gives unique insight into the tremendous zoo of phenomena arising in this simple material system.
Speaker: Dr. Peter Armitage (Johns Hopkins University)
Colloquium 2018
Date | Speaker | Institution | Title |
Jan 19 | Xiaorui Zheng | The City Univ. of New York | Scanning Probe Nano-Lithography with SwissLitho's NanoFrazor |
Jan 26 | Taft Armandroff | McDonald Observatory & UT Austin | Progress and Prospects at the McDonald Observatory |
Feb 2 | Muhammad Bhatti | UTRGV | Cancer Treatment Using High Frequency Electromagnetic Waves |
Feb 9 | Matthew Shetrone | McDonald Observatory & UT Austin | Constraints on Milky Way halo formation using the most metal-rich halo stars |
Feb 16 | Diana Berman | University of North Texas | The Origin of Macroscale Superlubricity in Carbon Nanomaterials |
Feb 23 | Qian Niu | UT Austin | Geometrodynamics of Bloch electrons |
Mar 2 | Choongbae Park | Texas A&M Univ.-Kingsville | Micron-resolution Particle Image Velocimetry (µPIV) Analysis of Microfluidic Applications: Hydrodynamically Confined Flows and Opto-electrokinetic Flows |
Mar 9 | Kevin Stovall | Univ. of New Mexico, National Astronomy Observatory | PALFA Discovery of a Highly Relativistic Double Neutron Star Binary |
Mar 23 | Peter Armitage | Johns Hopkins University | On Ising's model of ferromagnetism |
Apr 20 | Mark Williams | Northeastern University | Single molecule DNA-protein interactions: Battling retroviruses and controlling genome access |
Sep 7 | Myoung-Hwan Kim | UTRGV | Finding Nano-blocks to control light |
Sep 14 | Ahmed Touhami | UTRGV | Biofilms and mechanics: Forces in Microbial Community |
Sep 21 | Weihong Qiu | Oregon State Univ | Kinesin-14s: Moving into a New Paradigm |
Sep 28 | Yuanbing Mao | UTRGV, Chemistry | Correlating the Synthesis-Structure-Property Relationship of Complex Metal Oxide Nanomaterials |
Oct 5 | Hyun-Chul Lee | UTRGV | Understanding of Galaxies Using the Four Corner Stellar Populations in the Color - Magnitude Diagram |
Oct 12 | Baofeng Feng | UTRGV, Math | Mathematical models and computations for ultrashort laser pulse propagation |
Oct 19 | Jun Yan | UMass Amherst | Multi-particle bound states in a two-dimensional semiconductor |
Oct 26 | Luis Grave De Peralta | Texas Tech Univ | Scanning Diffracted-Light (SDL) Imaging |
Nov 9 | Mohammad R. K. Mofrad | UC Berkeley | Physics of Signal Transduction in Living Cells: Conformational Switch, Activation and Clustering |
Nov 16 | Qing Gu | UT Dallas | From Nanoscale Emitters to Photonic Integrated Circuits |
Nov 30 | Marc Normandin | UTRGV | Data analysis methods for gravitational wave searches from binary inspirals and gamma-ray bursts |
Friday, January 19, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Scanning Probe Nano-Lithography with SwissLitho’s NanoFrazor
Progress in nanotechnology depends on the capability to fabricate, position and interconnect nanometer-scale structures. However, existing conventional lithography techniques pose limitations and challenges related to resolution, operational costs, and more importantly, the lack of flexibility to pattern novel materials such as graphene and transition-metal dichalcogenides. Since the first patterning experiments performed with a scanning probe microscope in the late 1980s, scanning probe lithography has emerged as an alternative type of lithography for academic research that provides striking capabilities to pattern three-dimensional relief structures with nanoscale features; the fabrication of the smallest field-effect transistor; or the patterning of proteins with 10-nm feature size. In this presentation, I will introduce the innovative NanoFrazor, the first commercialized scanning probe lithography platform, and focus on its great potential in the emerging research on two-dimensional materials.
Speaker: Dr. Xiaorui Zheng (The City University of New York and SwissLitho)
About the speaker: Dr. Xiaorui Zheng was awarded the degree of PhD at Swinburne University of Technology (Australia) for his thesis entitled “The optics and applications of graphene oxide.” Prior to his appointment as SwissLitho Postdoc Fellow, Xiaorui worked as a research fellow at University of California, San Diego. Xiaorui’s current research interests lie in the nano-photonics of low-dimensional materials for both functional photonic and bio-medical applications using the NanoFrazor.
Friday, January 26, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Progress and Prospects at the McDonald Observatory
Taft Armandroff has served as Director of the McDonald Observatory since June 2014. His talk will include recent progress at McDonald Observatory on new instruments, telescope and instrument upgrades, and plans for the future. A number of enhancements are underway or complete, including a wide-field upgrade and powerful new instrument suite for the Hobby-Eberly 10-meter Telescope. The University of Texas at Austin (UT Austin) is a significant partner in the Giant Magellan Telescope (GMT) in Chile, which will be the world’s largest optical / infrared telescope when it begins commissioning in 2023. GMT plans and prospects and will be reviewed. UT Austin is developing instrumentation for GMT.
Speaker: Dr. Taft Armandroff (McDonald Observatory and UT Austin)
Friday, February 2, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Cancer Treatment Using High Frequency Electromagnetic Waves
The primary objective of this research endeavor is to study and to understand the natural physics phenomenon of electromagnetic resonance in one end closed cavity for the eventual purpose of cancer treatment. Radio Frequency waves are discharged into a coaxial cavity with a small amount (1.532 mL) of breast cancer cells (BT549) and the reflection as well as the power input is measured to determine the absorption power into the vitro cancer cell experiment. When the reflection of the RF waves from the loaded sample of cancer cells is at its lowest power, the RF Frequency is noted and seen to be approximately close to the resonant frequency of that cavity. This cavity can potentially be used as a control method of testing RF frequencies on various types of cancer cells, such as the available BT549 cancer cell line from Biology department. The determined frequency for 1.532 mL of sample article is found to be in the range of radio frequency, but there is much room for improvement depending on the coaxial cavity design such as length and the radii of the coaxial tubes which are under investigation. Some preliminary results are obtained which show that the electromagnetic waves induce cancer cell death via a process known as apoptosis. The results of the experiment will be presented in the colloquium talk.
Speaker: Dr. Muhammad Bhatti (UTRGV)
Friday, February 9, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Constraints on Milky Way halo formation using the most metal-rich halo stars
The Milky Way halo is halo contains mostly very old stars but may still be in the process of construction via cannibalism. While most surveys have concentrated on the most metal-poor stars in the halo we have taken the opposite tactic by looking at the most metal-rich (relatively) stars. Using 6-10 meter class telescopes such as the Magellan, VLT and HET we have constructed a sample of faint, outer halo, metal-rich, in-situ stars for which we have obtained chemical abundance ratios. These abundance ratios reveal their star formation history. Using the SDSS-IV APOGEE survey and combing those results with the early GAIA results we can construct a second set of metal-rich stars in the inner or local halo. We leverage the power of the APOGEE survey by contrasting the abundances of these halo stars against those found in the Milky Way thick disk and bulge. By looking at the results for the metal-rich inner and outer halo stars we speculate on the possible growth mechanisms for the Milky Way halo.
Speaker: Dr. Matthew Shetrone (McDonald Observatory & UT Austin)
About the speaker:
Undergraduate degree: University of Texas at Austin 1991
Graduate degree: University of California, Santa Cruz 1996
Post-doc: ESO fellow (Chile) 1996-1997
Resident Astronomer and Senior Research Scientist for Hobby-Eberly Telescope 1998-2018
Current Service Duties: Science Operations Manager, Deputy Facility Manager
Current Research Duties: APOGEE architect, HET Parallel Scientist
Friday, February 16, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
The Origin of Macroscale Superlubricity in Carbon Nanomaterials.
Tribological systems are an integral part of any moving mechanical assembly, from nanoscale microelectromechanical systems to macroscale automotive and aerospace applications. Minimizing friction and wear-related mechanical failures in order to allow superior performance and long-lasting operation of moving mechanical systems remains the one of today’s greatest challenges. Despite intense research efforts superlubricity, or near zero friction, has seldom been achieved at engineering scales or in practical systems. Much of the difficulty has often been due to the very complex physical, chemical, and mechanical interactions that occur simultaneously at sliding interfaces of mechanical systems. In this study we evaluate tribological performance of carbon nanomaterials [1-2], and demonstrate realization of superlubricity regime at macroscale in an all-carbon-based ensemble when diamond nanoparticles are mixed with graphene and slide against diamond-like carbon (DLC) surface [3]. We show that during sliding in dry atmosphere, graphene patches wrap around tiny diamond nanoparticles and form nanoscrolls, thus dramatically reducing the contact area with a perfectly incommensurate DLC surface. The coefficient of friction reaches ultralow values (0.004) thus demonstrating the long-lasting superlubric regime. This superlubricity is stable over range of temperature, load, and sliding velocity conditions. Our large-scale molecular dynamic simulations elucidate the mesoscopic link between nanoscale mechanics and macroscopic experimental observations. The highlighted carbon-based superlubricity provides a fundamental basis for developing universal friction mechanism and offers a direct pathway for designing smart frictionless tribological systems for practical applications of industrial interest.
References:
[1] D. Berman, et al., special issue in Diamond and Related Materials, 54, 91 (2015).
[2] D. Berman, et al., Materials Today 17 (2014) 31-42.
[3] D. Berman, et al., Science, 348 (2015) 1118-1122
Speaker:
Dr. Diana Berman (University of North Texas)
Dr. Diana Berman is currently an Assistant Professor in the Department of Materials Science and Engineering at University of North Texas. Dr. Berman received her BS in Applied Physics and Math from Moscow Institute of Physics and Technology and PhD in Physics from North Carolina State University. During her PhD she was working on the first generation of RF MEMS switches and the adhesion and wear associated failures in them. Since 2012 she worked as a PostDoctoral researcher and then as a Research Associate in the Center for Nanoscale Materials at Argonne National Laboratory on understanding the fundamental mechanisms of superlubricity, the vanishing friction and wear regime. Dr. Berman’s research interests are in synthesis and characterization of nanostructures, surfaces, and interfaces of ceramic and carbon-based materials for precise control and improvement of their physical properties and performance. Dr. Berman is specifically interested in tribological performance of materials, such as nanoscale contact evolution, interaction of material with environment, and macroscale friction and wear of sliding systems. Dr. Berman has published several high-impact-factor papers with over 1000 citations (in journals Science, Nature Communications, Advanced Functional Materials, ACS Nano, etc) and given several plenary and invited talks and presentations (2017 APS/CNM Annual Meeting, 2016 Gordon Research Conference in Tribology, 2015 Argonne Tribology Workshop). Her work was recognized with TechConnect National Innovation Awards at 2016 and 2017 TechConnect's annual World Innovation Conferences and Expo. Dr. Berman has been an organizer and chair of several Conferences and Workshops (1 st Tribology Workshop and Poster Presentation of STLE North Texas Chapter, STLE Annual Meetings 2016-2017, NDNC 2014, 2015 APS/CNM User Meeting Workshop, 2014 Argonne PostDoctoral Symposium).
Friday, February 23, 2018
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Geometrodynamics of Bloch electrons
Semiclassical dynamics of Bloch electrons in a crystal under slowly varying deformation is developed in the geometric language of a lattice bundle. Berry curvatures and gradients of energy are introduced in terms of lattice covariant derivatives, with the corresponding connections given by the gradient and rate of strain. A number of physical effects are discussed: an effective post-Newtonian gravity at band bottom, polarization induced by spatial gradient of strain, orbital magnetization induced by strain rate, and electron energy stress tensor.
Speaker: Dr. Qian Niu (The University of Texas at Austin)
Friday, March 2, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Micron-resolution Particle Image Velocimetry (μPIV) Analysis of Microfluidic Applications: Hydro-dynamically Confined Flows and Optoelectrokinetic Flows
Two microfluidic applications have been analyzed experimentally using micron-resolution particle image velocimetry (μPIV). The first application is microfluidic probe (MFP) that can be used to generate hydrodynamically confined microflows (HCMs) in open liquid environments. The MFP is immersed in a liquid reservoir and a flow is generated beneath the device. This allows for the application of microfluidic approaches to many biological applications that are typically performed in dishes and well plates. The direct measurement of in-plane velocity fields in the flow beneath an MFP will be presented. Secondly, the combination of AC electric fields and optical illumination allows for the easy and rapid creation of microvortex flows inside a microchannel for applications such as micropumping and micromixing. The manipulation and flow characterization of opto-electrokinetically generated microflows called twin opposing microvortex (TOMV) flows will be presented. This technique has the advantage of simpler construction than competing techniques. The measurement of the microvortex flows generated under non-uniform electric fields and a highly focused laser beam due to a unique characteristics of the TOMV flows will be presented.
Speaker: Dr. Choongbae Park (Texas A&M University - Kingsville)
Friday, March 9, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
PALFA Discovery of a Highly Relativistic Double Neutron Star Binary
In August 2017, the PALFA survey discovered a pulsar (PSR J1946+2052) with a 17 ms spin period in a 1.88 hour, eccentric (e~0.06) orbit with a ~1.2 solar mass companion. Soon after discovery, we used the Jansky Very Large Array to localize PSR J1946+2052 to a precision of 0.09 arcseconds using a new phase binning mode. This improved position allowed for us to measure a spin period derivative which indicates the pulsar has a weak magnetic field compared to "normal" pulsars and therefore has been recycled through mass transfer from a companion. This combined with the orbital eccentricity lead to the conclusion that PSR J1946+2052 is in a DNS system. Among all known radio pulsars in DNS systems, PSR J1946+2052 has the shortest orbital period and the shortest estimated merger timescale, 46 Myr; at that time it will display the largest spin effects on gravitational-wave waveforms of any such system discovered to date. In this talk, I will describe the PALFA survey, the discovery of J1946+2052, and discuss what is currently known about the system. I will also discuss the future plans for this pulsar system including other relativistic orbital parameters that we expect to be able to detect in the coming years.
Speaker: Dr. Kevin Stovall (The Univ. of New Mexico, National Radio Astronomy Observatory, Socorro)
Friday, March 23, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
On Ising's model of ferromagnetism
The 1D Ising model is a classical model of great historical significance for both classical and quantum statistical mechanics. Developments in the understanding of the Ising model have fundamentally impacted our knowledge of thermodynamics, critical phenomena, magnetism, conformal quantum field theories, particle physics, and emergence in many-body systems. Despite the theoretical impact of the Ising model there have been very few good 1D realizations of it in actual real material systems. However, it has been pointed out recently, that the material CoNb2O6, has a number of features that may make it the most ideal realization we have of the Ising model in one dimension. In this talk I will discuss the surprisingly complex physics resulting in this simple model and review the history of "Ising’s model” from both a scientific and human perspective. In the modern context I will review recent experiments by my group and others on CoNb2O6. In particular I will show how low frequency light in the THz range gives unique insight into the tremendous zoo of phenomena arising in this simple material system.
Speaker: Dr. Peter Armitage (Johns Hopkins University)
Friday, April 20, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Single molecule DNA-protein interactions: Battling retroviruses and controlling genome access
Optical tweezers allow us to probe the interactions of proteins with single DNA molecules and apply very small forces. Measurement of force-dependent DNA conformations allows us to quantify interactions that govern cellular function. Here we investigate the DNA interactions of human APOBEC3G, an innate antiviral immunity protein that functions as a cytidine deaminase. Our results show that the process of interconversion between monomeric and dimeric states regulates APOBEC3G’s deamination-dependent and deamination-independent inhibition of HIV-1 replication. I will then discuss the role of eukaryotic HMGB proteins in determining nucleosome accessibility, an important mechanism for regulating protein expression. We construct an array of nucleosomes on a single DNA molecule, measuring nucleosome stability in the presence of HMGB proteins. We find significant unwrapping of nucleosomes due to HMBG-DNA binding, the extent of which differs between different types of HMGB proteins. The extent of observed destabilization correlates with the presence of nucleosome-free regions in cells, revealing distinct functions for regulation of nucleosome accessibility by different HMGB proteins.
Speaker: Dr. Mark C. Williams (Northeastern University)
Friday, September 7, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Finding Nano-blocks to Control Light
Metasurfaces have emerged in recent years as a platform for designing subwavelength-thick optical components. Such designer optical interfaces introduce spatially-varying optical responses which can mold the wavefronts of light. The reduced dimensionality of optical metasurfaces opens new physics and leads to novel functionalities distinctly different from those in three-dimensional optical materials. In this talk I will introduce the basic concept of metasurfaces to control light propagation in free space and in optical waveguides. Furthermore, I will present our recent experimental demonstration of a new metasurface platform with hyperbolic materials to control light localized on the surface. These metasurfaces can be the main building blocks in mid-/far infrared flat optics and integrated nanophotonics.
Speaker: Dr. Myoung-Hwan Kim (UTRGV)
Friday, September 14, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Biofilms and Mechanics: Forces in Microbial Community
Speaker: Dr. Ahmed Touhami (UTRGV)
Friday, September 21, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Kinesin-14s: Moving into a New Paradigm
Kinesin-14s are microtubule-based motor proteins that play important roles in cell division. They were originally thought to be minus-end-directed nonprocessive motors that exhibit directional preference toward the microtubule minus ends in multi-motor ensembles but are unable to generate processive (continuous) motility on single microtubules as individual motors. During the past five years, we and others have discovered several “unconventional” kinesin-14 motors that all contain the ability to generate processive motility as individual motors on single microtubules. In this talk, I will present a series of unexpected yet exciting findings from my lab that have markedly expanded current view of the design and operation principles of kinesin-14 motors.
Speaker: Dr. Weihong Qiu (Oregon State University)
Friday, September 28, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Correlating the Synthesis-Structure-Property Relationship of Complex Metal Oxide Nanomaterials
Understanding the synthesis-structure-property relationship of functional materials has paramount importance in order to meet the materials needs and challenges of our evolving and expanding society. Complex metal oxides and their nanomaterials have attracted intensive attention due to their chemical composition and structural flexibility, more importantly, their fascinating properties and broad application potentials. In this colloquium, after a brief overview, two types of functional metal oxides will be discussed to exemplify our recent research effort within this context. As an example of advanced (photo)electrochemical materials, it is expected that delafossites with CuIMIIIO2 composition could serve as potential candidates for cost-effective and active electrode material based on cyclic voltammetry and electrochemical impedance spectroscopy measurements along with their onset potential, current density, Tafel slope, charge transfer resistance, and stability. For luminescent materials useful for solid-state lighting, X-ray scintillators, and bioimaging, focus will be placed on our recent studies on the controllable synthesis of A2M2O7 nanoparticles, and investigation of the morphology and composition influence on their photoluminescence and radioluminescence. We have achieved substantial tunability of their particle size, crystal phase, and more importantly, optical properties. In sum, advanced electrochemical and optical materials of complex metal oxides offer bright promise of producing innovative advances across multiple technologies, and thus will continue impacting our lives in substantial ways.
Speaker: Dr. Yuanbing Mao (UTRGV, Chemistry)
Friday, October 5, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Understanding of Galaxies Using the Four Corner Stellar Populations in the Color – Magnitude Diagram
The Four Corner Stellar Populations in the Color – Magnitude Diagram that I will present in the talk are the blue horizontal-branch stars on the upper left, the tip of the red giant branch stars and the thermally pulsing asymptotic giant branch stars on the upper right, the main-sequence knee feature on the lower right, and the white dwarf cooling sequence on the lower left. The blue horizontal-branch stars, the main-sequence knee feature, and the white dwarf cooling sequence play important roles for the age estimation of star clusters and the tip of the red giant branch stars and the thermally pulsing asymptotic giant branch stars are of importance for the distance measurement of galaxies. I will conclude with the plan for the CSI Galaxies (Center for Stellar populations In Galaxies) at the UTRGV.
Speaker: Dr. Hyun-chul Lee (UTRGV)
Colloquium 2018
Date | Speaker | Institution | Title |
Jan 19 | Xiaorui Zheng | The City Univ. of New York | Scanning Probe Nano-Lithography with SwissLitho's NanoFrazor |
Jan 26 | Taft Armandroff | McDonald Observatory & UT Austin | Progress and Prospects at the McDonald Observatory |
Feb 2 | Muhammad Bhatti | UTRGV | Cancer Treatment Using High Frequency Electromagnetic Waves |
Feb 9 | Matthew Shetrone | McDonald Observatory & UT Austin | Constraints on Milky Way halo formation using the most metal-rich halo stars |
Feb 16 | Diana Berman | University of North Texas | The Origin of Macroscale Superlubricity in Carbon Nanomaterials |
Feb 23 | Qian Niu | UT Austin | Geometrodynamics of Bloch electrons |
Mar 2 | Choongbae Park | Texas A&M Univ.-Kingsville | Micron-resolution Particle Image Velocimetry (µPIV) Analysis of Microfluidic Applications: Hydrodynamically Confined Flows and Opto-electrokinetic Flows |
Mar 9 | Kevin Stovall | Univ. of New Mexico, National Astronomy Observatory | PALFA Discovery of a Highly Relativistic Double Neutron Star Binary |
Mar 23 | Peter Armitage | Johns Hopkins University | On Ising's model of ferromagnetism |
Apr 20 | Mark Williams | Northeastern University | Single molecule DNA-protein interactions: Battling retroviruses and controlling genome access |
Sep 7 | Myoung-Hwan Kim | UTRGV | Finding Nano-blocks to control light |
Sep 14 | Ahmed Touhami | UTRGV | Biofilms and mechanics: Forces in Microbial Community |
Sep 21 | Weihong Qiu | Oregon State Univ | Kinesin-14s: Moving into a New Paradigm |
Sep 28 | Yuanbing Mao | UTRGV, Chemistry | Correlating the Synthesis-Structure-Property Relationship of Complex Metal Oxide Nanomaterials |
Oct 5 | Hyun-Chul Lee | UTRGV | Understanding of Galaxies Using the Four Corner Stellar Populations in the Color - Magnitude Diagram |
Oct 12 | Baofeng Feng | UTRGV, Math | Mathematical models and computations for ultrashort laser pulse propagation |
Oct 19 | Jun Yan | UMass Amherst | Multi-particle bound states in a two-dimensional semiconductor |
Oct 26 | Luis Grave De Peralta | Texas Tech Univ | Scanning Diffracted-Light (SDL) Imaging |
Nov 9 | Mohammad R. K. Mofrad | UC Berkeley | Physics of Signal Transduction in Living Cells: Conformational Switch, Activation and Clustering |
Nov 16 | Qing Gu | UT Dallas | From Nanoscale Emitters to Photonic Integrated Circuits |
Nov 30 | Marc Normandin | UTRGV | Data analysis methods for gravitational wave searches from binary inspirals and gamma-ray bursts |
Friday, January 19, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Scanning Probe Nano-Lithography with SwissLitho’s NanoFrazor
Progress in nanotechnology depends on the capability to fabricate, position and interconnect nanometer-scale structures. However, existing conventional lithography techniques pose limitations and challenges related to resolution, operational costs, and more importantly, the lack of flexibility to pattern novel materials such as graphene and transition-metal dichalcogenides. Since the first patterning experiments performed with a scanning probe microscope in the late 1980s, scanning probe lithography has emerged as an alternative type of lithography for academic research that provides striking capabilities to pattern three-dimensional relief structures with nanoscale features; the fabrication of the smallest field-effect transistor; or the patterning of proteins with 10-nm feature size. In this presentation, I will introduce the innovative NanoFrazor, the first commercialized scanning probe lithography platform, and focus on its great potential in the emerging research on two-dimensional materials.
Speaker: Dr. Xiaorui Zheng (The City University of New York and SwissLitho)
About the speaker: Dr. Xiaorui Zheng was awarded the degree of PhD at Swinburne University of Technology (Australia) for his thesis entitled “The optics and applications of graphene oxide.” Prior to his appointment as SwissLitho Postdoc Fellow, Xiaorui worked as a research fellow at University of California, San Diego. Xiaorui’s current research interests lie in the nano-photonics of low-dimensional materials for both functional photonic and bio-medical applications using the NanoFrazor.
Friday, January 26, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Progress and Prospects at the McDonald Observatory
Taft Armandroff has served as Director of the McDonald Observatory since June 2014. His talk will include recent progress at McDonald Observatory on new instruments, telescope and instrument upgrades, and plans for the future. A number of enhancements are underway or complete, including a wide-field upgrade and powerful new instrument suite for the Hobby-Eberly 10-meter Telescope. The University of Texas at Austin (UT Austin) is a significant partner in the Giant Magellan Telescope (GMT) in Chile, which will be the world’s largest optical / infrared telescope when it begins commissioning in 2023. GMT plans and prospects and will be reviewed. UT Austin is developing instrumentation for GMT.
Speaker: Dr. Taft Armandroff (McDonald Observatory and UT Austin)
Friday, February 2, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Cancer Treatment Using High Frequency Electromagnetic Waves
The primary objective of this research endeavor is to study and to understand the natural physics phenomenon of electromagnetic resonance in one end closed cavity for the eventual purpose of cancer treatment. Radio Frequency waves are discharged into a coaxial cavity with a small amount (1.532 mL) of breast cancer cells (BT549) and the reflection as well as the power input is measured to determine the absorption power into the vitro cancer cell experiment. When the reflection of the RF waves from the loaded sample of cancer cells is at its lowest power, the RF Frequency is noted and seen to be approximately close to the resonant frequency of that cavity. This cavity can potentially be used as a control method of testing RF frequencies on various types of cancer cells, such as the available BT549 cancer cell line from Biology department. The determined frequency for 1.532 mL of sample article is found to be in the range of radio frequency, but there is much room for improvement depending on the coaxial cavity design such as length and the radii of the coaxial tubes which are under investigation. Some preliminary results are obtained which show that the electromagnetic waves induce cancer cell death via a process known as apoptosis. The results of the experiment will be presented in the colloquium talk.
Speaker: Dr. Muhammad Bhatti (UTRGV)
Friday, February 9, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Constraints on Milky Way halo formation using the most metal-rich halo stars
The Milky Way halo is halo contains mostly very old stars but may still be in the process of construction via cannibalism. While most surveys have concentrated on the most metal-poor stars in the halo we have taken the opposite tactic by looking at the most metal-rich (relatively) stars. Using 6-10 meter class telescopes such as the Magellan, VLT and HET we have constructed a sample of faint, outer halo, metal-rich, in-situ stars for which we have obtained chemical abundance ratios. These abundance ratios reveal their star formation history. Using the SDSS-IV APOGEE survey and combing those results with the early GAIA results we can construct a second set of metal-rich stars in the inner or local halo. We leverage the power of the APOGEE survey by contrasting the abundances of these halo stars against those found in the Milky Way thick disk and bulge. By looking at the results for the metal-rich inner and outer halo stars we speculate on the possible growth mechanisms for the Milky Way halo.
Speaker: Dr. Matthew Shetrone (McDonald Observatory & UT Austin)
About the speaker:
Undergraduate degree: University of Texas at Austin 1991
Graduate degree: University of California, Santa Cruz 1996
Post-doc: ESO fellow (Chile) 1996-1997
Resident Astronomer and Senior Research Scientist for Hobby-Eberly Telescope 1998-2018
Current Service Duties: Science Operations Manager, Deputy Facility Manager
Current Research Duties: APOGEE architect, HET Parallel Scientist
Friday, February 16, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
The Origin of Macroscale Superlubricity in Carbon Nanomaterials.
Tribological systems are an integral part of any moving mechanical assembly, from nanoscale microelectromechanical systems to macroscale automotive and aerospace applications. Minimizing friction and wear-related mechanical failures in order to allow superior performance and long-lasting operation of moving mechanical systems remains the one of today’s greatest challenges. Despite intense research efforts superlubricity, or near zero friction, has seldom been achieved at engineering scales or in practical systems. Much of the difficulty has often been due to the very complex physical, chemical, and mechanical interactions that occur simultaneously at sliding interfaces of mechanical systems. In this study we evaluate tribological performance of carbon nanomaterials [1-2], and demonstrate realization of superlubricity regime at macroscale in an all-carbon-based ensemble when diamond nanoparticles are mixed with graphene and slide against diamond-like carbon (DLC) surface [3]. We show that during sliding in dry atmosphere, graphene patches wrap around tiny diamond nanoparticles and form nanoscrolls, thus dramatically reducing the contact area with a perfectly incommensurate DLC surface. The coefficient of friction reaches ultralow values (0.004) thus demonstrating the long-lasting superlubric regime. This superlubricity is stable over range of temperature, load, and sliding velocity conditions. Our large-scale molecular dynamic simulations elucidate the mesoscopic link between nanoscale mechanics and macroscopic experimental observations. The highlighted carbon-based superlubricity provides a fundamental basis for developing universal friction mechanism and offers a direct pathway for designing smart frictionless tribological systems for practical applications of industrial interest.
References:
[1] D. Berman, et al., special issue in Diamond and Related Materials, 54, 91 (2015).
[2] D. Berman, et al., Materials Today 17 (2014) 31-42.
[3] D. Berman, et al., Science, 348 (2015) 1118-1122
Speaker:
Dr. Diana Berman (University of North Texas)
Dr. Diana Berman is currently an Assistant Professor in the Department of Materials Science and Engineering at University of North Texas. Dr. Berman received her BS in Applied Physics and Math from Moscow Institute of Physics and Technology and PhD in Physics from North Carolina State University. During her PhD she was working on the first generation of RF MEMS switches and the adhesion and wear associated failures in them. Since 2012 she worked as a PostDoctoral researcher and then as a Research Associate in the Center for Nanoscale Materials at Argonne National Laboratory on understanding the fundamental mechanisms of superlubricity, the vanishing friction and wear regime. Dr. Berman’s research interests are in synthesis and characterization of nanostructures, surfaces, and interfaces of ceramic and carbon-based materials for precise control and improvement of their physical properties and performance. Dr. Berman is specifically interested in tribological performance of materials, such as nanoscale contact evolution, interaction of material with environment, and macroscale friction and wear of sliding systems. Dr. Berman has published several high-impact-factor papers with over 1000 citations (in journals Science, Nature Communications, Advanced Functional Materials, ACS Nano, etc) and given several plenary and invited talks and presentations (2017 APS/CNM Annual Meeting, 2016 Gordon Research Conference in Tribology, 2015 Argonne Tribology Workshop). Her work was recognized with TechConnect National Innovation Awards at 2016 and 2017 TechConnect's annual World Innovation Conferences and Expo. Dr. Berman has been an organizer and chair of several Conferences and Workshops (1 st Tribology Workshop and Poster Presentation of STLE North Texas Chapter, STLE Annual Meetings 2016-2017, NDNC 2014, 2015 APS/CNM User Meeting Workshop, 2014 Argonne PostDoctoral Symposium).
Friday, February 23, 2018
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Geometrodynamics of Bloch electrons
Semiclassical dynamics of Bloch electrons in a crystal under slowly varying deformation is developed in the geometric language of a lattice bundle. Berry curvatures and gradients of energy are introduced in terms of lattice covariant derivatives, with the corresponding connections given by the gradient and rate of strain. A number of physical effects are discussed: an effective post-Newtonian gravity at band bottom, polarization induced by spatial gradient of strain, orbital magnetization induced by strain rate, and electron energy stress tensor.
Speaker: Dr. Qian Niu (The University of Texas at Austin)
Friday, March 2, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Micron-resolution Particle Image Velocimetry (μPIV) Analysis of Microfluidic Applications: Hydro-dynamically Confined Flows and Optoelectrokinetic Flows
Two microfluidic applications have been analyzed experimentally using micron-resolution particle image velocimetry (μPIV). The first application is microfluidic probe (MFP) that can be used to generate hydrodynamically confined microflows (HCMs) in open liquid environments. The MFP is immersed in a liquid reservoir and a flow is generated beneath the device. This allows for the application of microfluidic approaches to many biological applications that are typically performed in dishes and well plates. The direct measurement of in-plane velocity fields in the flow beneath an MFP will be presented. Secondly, the combination of AC electric fields and optical illumination allows for the easy and rapid creation of microvortex flows inside a microchannel for applications such as micropumping and micromixing. The manipulation and flow characterization of opto-electrokinetically generated microflows called twin opposing microvortex (TOMV) flows will be presented. This technique has the advantage of simpler construction than competing techniques. The measurement of the microvortex flows generated under non-uniform electric fields and a highly focused laser beam due to a unique characteristics of the TOMV flows will be presented.
Speaker: Dr. Choongbae Park (Texas A&M University - Kingsville)
Friday, March 9, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
PALFA Discovery of a Highly Relativistic Double Neutron Star Binary
In August 2017, the PALFA survey discovered a pulsar (PSR J1946+2052) with a 17 ms spin period in a 1.88 hour, eccentric (e~0.06) orbit with a ~1.2 solar mass companion. Soon after discovery, we used the Jansky Very Large Array to localize PSR J1946+2052 to a precision of 0.09 arcseconds using a new phase binning mode. This improved position allowed for us to measure a spin period derivative which indicates the pulsar has a weak magnetic field compared to "normal" pulsars and therefore has been recycled through mass transfer from a companion. This combined with the orbital eccentricity lead to the conclusion that PSR J1946+2052 is in a DNS system. Among all known radio pulsars in DNS systems, PSR J1946+2052 has the shortest orbital period and the shortest estimated merger timescale, 46 Myr; at that time it will display the largest spin effects on gravitational-wave waveforms of any such system discovered to date. In this talk, I will describe the PALFA survey, the discovery of J1946+2052, and discuss what is currently known about the system. I will also discuss the future plans for this pulsar system including other relativistic orbital parameters that we expect to be able to detect in the coming years.
Speaker: Dr. Kevin Stovall (The Univ. of New Mexico, National Radio Astronomy Observatory, Socorro)
Friday, March 23, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
On Ising's model of ferromagnetism
The 1D Ising model is a classical model of great historical significance for both classical and quantum statistical mechanics. Developments in the understanding of the Ising model have fundamentally impacted our knowledge of thermodynamics, critical phenomena, magnetism, conformal quantum field theories, particle physics, and emergence in many-body systems. Despite the theoretical impact of the Ising model there have been very few good 1D realizations of it in actual real material systems. However, it has been pointed out recently, that the material CoNb2O6, has a number of features that may make it the most ideal realization we have of the Ising model in one dimension. In this talk I will discuss the surprisingly complex physics resulting in this simple model and review the history of "Ising’s model” from both a scientific and human perspective. In the modern context I will review recent experiments by my group and others on CoNb2O6. In particular I will show how low frequency light in the THz range gives unique insight into the tremendous zoo of phenomena arising in this simple material system.
Speaker: Dr. Peter Armitage (Johns Hopkins University)
Friday, April 20, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Single molecule DNA-protein interactions: Battling retroviruses and controlling genome access
Optical tweezers allow us to probe the interactions of proteins with single DNA molecules and apply very small forces. Measurement of force-dependent DNA conformations allows us to quantify interactions that govern cellular function. Here we investigate the DNA interactions of human APOBEC3G, an innate antiviral immunity protein that functions as a cytidine deaminase. Our results show that the process of interconversion between monomeric and dimeric states regulates APOBEC3G’s deamination-dependent and deamination-independent inhibition of HIV-1 replication. I will then discuss the role of eukaryotic HMGB proteins in determining nucleosome accessibility, an important mechanism for regulating protein expression. We construct an array of nucleosomes on a single DNA molecule, measuring nucleosome stability in the presence of HMGB proteins. We find significant unwrapping of nucleosomes due to HMBG-DNA binding, the extent of which differs between different types of HMGB proteins. The extent of observed destabilization correlates with the presence of nucleosome-free regions in cells, revealing distinct functions for regulation of nucleosome accessibility by different HMGB proteins.
Speaker: Dr. Mark C. Williams (Northeastern University)
Friday, September 7, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Finding Nano-blocks to Control Light
Metasurfaces have emerged in recent years as a platform for designing subwavelength-thick optical components. Such designer optical interfaces introduce spatially-varying optical responses which can mold the wavefronts of light. The reduced dimensionality of optical metasurfaces opens new physics and leads to novel functionalities distinctly different from those in three-dimensional optical materials. In this talk I will introduce the basic concept of metasurfaces to control light propagation in free space and in optical waveguides. Furthermore, I will present our recent experimental demonstration of a new metasurface platform with hyperbolic materials to control light localized on the surface. These metasurfaces can be the main building blocks in mid-/far infrared flat optics and integrated nanophotonics.
Speaker: Dr. Myoung-Hwan Kim (UTRGV)
Friday, September 14, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Biofilms and Mechanics: Forces in Microbial Community
Speaker: Dr. Ahmed Touhami (UTRGV)
Friday, September 21, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Kinesin-14s: Moving into a New Paradigm
Kinesin-14s are microtubule-based motor proteins that play important roles in cell division. They were originally thought to be minus-end-directed nonprocessive motors that exhibit directional preference toward the microtubule minus ends in multi-motor ensembles but are unable to generate processive (continuous) motility on single microtubules as individual motors. During the past five years, we and others have discovered several “unconventional” kinesin-14 motors that all contain the ability to generate processive motility as individual motors on single microtubules. In this talk, I will present a series of unexpected yet exciting findings from my lab that have markedly expanded current view of the design and operation principles of kinesin-14 motors.
Speaker: Dr. Weihong Qiu (Oregon State University)
Friday, September 28, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Correlating the Synthesis-Structure-Property Relationship of Complex Metal Oxide Nanomaterials
Understanding the synthesis-structure-property relationship of functional materials has paramount importance in order to meet the materials needs and challenges of our evolving and expanding society. Complex metal oxides and their nanomaterials have attracted intensive attention due to their chemical composition and structural flexibility, more importantly, their fascinating properties and broad application potentials. In this colloquium, after a brief overview, two types of functional metal oxides will be discussed to exemplify our recent research effort within this context. As an example of advanced (photo)electrochemical materials, it is expected that delafossites with CuIMIIIO2 composition could serve as potential candidates for cost-effective and active electrode material based on cyclic voltammetry and electrochemical impedance spectroscopy measurements along with their onset potential, current density, Tafel slope, charge transfer resistance, and stability. For luminescent materials useful for solid-state lighting, X-ray scintillators, and bioimaging, focus will be placed on our recent studies on the controllable synthesis of A2M2O7 nanoparticles, and investigation of the morphology and composition influence on their photoluminescence and radioluminescence. We have achieved substantial tunability of their particle size, crystal phase, and more importantly, optical properties. In sum, advanced electrochemical and optical materials of complex metal oxides offer bright promise of producing innovative advances across multiple technologies, and thus will continue impacting our lives in substantial ways.
Speaker: Dr. Yuanbing Mao (UTRGV, Chemistry)
Friday, October 5, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Understanding of Galaxies Using the Four Corner Stellar Populations in the Color – Magnitude Diagram
The Four Corner Stellar Populations in the Color – Magnitude Diagram that I will present in the talk are the blue horizontal-branch stars on the upper left, the tip of the red giant branch stars and the thermally pulsing asymptotic giant branch stars on the upper right, the main-sequence knee feature on the lower right, and the white dwarf cooling sequence on the lower left. The blue horizontal-branch stars, the main-sequence knee feature, and the white dwarf cooling sequence play important roles for the age estimation of star clusters and the tip of the red giant branch stars and the thermally pulsing asymptotic giant branch stars are of importance for the distance measurement of galaxies. I will conclude with the plan for the CSI Galaxies (Center for Stellar populations In Galaxies) at the UTRGV.
Speaker: Dr. Hyun-chul Lee (UTRGV)
Friday, October 12, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Mathematical models and computations for ultrashort laser pulse propagation
The most recent advances in nonlinear optics include the generation and applications of ultra-short optical pulses, whose time duration is typically of the order of femtoseconds. In this talk, I will present a newly proposed model for describing the propagation of ultra-short pulses in femtosecond regime with a few cycles: the complex short pulse (CSP) equation and its coupled two-component generalization for polarized light in birefringent media. This newly proposed model can be viewed as an analogue, in ultra-short pulse regime, of the nonlinear Schrödinger (NLS) equation and coupled nonlinear Schrödinger (CNLS) equation. From the point view of physics, they are higher order models beyond slowly varying envelop approximation (SVEA). On the other hand, they are completely integrable, more amenable to rigorous analysis and possessing various exact solutions, from the point view of mathematics. Starting from the Maxwell equation, I will firstly derive the complex short pulse and coupled complex short pulse equations. Then I will construct multi-soliton solutions of both bright and dark type, as well as the rogue wave solutions. Secondly, I will propose integrable semi-discrete analogues of these models, where the spatial variable takes values in a lattice, while the integrability of the resulting equations is preserved. We will construct their various exact solutions and apply these semi-discrete model equations as a novel numerical method: integrability-preserved and self-adaptive moving mesh method for the simulations of the original model equations.
Speaker: Dr. Baofeng Feng (UTRGV, Math)
Friday, October 19, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Multi-particle bound states in a two-dimensional semiconductor
Since the mechanical isolation of graphene – a single atomic layer of carbon atoms arranged in a chicken-wire pattern – in 2004, the studies of atomically-thin two-dimensional (2D) crystals have evolved into a vibrant field with many interesting discoveries and surprises. In the talk, I will discuss our recent investigation of multi-particle bound states in monolayer tungsten diselenide, a 2D semiconductor. The valley and spin degrees of freedom make these bound states highly versatile, and the inherent Coulomb interaction of the high-quality samples we fabricate enables us to observe light emission due to two-, three-, four- and five-particle bound states. We unambiguously determine the spin and valley composition of these states. The luminescence further reveals 2s, 3s and 4s excited Rydberg states in high magnetic fields up to 31 Tesla. These studies pave way for new opportunities to build valleytronic quantum devices, and quantum communication platforms harnessing unique TMDC properties.
Speaker: Dr. Jun Yan (University of Massachusetts Amherst, Physics)
Friday, October 26, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Scanning Diffracted-Light (SDL) Imaging
Common cameras permit to obtain intensity images of objects; thus, are only sensible to the amplitude of the electric field. However, the phase of the electric field also carries information about the world around us. Intensity images of transparent objects reveal less about the structure of the objects than phase images. For instance, a large variety of living cells are clear; therefore, several phase-recovery imaging techniques have been developed for imaging the phase of light that passes through transparent tissues. The multitude of bright objects visible in the firmament are separated by a transparent and immense medium. The intensity images collected by telescopes give us amazing images of the bright objects filling our Universe. However, intensity images may not tell the complete history because intensity images carry few information about the transparent immensity that separates visible stars, galaxies, and mega structures. I will talk about a novel phase-recovery imaging technique that may allow developing a telescope for obtaining phase- images of the Cosmos. I will also discuss how SDL imaging may also allow developing the first phase-recovery optical nanoscope.
Speaker: Dr. Luis Grave de Peralta (Texas Tech University, Physics)
Friday, November 9, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Physics of Signal Transduction in Living Cells: Conformational Switch, Activation and Clustering
Living cells sense mechanical signals, and respond actively by changing their phenotype. This process, termed as cellular mechanotransduction, is mediated by a combination of biochemical and biophysical mechanisms via mechanically induced changes in the structure and function of specific molecules and molecular complexes. Our specific attention is on the role of three macromolecular systems in cellular mechanotransduction, namely the integrin-mediated focal adhesions bridging the cell with the extracellular matrix (ECM), and linkers of the nucleoskeleton and cytoskeleton (LINC complexes), and the nuclear pore complex (NPC) at the interface between the cytoplasm and nucleus. Focal adhesions are the immediate sites of cell interaction with the ECM, and as such they play a key role in mechanosensing and mechanotransduction at the edge of the cell. LINC complexes physically link the cytoskeleton and nucleoskeleton to regulate force transmission to the nucleus; their direct associations with focal adhesions through filamentous actin bundles results in ultrafast mechanotransduction. Nuclear pores could also play a role in the overall process of cellular mechanotransduction by exquisitely controlling the material transport in and out of the nucleus, thereby regulating gene expression and protein synthesis. In this seminar, I will present some of our recent efforts aimed at better understanding of these interconnected molecular systems in the context of cellular mechanotransduction.
Speaker: Dr. Mohammad R. K. Mofrad (UC Berkeley, Bioengineering and Mechanical Engineering)
Friday, November 16, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
From Nanoscale Emitters to Photonic Integrated Circuits
A crucial component in high-performance photonic integrated circuits (ICs) and other chip-scale photonic systems is an on-chip light source that is efficient, economical, silicon (Si)- compatible, and electronically addressable. In this talk, I will cover two types of light sources with the potential to be inserted into photonic ICs: III-V nano-antenna and perovskite microlasers. I will further discuss emerging physics and applications that can be enabled by these material systems, including topological states and unidirectional edge-modes for robust data transport, and metamaterials with hyperbolic dispersion for super-resolution imaging.
Speaker: Dr. Qing Gu (UT Dallas, Electrical and Computer Engineering)
Friday, November 30, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Data analysis methods for gravitational wave searches from binary inspirals and gamma-ray bursts
We investigate and develop data analysis methods for gravitational wave searches from binary inspirals and gamma-ray bursts. The first technique is a low- latency fully coherent network analysis of gravitational wave detector data to infer information on compact binary coalescence. It uses the stationary phase approximation, optimizes using particle swarm optimization, and an implementation is developed for high-performance computing. The second technique concerns gamma-ray bursts. Given a set of observed astrophysical events, such as gamma ray bursts, it is possible to combine gravitational wave detector data that is temporally associated with these events to infer population properties of the sources. A method is presented for better integration of available non-gravitational wave data - mainly from the electromagnetic signature of the events - into such population studies. Given a population model for the gravitational wave emission properties of a class of astrophysical sources, the method combines gravitational and non-gravitational wave data into a joint likelihood function and obtains maximum likelihood estimates of the model parameters. A toy model is used to illustrate the application of the method.
Speaker: Marc Eric Normandin (UTRGV, Physics)
Date
|
Speaker
|
Institution
|
Title
|
Jan 20
|
Karl Gebhardt
|
University of Texas at Austin
|
From black holes to dark energy, using the eyes of Texas
|
Feb 3
|
Martin Mittendorff
|
University of Maryland, College Park
|
Graphene and THz radiation: time resolved spectroscopy and applications
|
Feb 17
|
Junichiro Kono
|
Rice University
|
Dicke phenomena in condensed matter
|
Mar 3
|
Ohad Shemmer
|
University of North Texas
|
Multiwavelength diagnostics of quasar accretion power
|
Mar 10
|
Tsampikos Kottos
|
Wesleyan University
|
Non-Hermitian wave transport: new possibilities and challenges
|
Apr 7
|
Bibhudutta Rout
|
University of North Texas
|
Materials analysis and modifications at micro-nanoscale using ion beams
|
Apr 24
|
JaeHoon Jung
|
Texas A&M University
|
Electron Tomography: integrating nanoscale subcellular structures and their functions
|
Apr 28
|
Ryan Suess
|
U.S. Naval Research Laboratory
|
Tuning the functionality of materials with reversible phase transitions
|
May 1
|
HyeongJun Kim
|
Harvard Medical School
|
The power of single: Revealing mechanisms of molecular machines in single-molecule imaging
|
Sep 15
|
Warren Skidmore
|
Thirty Meter Telescope
|
The thirty meter telescope observatory: the next generation ground based optical/infra-red observatory
|
Sep 22
|
Marek Szczepanczyk
|
Embry-Riddle Aeronautical Univ.
|
Core-collapse supernova science with advanced detectors and beyond
|
Sep 29
|
Fredrick Jenet
|
UTRGV
|
NewSpace: The dawn of the next space age
|
Oct 13
|
Andreas Hanke
|
UTRGV
|
Kinetic Pathways of topology simplification by type-II topoisomerases in knotted, supercoiled DNA
|
Oct 20
|
Philip Kim
|
Harvard University
|
Materials in 2-dimension and beyond: platform for novel electronics and optoelectronics
|
Oct 27
|
Manoj Peiris
|
UTRGV
|
Towards Violation of Classical Inequalities using Quantum Dot Resonance Fluorescence
|
Nov 3
|
Michele Zanolin
|
Embry-Riddle Aeronautical Univ.
|
Multimessenger astronomy for Core Collapse Supernovae
|
Nov 10
|
Hasina Huq
|
UTRGV
|
Growth and Characterization of Gallium Based Thin Films for Bio Sensors Applications
|
Nov 17
|
Guru Naik
|
Rice University
|
Hot nanophotonics: From hot carriers to hot thermal emitters
|
Dec 1
|
Jaehong Park
|
Lawrence Berkeley National Laboratory
|
Plasma Physics using Particle-in-Cell Simulations: Applications to Space and Laboratory
|
Friday, March 10, 2017
Time: 10:50am - 12:20pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Non-Hermitian Wave Transport: New possibilities and challenges
While there is absolutely no doubt as to the usefulness of gain mechanisms in order to boost signals and transfer information, loss on the other hand, is typically considered an “anathema” – a feature to be avoided if at all possible - since it degrades the efficiency of the structures employed to perform useful operations on these signals. Currently however, an alternate viewpoint is emerging aiming to manipulate absorption in classical wave systems, and via a judicious design of the medium impedance profile, to achieve new classes of synthetic structures with altogether new physical behavior and novel functionality. We shall present some example cases where manipulation of loss can find practical applications and we shall provide our vision of the future of Non-Hermitian wave transport.
Speaker: Dr. Tsampikos Kottos (Wesleyan University)
Friday, April 7, 2017
Time: 10:50am - 12:20pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Materials analysis and modifications at micro-nanoscale using ion beams
Ion beams with energies from a few keV to MeV have been used for materials analysis, synthesis and modifications in a wide range of fields involving metallurgy, semiconductors, to biomaterials. Recent advances in the manufacturing process, ion optics theory and computer control systems have led to the development of high spatial resolution (sub-micro meter) High Energy Focused Ion Beam Systems mainly using H+ or He+ ions. These ion beams allow quantitative elemental analysis of a wide range of elements with unprecedented detection sensitivity in a short time, especially for physiologically important metals (ppm level). Microscopic multi-element images of a sample are simultaneously provided. Heavy ions of broader diameter have been used for synthesis of micro-nanostructures at near surfaces to layers buried deep below the substrate surfaces, with applications in many different areas, spanning from the microelectronic industrial production to the synthesis of new materials system (e.g. thin layers ~30 μm of Si for solar cell applications). In this presentation, we will be illustrating examples of quantitative multi-dimensional trace elemental analysis in many systems from semiconductors to biological materials at cellular levels. Also examples of multi-dimensional metal-semiconductor nano-structures synthesized in semiconductors will be presented.
Speaker: Dr. Bibhudutta Rout (University of North Texas)
Monday, April 24, 2017 (Brownsville Campus)
Time: 11:00am - 12:00pm
Location: Cavalry Conference Room
*Lunch/Meet with students 12:00pm - 1:00pm
Tuesday, April 25, 2017 (Edinburg Campus)
Time: 3:10pm - 4:10pm
Location: EPHYS 1.119
*Meet with students 4:10pm - 4:40pm
Electron Tomography: Integrating nanoscale subcellular structures and their functions
Electron tomography has been increasingly used to provide 3-dimensional information of subcellular organelles and macromolecular complexes with an exceptional resolution. Such electron tomography studies on synapses have provided valuable findings and novel insight for a comprehensive understanding of how the nervous system functions. In this talk, I present my electron tomography study on synaptic vesicle priming, a crucial regulatory step to mediate synaptic transmission. My work first quantified the spatial relationship of synaptic vesicles with the presynaptic membrane and the active zone material commonly observed at the active zone with a few nanometer spatial resolution, revealing strong evidence that the contact area of the synaptic vesicle with the presynaptic membrane is a structural correlate of synaptic vesicle priming and that the area is regulated by the active zone material. These findings will be of interest to anyone studying aspects of synaptic physiology that govern how the nervous system performs its various specialized tasks in normal and disease states. Such quantitative electron tomography approaches will also be useful to obtain nanometer-scale 3-dimensional information of other biological and non-biological materials because of its general applicability.
Speaker: Dr. JaeHoon Jung (Texas A&M University, Department of Biology)
Friday, April 28, 2017
Time: 10:50am - 12:20pm
Location: BMAIN 1.224 (Brownsville), EACSB 1.104 (Edinburg)
Tuning the Functionality of Materials with Reversible Phase Transitions
There has been considerable interest in vanadium dioxide (VO2) due to its sharp, insulator to metal transition (IMT) that produces highly variable optical and electrical properties. The IMT is coupled to a monoclinic to tetragonal structural change at 68 oC, that can be induced via the application of external stimuli such as thermal, chemical, stress/strain, and electrical excitations. The changeable nature of the material response makes VO2 an attractive candidate for numerous applications such as terahertz emitters, smart window coatings, and ultrafast switches. In this talk we will discuss the properties of epitaxial VO2 films grown by laser pulse deposition (PLD) and report the effect of PLD growth conditions on the stress/strain state of the VO2 layer. Strain engineering results in dramatic changes to the electrical and optical properties of the film, revealing both interesting IMT physics as well as a means for tailoring the response of VO2-based devices. In the second part of the talk, active terahertz devices fabricated from VO2 films will be discussed.
Monday, May 1, 2017 (Brownsville Campus)
Time: 11:00am - 12:00pm
Location: Cavalry Conference Room
*Lunch/Meet with students (Q&A): 12:00pm - 1:00pm at Cavalry Conference Room
Tuesday, May 2, 2017 (Edinburg Campus)
Time: 3:00pm - 4:00pm
Location: EPHYS 1.119
*Meet with students (Q&A): 4:00pm - 4:30pm at EPHYS 1.119
The Power of single: Revealing mechanisms of molecular machines in single-molecule imaging
The advent of single-molecule techniques has enabled biophysicists to obtain in-depth information by looking into “individual” biological molecules. By discussing single-molecule biophysics studies on two protein machines (Myosin VI cellular motor protein and SMC) as examples, we show that single-molecule techniques based on physics principles provide a powerful toolset in answering important biological questions. For example, SMC (Structural Maintenance of Chromosomes) is a huge protein machine playing essential roles in chromosome condensation and DNA repair. Despite intensive efforts, it has remained unclear how SMCs structure DNA and how their mechanochemical cycle regulates their interactions with DNA. We combined force-based multiplexed single-molecule tools (e.g. flow-stretching assay) with fluorescence-based imaging, and visualized how a single Bacillus subtilis bacterial SMC (BsSMC) interacts with flow-stretched DNAs. We find that a single BsSMC can vary its initial interaction with DNA – switching between being static and mobile. On the other hand, multiple BsSMCs form distinct clusters that are capable of compacting DNA by both bending and bridging two different segments of DNA. During these steps, adding ATP (cellular energy source) leads to faster compaction, but is not required. These mechanistic details would not have been revealed without investigating individual molecules.
Speaker: Dr. HyeongJun Kim (Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology)
Friday, September 15, 2017
Time: 12pm - 1pm
Location: BBRHB 1.222 (Brownsville), EACSB 1.106 (Edinburg)
The Thirty Meter Telescope Observatory: The Next Generation Ground Based Optical/Infra-Red Observatory
After a construction status update, I will describe how the telescope design has been developed to support a broad range of observing capabilities and how the observatory is being engineered. I'll discuss some of the observational capabilities that the Thirty Meter Telescope will provide and some of the areas of study that will benefit from the TMT's capabilities, specifically synergistic areas with new and future proposed astronomical facilities. Finally, I will describe the avenues through which astronomers can provide input or become involved in the planning of the project, the potential NSF partnership, prioritizing the development of 2nd generation instruments and directing the scientific aims for the observatory.
Speaker: Dr. Warren Skidmore (Thirty Meter Telescope)
Friday, September 22, 2017
Time: 12pm - 1pm
Location: BBRHB 1.222 (Brownsville), EACSB 1.106 (Edinburg)
Core-Collapse Supernova Science with advanced detectors and beyond
Core-Collapse Supernovae are the spectacular and violent deaths of massive stars. The detection of Gravitational Waves from the initial moment of a collapsing star could deliver the next revolution in understanding space-time and matter in extreme conditions. In my presentation, I will give an overview of searches targeting supernova signals in initial LIGO and Virgo data. I will discuss some of the current efforts to detect Gravitational Waves with advanced detectors, reconstruct the waveforms and extract physical information, like the dynamics of revived shock. Additionally, I will give a brief overview of the studies about extracting physics from collapsing stars with the third-generation interferometers.
Speaker: Marek Szczepanczyk (Embry-Riddle Aeronautical University)
Friday, September 29, 2017
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
NewSpace: The dawn of the next space age
Space is no longer in the hands of big government. Over the last decade, there has been a concerted effort to foster the privatization of space exploration. This is being driven by many sides, from governmental policies to budding entrepreneurs. This presentation will introduce the concept of NewSpace, the new space age, discuss recent events that are shaping the industry, and how UTRGV’s Center for Advanced Radio Astronomy, home of the STARGATE program, is creating opportunities for UTRGV faculty, staff, and students to play a role the NewSpace age as a leading center of near and deep space exploration.
Speaker: Dr. Fredrick Jenet (The University of Texas Rio Grande Valley)
Friday, October 13, 2017
Time: 12pm - 1pm
Location: BBRHB 1.222 (Brownsville), EACSB 1.106 (Edinburg)
Kinetic Pathways of topology simplification by type-II topoisomerases in knotted, supercoiled DNA
The topological state of covalently closed, double-stranded DNA is defined by the knot type, K, and the linking number difference from relaxed DNA, ΔLk. DNA topoisomerases are essential enzymes that regulate topological states of DNA in vivo: type-I topoisomerases (topo-Is) change ΔLk, thereby regulating the torsional tension, whereas type-II topoisomerases (topo-IIs) change both (ΔLk, K) by passing one DNA helix through another. A critical biological function of type-II enzymes is the elimination of knots in DNA because their presence impedes transcription and replication. It has been a long-standing puzzle how small type-II enzymes select passages that unknot large DNA molecules, since topology is a global property which cannot be determined by local DNA-enzyme interactions. Previous studies addressing this question have focused on the equilibrium distribution P(ΔLk, K). Motivated by the fact that topo-IIs reduce the knotting level below equilibrium at the expense of ATP hydrolysis, we set out to study topoisomerase activity in the framework of non-equilibrium thermodynamics. We consider the dynamics of transitions in a network of topological states (ΔLk, K) induced by type-II and type-I action by solving the master equation for the time-dependent probability distribution P(ΔLk, K; t). We fully characterize non-equilibrium steady states generated by injecting DNA molecules in a given topological state in terms of stationary probability distributions and currents in the network. This allows us, for the first time, to predict detailed kinetic pathways of topoisomerase action as a function of geometry of the enzyme. In particular, we find that unknotting activity of topo-II is significantly enhanced in DNA molecules which maintain a supercoiled state with constant torsional tension; this is relevant for bacterial cells in which the torsional tension is maintained by a homeostatic mechanism using topo I and DNA gyrase.
Speaker: Dr. Andreas Hanke (The University of Texas Rio Grande Valley)
Friday, October 20, 2017
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Materials in 2-dimension and beyond: platform for novel electronics and optoelectronics
Heterogeneous interfaces between two dissimilar materials are an essential building block for modern semiconductor devices. The 2-dimensional (2D) van der Waals (vdW) materials and their heterostructures provide a new opportunity to realize atomically sharp interfaces in the ultimate quantum limit for the electronic and optoelectronic processes. By assembling atomic layers of vdW materials, such as hexa boronitride, transition metal chalcogenide and graphene, we can construct atomically thin novel quantum structures. Unlike conventional semiconductor heterostructures, charge transport in of the devices is found to critically depend on the interlayer charge transport, electron-hole recombination process mediated by tunneling across the interface. We demonstrate the enhanced electronic optoelectronic performances in the vdW heterostructures, tuned by applying gate voltages, suggesting that these a few atom thick interfaces may provide a fundamental platform to realize novel physical phenomena. In this presentation, we will discuss several recent development of electronic and optoelectronic properties discovered in the van der Waals heterostructures, including hydrodynamic charge flows, cross-Andreev reflection across the quantum Hall edges states, and interlayer exciton formation and manipulations.
Speaker: Dr. Philip Kim (Harvard University)
Friday, October 27, 2017
Time: 12pm - 1pm
Location: EACSB 1.106 (Edinburg), BSABH 1.104 (Brownsville)
Towards Violation of Classical Inequalities using Quantum Dot Resonance Fluorescence
With their atom-like properties, semiconductor quantum dots have attracted considerable interest recently, ranging from fundamental studies of quantum optics to advanced applications in the field of quantum information science. In this talk, we will discuss some experimental progress towards the understanding of light-matter interactions that occur beyond well-understood monochromatic resonant light scattering processes in semiconductor quantum dots. First, we will describe the measurements of resonance fluorescence under bichromatic laser excitation. Under these conditions, the scattered light exhibits a rich spectrum containing many spectral features that lead to a range of nonlinear multiphoton dynamics. Second, we will present about the light scattered by a quantum dot in the presence of spectral filtering. Finally, Franson-interferometry will be discussed using spectrally filtered light from quantum dot resonance fluorescence which paves the way for producing single time-energy entangled photon pairs that could violate Bell's inequalities.
Speaker: Dr. Manoj Peiris (The University of Texas Rio Grande Valley)
Friday, November 3, 2017
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Multimessenger astronomy for Core Collapse Supernovae
In this talk I will review the astrophysics ingredients, theoretical and observational, for studying Core Collapse Supernovae with Gravitational Waves, Neutrinos and EM observations. Particular focus will be devoted to the landscape of morphologies of the expected GW signals as well as SN dedicated GW detection methodologies.
Speaker: Dr. Michele Zanolin (Embry Riddle Aeronautical University)
Friday, November 10, 2017
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Growth and Characterization of Gallium Based Thin Films for Bio Sensors Applications
The properties of Aluminum Gallium Nitride (AlGaN), Gallium Nitride (GaN) and Gallium Oxide (GaO) thin films on different substrates are studied in this research. There have been great accomplishments for building layers of these materials for biosensors, opto-electronics and high power devices. A magnetron sputtering system is used to create the thin-films on silicon (Si), sapphire (Al2O3) substrates. The electrical characteristics and the surface morphology of the thin films are investigated by using a X-ray photo electron spectroscopy, a scanning electron microscopy and an atomic force microscopy. The methodology to fabricate the wide band gap (WBG) semiconductor thin films at lower pressure with better crystal quality is still challenging.
Speaker: Dr. Hasina Huq (The University of Texas Rio Grande Valley)
Friday, November 17, 2017
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Hot nanophotonics: From hot carriers to hot thermal emitters
Nanophotonics has enabled extreme control on the flow of light leading to revolutionary applications including imaging, and chemical sensing. Not only does nanophotonics allow the extreme control on light flow, but also on heat flow. The interplay between light and heat at the crossroads of nanophotonics leads to many promising applications in energy conversion. In this talk, I will describe devices that allow efficient renewable energy harvesting by achieving extreme anisotropy and asymmetry. First, I will discuss how hot carriers – commonly considered loss pathways in plasmonic devices – can convert low energy photons to higher energies. This new upconversion scheme promises to be broadband, tunable, and an order of magnitude more efficient than existing solid-state upconversion schemes. Next, I will describe a renewable energy harvesting device based on nanophotonic selective thermal emitters. I will show how semiconductor nanostructures enable high efficiency waste heat recovery. Finally, I will show how thermal emitters based on extremely anisotropic materials – carbon nanotubes – can revolutionize heat to electricity conversion. The extreme control on light and heat flow would open new avenues for addressing one of the greatest technological challenges of our time – providing clean energy to the world.
Speaker: Dr. Guru Naik (Rice University)
Friday, December 1, 2017
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Plasma Physics using Particle-in-Cell Simulations: Applications to Space and Laboratory
Particle-in-cell (PIC) simulations are widely used tools to study plasmas and their interaction with the electric and magnetic fields. Because PIC codes directly solve the fundamental equations: relativistic Newton’s equations + the Maxwell equations, the simulations can describe the plasma behavior more accurately than any other codes. In this colloquium, I will talk about the astrophysical and the laboratory applications of PIC simulations: (1) collisionless shocks, (2) magnetic reconnection, (3) laboratory astrophysics, and (4) laser based ion acceleration. These are different subjects but are related by sharing the same goal, “particle energization”. Collisionless shocks are generated by interactions between fast moving plasma flows. In collisionless shocks, I will explain under what processes the electrons and the protons are accelerated [Park et al. PRL 114, 085003 (2015)]. Magnetic reconnection is a topological rearrangement of the magnetic field where the flux-freezing breaks down. I will present how the electrons are accelerated in magnetic reconnection to explain the observed electron spectrum in solar flares. Finally I will introduce some laboratory applications of PIC simulations. I will present our recent progress to find a collisionless shock in the laboratory experiment. Also, I will talk about our recent simulation and experimental studies of laser driven ion acceleration done in LBNL.
Speaker: Dr. Jaehong Park (Lawrence Berkeley National Laboratory)
Date
|
Speaker
|
Institution
|
Title
|
Info
|
Feb 12
|
Laura Chomiuk
|
University of Michigan
|
Black holes in Globular Clusters
|
|
Mar 4
|
Eva Noyola
|
McDonald Observatory at UT Austin
|
Intermediate Mass Black-Holes in Globular Clusters
|
|
Apr 29
|
Caitlin Casey
|
UT Austin
|
The Universe's most extreme star-forming galaxies
|
|
Sept 9
|
Matthew Benacquista
|
UTRGV
|
Making Massive Black Hole Binaries
|
|
Sept 16
|
Hyun-Chul Lee
|
UTRGV
|
Stellar Populations in Star Clusters and Galaxies
|
|
Sept 30
|
Teviet Creighton
|
UTRGV
|
If Earth falls, could interstellar travel be our salvation?
|
|
Oct 7
|
Nicolas Pereyra
|
UTRGV
|
On the disk wind mass loss rates in QSOs
|
|
Oct 14
|
Soumya Mohanty
|
UTRGV
|
Pulsar timing array based search for supermassive black hole binaries in the SKA era
|
|
Oct 28
|
Nanfang Yu (host: Dr. Kim)
|
Columbia University
|
Flat Optics
|
|
Nov 4
|
Nicholas Dimakis
|
UTRGV
|
The search for high efficient fuel cell anode catalysts: The Pt-Ru-Os-Ir Quaternary Alloy
|
|
Nov 11
|
Madhab Pokhrel
|
UTRGV
|
Synthesis and spectroscopic characterization of rare earth doped optical materials and their potential applications
|
|
Dec 2
|
John Cerne (host: Dr. Kim)
|
State Univ. of New York at Buffalo
|
Shedding new light on graphene, semiconductors, and high temperature superconductors using polarized infrared magneto-spectroscopy
|
Contact Us
Nicholas Dimakis
Chair, Department of Physics and Astronomy
Office: BINAB 2.115, ESCNE 1.606A
Email: nicholas.dimakis@utrgv.edu
Phone Brownsville: (956) 882-6679
Phone Edinburg: (956) 665-2041
Administrative Assistant
Department of Physics and Astronomy
Office: BINAB 2.102, ESCNE 1.606A
Phone Brownsville: (956) 882-6779
Phone Edinburg: (956) 665-3136
Colloquium 2015
Date | Speaker | Institution | Title | Info |
May 22 | Robert Stone | UTB | A study in the characterization of non-stationarity in gravitational wave detectors during science data collection. | abstract |
June 10 | Suresh Doravari | LIGO Livingston | Performance improvements in aLIGO Optical Levers | abstract |
June 12 | Mario Diaz | UTB | The TOROS Observatory | abstract |
June 19 | Juan Guevara | UTB | Biophysics | abstract |
June 26 | Joe Romano | UTB | MC Escher | abstract |
July 10 | Luo Jing | UTSA | Pulsar Timing Arrays | abstract |
July 17 | Bruno Sanchez | Astronomical Observatory of Cordoba | Real vs Bogus: Machine Learning for transient astronomy | abstract |
July 24 | Sourabh Nampalliwar | UTB | Gravitational radiation during plunge - a Green's function approach | abstract |
Aug 21 | Sanjeev Dhurandhar | IUCAA | The cross-correlation search for stochastic and continuous gravitational wave sources | abstract |
Jan 16 | Ted Hodapp | American Physical Society | Promoting Diversity in Physics Graduate Education:APS Bridge Program | abstract |
Feb 4 | Martin Beroiz | UTB | Optical follow-up for Gravitational Wave Events | abstract |
Feb 4 | Lucas Macri | Texas A & M | The Hubble constant in the era of precision cosmology | abstract |
Feb 6 | Mike Disney | University of Cardiff | Hidden galaxies and common sense | abstract |
Feb 20 | Matt Abernathy | LIGO Caltech Lab | Recent Results in bulk and shear Investigations | abstract |
Mar 4 | Sourabh Nampalliwar | UTB | The nature of spherical collapse and a study of black hole dynamics | abstract |
Apr 10 | Alex Zakhidov | Texas State University | Physics of Organic Semiconductor Devices: Materials, Fundamentals, Technologies and Applications | abstract |
Apr 24 | Junyu Dong | UTB | Underwater 3D surface reconstruction based on photometric stereo and laser sectioning | abstract |
Apr 24 | Preston O. Broadfoot | UTRC | What UTRC can offer for faculty members (including researchers)? | abstract |
May 1 | Undergraduate Research Seminar | UTB | Final Research Presentations | abstract |
Sept 3 | Myoung Hwan Kim | Columbia University | Molding light with flat optics | abstract |
Sept 10 | Huidong Zang | Los Alamos National Lab | Magnetic and Optical Studies on charge transfer and charge separation in organic/inorganic hybrid Solar Cells | abstract |
Sept 14 | Towfiq Ahmed | Los Alamos National Lab | First-Principles Electronic Structure Methods for Complex Systems: From Strongly Correlated Systems to van der Waals Hetero-structures. | abstract |
Sept 17 | Hamidreza Ramezani | University of California Berkeley | Mastering waves with non-Hermiticity | abstract |
Nov 13 | Qiming Zhang | University of Texas Arlington | Cost-effective solar-cell materials searched by modeling and simulations | abstract |